to Thrip Feeding - Plant and Cell Physiology

Function of Jasmonate in Response and Tolerance of Arabidopsisto Thrip Feeding

Hiroshi Abe1,*, Jun Ohnishi

2, Mari Narusaka

3, Shigemi Seo

4, Yoshihiro Narusaka

3, Shinya Tsuda

2and

Masatomo Kobayashi1

1 Department of Biological Systems, RIKEN BioResource Center, Tsukuba, 305-0074 Japan2 Department of Plant Pathology, National Agricultural Research Center, Tsukuba, 305-8666 Japan3 Research Institute for Biological Sciences, Okayama, 7549-1 Yoshikawa, Kibichuo-cho, Okayama 716-1241, Japan4 Department of Plant Physiology, National Institute of Agrobiological Sciences, Tsukuba, 305-8666 Japan

We analyzed the interaction between Arabidopsis and

western flower thrips (Frankliniella occidentalis), which are one

of the most serious insect pests of cultivated plants. We focused

on the function of the immunity-related plant hormones

jasmonate (JA), ethylene (ET) and salicylic acid (SA) in the

plant’s response to thrip feeding. Expression of the marker

genes for each hormone response was induced by thrip feeding in

wild-type (WT) plants. Further analyses in the hormone-related

mutants coi1-1 (JA insensitive), ein2-1 and ein3-1 (ET

insensitive) and eds16-1 (SA deficient) suggested the impor-

tance of these hormones in the plant response to feeding.

Comparative transcriptome analyses suggested a strong

relationship between thrip feeding and JA treatment, but not

ET or SA treatment. The JA content of WT plants was

significantly increased after thrip feeding. Moreover, coi1-1,

but not ein2-1, showed lower feeding tolerance against thrips

than the WT. Application of JA to WT plants before thrip

feeding enhanced the plants’ feeding tolerance. JA modulates

several defense responses in cooperation with ET, but applica-

tion of the ET precursor 1-aminocyclopropane-carboxylic acid

had a marked negative effect on feeding tolerance. Our results

indicate that JA plays an important role inArabidopsis in terms

of response to, and tolerance against, thrip feeding.

Keywords: Arabidopsis thaliana — Ethylene — Frankliniella

occidentalis — Insect feeding — Jasmonate — Western

flower thrips.

Abbreviations: ACC, 1-aminocyclopropane-carboxylic acid;AOC, allene oxide cyclase; AOS, allene oxide synthase; chiB,�-chitinase; coi1-1, coronatine insensitive 1-1; eds16-1, enhanceddisease susceptibility 16-1; ein2-1, ein3-1, ethylene-insensitive 2-1,3-1; ET, ethylene; JA, jasmonic acid; LOX2, lipoxygenase 2;OPDA, 12-oxo-phytodienoic acid; PDF1.2, plant defensin 1.2; SA,salicylic acid; VSP2, vegetative storage protein 2; WT, wild type.

Introduction

Insect feeding retards plant growth and decreases crop

productivity. Plants develop defense systems against insect

feeding by constitutive and inducible protective responses

(reviewed by Walling 2000, Kessler and Baldwin 2002,

Korth and Thompson 2006), many of which remain

unclear. Recently, plant responses to insect feeding have

been analyzed at the molecular, cellular and physiological

levels (reviewed by Kessler and Baldwin 2002, Korth and

Thompson 2006, Turlings and Ton 2006), although these

analyses of plant–herbivore interaction have focused on

limited types of insect species (mostly lepidopteran larvae

and aphids).

The western flower thrip (Frankliniella occidentalis

[Pergande]) is one of the most important insect herbivores

and is an exotic pest of greenhouse production in many

countries. Thrips use their mouthparts to pierce plant cells

and suck out the contents. This feeding mode differs from

those of the well-studied caterpillars or aphids (reviewed by

Walling 2000, Thompson and Goggin 2006), and thrips can

also act as virus vectors (reviewed by Parrella 1995).

Because the thigmokinetic behavior of western flower

thrips (i.e. their tendency to occupy narrow crevices

within or between plant parts) and the emergence of

insecticidal resistance, it is difficult to control this species

with insecticides (reviewed by Jensen 2000). Therefore,

elucidation of the molecular mechanism of the plant

response to the feeding of western flower thrips is important

for the development of new methods to prevent damage.

The plant hormones jasmonic acid (JA), ethylene (ET)

and salicylic acid (SA) mediate a variety of physiological

processes, including the basal plant defense responses

induced by various biotic stresses such as fungal, bacterial

and viral infections (reviewed by Pieterse et al. 2006). The

hormonal defense responses in plants are classified into two

major pathways: the SA pathway and the JA/ET pathway

(reviewed by Thomma et al. 2001). The SA-mediated

defense response provides resistance to biotrophic fungi

and bacteria such as Peranospora parasitica and

Pseudomonas syringae (Uknes et al. 1992). Activation of

the SA-mediated defense response is related to the

hypersensitive response, which triggers systemic acquired

resistance. In contrast, the JA/ET-mediated pathway

*Corresponding author: E-mail, [email protected]; Fax, þ81-29-836-9053.

Plant Cell Physiol. 49(1): 68–80 (2008)doi:10.1093/pcp/pcm168, available online at www.pcp.oxfordjournals.org� The Author 2007. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.All rights reserved. For permissions, please email: [email protected]

68

Dow

nloaded from https://academ

ic.oup.com/pcp/article/49/1/68/1903854 by guest on 09 D

ecember 2021

appears to regulate resistance against necrotrophic fungi

such as Alternaria brassicicola and Botrytis cinerea

(Thomma et al. 1998).

In addition, there are at least two modes of interaction

between JA and ET, one synergistic and the other

antagonistic (reviewed by Pieterse et al. 2006). Expression

of �-chitinase (chiB) and plant defensin (PDF1.2), marker

genes of the JA/ET pathway, is induced by application of

either JA or ET, and a synergistic effect occurs when both

hormones are applied. However, expression of vegetative

storage protein 2 (VSP2) and lipoxygenase 2 (LOX2),

marker genes of the JA pathway, is induced by JA but

not by ET. The effect of JA on the expression of these genes

is antagonistically reduced by ET treatment (reviewed by

Lorenzo and Solano 2005). Campbell et al. (2002) reported

that expression of some defense-related genes might be

regulated through the coordination of multiple signaling

cascades. Thus, it is important to examine the involvement

of each hormone in each biotic stress response.

The plant hormones JA, ET and SA also appear to

have important functions in plant responses to insect

feeding (reviewed by Walling 2000, Korth and Thompson

2006). In Arabidopsis, Ellis et al. (2002) reported that the

constitutive JA signaling mutant cev1 shows higher

tolerance to aphids, whereas tolerance is decreased in the

JA-insensitive mutant coi1-1. The tomato spr2 mutant, a

mutant that shows loss of function of fatty acid desaturase

and is involved in JA biosynthesis, is compromised in

defense against attack by tobacco hornworm larvae

(Li et al. 2003). In Nicotiana attenuata, JA regulates the

accumulation of the potent defense metabolite nicotine, and

ET suppresses the JA-induced accumulation of nicotine.

Attack of the leaves of N. attenuata by its specialist

herbivore Manduca sexta elicits ET synthesis, and as a

result the nicotine content in N. attenuata is decreased or

unchanged (Kahl et al. 2000, Winz and Baldwin 2001). This

well-understood scheme demonstrates the relationship

between plant–insect interactions and the functions of

plant hormones.

Studies have also clarified the function of SA in plant

tolerance against insect attack. Application of the SA

analog benzothiadiazole to tomato reduces the population

growth of aphids (Cooper et al. 2004). In addition, cpr5 and

ssi2 mutants, which have an elevated SA level and a

constitutively active SA-dependent signal, respectively,

showed increased tolerance to aphid population growth

(Pegadaraju et al. 2005). In contrast, the reduced SA

accumulation mutant pad4 showed decreased tolerance to

aphid population growth (Pegadaraju et al. 2005). The

expression of various genes is induced by the feeding of

insects, such as aphids and caterpillars (Moran and

Thompson 2001, Moran et al. 2002, Hui et al. 2003,

Thompson and Goggin 2006); the expression of many of

these feeding-inducible genes is also induced by JA/ET or

SA treatment (Moran and Thompson 2001). However, the

molecular mechanism underlying the function of these plant

hormones in feeding response remains unclear.

In this study, we analyzed the function of JA, ET

and SA in the response of Arabidopsis to thrip feeding.

Expression analyses of marker genes suggested the involve-

ment of these hormones in the response to thrip feeding. The

expression of marker genes was reduced or canceled in the

hormonal mutants. In addition, we performed comparative

transcriptome analyses in Arabidopsis treated with thrips,

JA, ET or SA. JA contents were increased after thrip feeding,

and the results demonstrated the greater importance of JA

than ET or SA in the Arabidopsis response to thrip feeding.

In addition, the coi1-1 (JA-insensitive) mutant showed

decreased feeding tolerance against thrips; application of

JA enhanced its feeding tolerance against thrips, whereas ET

application had no such effect. We discuss the function of JA

and ET in the feeding tolerance of Arabidopsis.

Results

Expression of marker genes involved in hormone responses

We analyzed the JA-, ET- or SA-inducible expression

of several marker genes in Arabidopsis. Expression of VSP2

and LOX2, marker genes of the JA pathway, was induced

by thrip feedings. This induction was not observed in

control plants (Fig. 1A). Similarly, the expression of chiB

and PDF1.2, marker genes of the JA/ET pathway, and of

the SA-inducible genes PR1 and BGL2 was also induced by

thrip feeding (Fig. 1B, C). Because these results indicated

that JA, ET and SA production was affected by thrip

feeding, we used hormonal mutants (i.e. the JA-insensitive

mutant coi1-1, the ET-insensitive mutants ein2-1 and ein3-1,

and the SA-deficient mutant eds16-1) to analyze the

induction of expression of marker genes by thrip feeding

(Chao et al. 1997, Xie et al. 1998, Alonso et al. 1999,

Dewdney et al. 2000, Wildermuth et al. 2001). Expression of

VSP2 and chiB, marker genes of the JA and JA/ET

pathways, respectively, was induced less in the

JA-insensitive coi1-1 mutant than in the control plant

(Fig. 2A). Expression of chiB was also reduced in the

ET-insensitive ein2-1 and ein3-1 mutants (Fig. 2B), but

induction of expression of the VSP2 gene was not reduced

in these mutants (Fig. 2B). Expression of PR1 and BGL2 in

the SA-deficient mutant eds16-1was markedly reduced

(Fig. 2C). These results suggest the possible involvement

of JA, ET and SA signals in the feeding-inducible gene

expression of Arabidopsis by thrips.

Correlation between thrip feeding and hormone treatments

Microarrays are convenient tools that are used to

investigate the correlation in gene expression between insect

JA but not ET acts in Arabidopsis tolerance to thrips 69

Dow



ecember 2021

5VSP2 geneA

4R

elat

ive

expr

essi

on

3

2

1

0

0h

5h

10h

24h

5h

10h

24h

−Feeding +Feeding

5LOX2 gene

4

Rel

ativ

e ex

pres

sion

3

2

1

0

0h

5h

10h

24h

5h

10h

24h

−Feeding +Feeding

5PDF1.2 geneB

4

Rel

ativ

e ex

pres

sion

3

2

1

0

0h

5h

10h

24h

5h

10h

24h

−Feeding +Feeding

5CHIB gene

4R

elat

ive

expr

essi

on

3

2

1

0

0h

5h

10h

24h

5h

10h

24h

−Feeding +Feeding

5BGL.2 geneC

4

Rel

ativ

e ex

pres

sion

3

2

1

0

0h

5h

10h

24h

5h

10h

24h

−Feeding +Feeding

5PR1 gene

4

Rel

ativ

e ex

pres

sion

3

2

1

0

0h

5h

10h

24h

5h

10h

24h

−Feeding +Feeding

Fig. 1 Expression of marker genes for JA, ET and SA signals is induced by thrip feeding in Arabidopsis. (A) VSP2 and LOX2 as markergenes for the JA pathway, (B) chiB and PDF1.2 as marker genes for the JA/ET pathway and (C) PR1 and BGL2 as marker genes for the SApathway. Five 3-week-old plants were grown in a single pot, and 25 adult female thrips were allowed to feed on plants. After 0, 5, 10 and24 h, total RNA was prepared from the plants with (þFeeding) or without (�Feeding) thrip feeding, and first-strand cDNA was synthesizedfor PCR analysis. Primer sequences used in this analysis are described in Materials and Methods. The expression level of each gene wasnormalized to the expression of CBP20 (control) and is shown as the relative value. Each value represents the average of 10 plants �SD ofthree replications.

70 JA but not ET acts in Arabidopsis tolerance to thrips

Dow



ecember 2021

A5

VSP2 gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

WT

0h

5h

Fee

ding

24h

Fee

ding 0h

5h

Fee

ding

24h

Fee

ding

coi1-1

5CHIB gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

WT

0h

5h

Fee

ding

24h

Fee

ding 0h

5h

Fee

ding

24h

Fee

ding

coi1-1

C5PR1 gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

WT

0h

5h

Fee

ding

24h

Fee

ding 0h

5h

Fee

ding

24h

Fee

ding

eds16-1

5BGL2 gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

WT

0h

5h

Fee

ding

24h

Fee

ding 0h

5h

Fee

ding

24h

Fee

ding

eds16-1

B5

CHIB gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

WT

0h

5h

Fee

ding

5h

Fee

ding

24h

Fee

ding

24h

Fee

ding0hr

0hr

5h

Fee

ding

24h

Fee

ding

ein2-1 ein3-1 WT

0h

5h

Fee

ding

5h

Fee

ding

24h

Fee

ding

24h

Fee

ding0hr

0hr

5h

Fee

ding

24h

Fee

ding

ein2-1 ein3-1

5VSP2 gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

Fig. 2 Expression of marker genes for JA, ET and SA signals induced by thrip feeding is suppressed in coi1-1, ein2-1, ein3-1 and eds16-1mutants. (A) VSP2 and LOX2 in Columbia (WT) and the JA-insensitive mutant coi1-1, (B) chiB and PDF1.2 in WT and the ET-insensitivemutants ein2-1 and ein3-1, and (C) PR1 and BGL2 in WT and the SA-deficient mutant eds16-1. Analyses were the same as described in thelegend to Fig. 1.


Dow



ecember 2021

and hormone treatments. Narusaka et al. (2006) designed

an Arabidopsis microarray consisting of 1.2K full-length

cDNA clones representing the putative defense-related and

regulatory genes. These 1.2K genes were selected from

among the genes covered by the Arabidopsis 7K array

(RIKEN, Japan; Seki et al. 2002) and Arabidopsis oligo

microarray (Agilent Technologies, Santa Clara, CA, USA;

Narusaka et al. 2003a, Narusaka et al. 2003b, Narusaka

et al. 2004). Treatment of Arabidopsis Col-0 WT plants with

SA, JA and ET induced the expression of 282, 159 and 246

genes, respectively (Narusaka et al. 2006). We used the

1.2K cDNA microarray to compare the gene expression

patterns between thrip feeding and JA, ET or SA treatment.

Thrips fed on Arabidopsis plants for 2, 5, 10 or 24 h, and

plants were snap-frozen in liquid nitrogen and stored at –

808C until RNA extraction. The relationship between

experimental pairs was analyzed by means of Pearson’s

correlation coefficient with the software Excel 2004 for Mac

ver. 11.2.3 (Microsoft, Redmond, WA, USA). Several

authors have offered guidelines for the interpretation of

the correlation coefficient. Cohen (1998), for example, has

suggested the following interpretations for correlations:

0� r50.10 is regarded as an insubstantial; 0.10� r50.30 as

a small; 0.30� r50.50 as a medium; and 0.50� r51.00 as a

large correlation. The analyses revealed significant correla-

tions between thrip feeding and JA treatment but not ET or

SA treatment (Table 1A). The correlation coefficient was

large or medium between thrip feeding and JA treatment,

except thrip feeding for 2 h and JA treatment for 10 h. These

results indicate the importance of JA in the response to

thrip feeding. The correlation between thrip feeding and ET

or SA treatment was insubstantial. Most of these pairs,

except thrip feeding for 2 h and ET treatment for 2 h,

showed a correlation50.2 suggesting that they are not close

or show a negative correlation. We also detected the

correlation between JA and ET (Table 1B). The relationship

between JA and ET treatment, based on transcriptome

analyses, was reported previously (Schenk et al. 2000).

Therefore, we further analyzed the function of JA in the

response of Arabidopsis to thrip feeding to investigate

whether ET was also involved in the response.

Jasmonate functions as a regulator of plant response to thrip

feeding

To analyze the function of JA in the response to thrip

feeding, we measured the contents of JA in plants fed on by

thrips. The JA content of plants 24 h after thrip feeding was

11.8 times that before feeding; in plants that had not been

fed on, the JA level after 24 h was 1.4 times that before

feeding, i.e. virtually unchanged (Fig. 3A). Next, we

analyzed the expression of the genes allene oxide synthase

(AOS) and allene oxide cyclase 2 (AOC2), both of which

encode enzymes that catalyze JA biosynthesis (Delker et al.

2006; Fig. 3C), in plants with or without thrip feeding.

Induction of the expression of both genes was apparent 24

and 48 h after thrip feeding (Fig. 3D, E). However,

biosyntheses of ET was not increased in the plants 24 h

after thrip feeding (Fig. 3B). We detected elevated ET levels

in the eto1-1 mutant (an overproducer of ET) under control

conditions, suggesting that our experimental design was

valid (Fig. 3B).

Next, we used the JA-insensitive mutant coi1-1 to

analyze the function of JA in the tolerance of Arabidopsis to

thrip feeding. Arabidopsis rosette leaves were cut into discs

8mm in diameter. One adult female thrip was put on the

leaf disc and allowed to feed. After 1 or 2 d, we determine

the area of the feeding scar on each leaf disc (n¼ 10;

Fig. 4A, B). After 2 d of feeding, the area of feeding scars

was significantly larger than that after 1 d of feeding in both

WT and mutant plants, suggesting the validity of this

Table 1 Correlation coefficients between experimental pairs in the microarray analyses

JA 2 h JA 5h JA 10h JA 24 h ET 2h ET 5h ET 10 h ET 24 h SA 2h SA 5h SA10h SA 24 h

A Thrips 2 h 0.31� 0.44� 0.25� 0.31� 0.22� –0.04 0.02 0.06 0.07 0.02 0.09 0.24�

Thrips 5 h 0.38� 0.56� 0.51� 0.33� 0.01 –0.10 –0.07 0.01 –0.06 –0.06 0.00 0.15�

Thrips 10 h 0.30� 0.55� 0.55� 0.34� –0.07 –0.16� –0.11� –0.04 –0.09 –0.13� –0.09 0.07

Thrips 24 h 0.37� 0.60� 0.65� 0.42� –0.05 –0.11 –0.06 0.03 –0.10 –0.14� –0.09 0.10

B JA 2h – – – – 0.58� 0.30� 0.30� 0.50� 0.12� –0.04 –0.06 0.06

JA 5h – – – – 0.52� 0.41� 0.38� 0.54� 0.07 –0.03 0.06 0.13�

JA 10 h – – – – 0.44� 0.40� 0.44� 0.56� –0.03 –0.05 0.01 0.12�

JA 24 h – – – – 0.61� 0.43� 0.49� 0.76� –0.02 –0.17� –0.13� 0.18�

Total RNA was isolated 2, 5, 10, and 24 h after treatment with 5mM SA, 0.1mM JA or 1mM ET (Narusaka et al. 2006), or thrips feeding.Each experiment was replicated three times with 10–15 plants per sample. To obtain sufficient material, samples from replicateexperiments were pooled before RNA extraction. We conducted two or three independent microarray analyses with the same RNA.Asterisks indicate significant difference at P50.05.A complete data set is available at http://www.ncbi.nlm.nih.gov/geo/ with accession numbers GSM239486, GSM241219, GSM241220,GSM241221 and GSM86106.


Dow



ecember 2021

http://www.ncbi.nlm.nih.gov/geo/

experimental system (Fig. 4I–K). The area of feeding scars

in coi1-1 mutants was significantly greater than that in WT

plants (Fig. 4C, D, I). To analyze the direct effect of JA on

thrip performance, we treated the coi1-1 mutant with 50 mMmethyl jasmonate 24 h before the beginning of feeding and

then determined the area of the feeding scar after 2 d of

thrip feeding. Application of JA to coi1-1 mutants did not

have a significant effect on thrip feeding (Fig. 4J). WT

plants were treated in the same manner; the feeding scar on

the JA-treated plants was significantly smaller than that on

untreated plants (Fig. 4E, F, K).

We next used whole Arabidopsis plants to analyze the

effect of JA treatment on feeding tolerance. JA treatment

enhanced feeding tolerance compared with that in untreated

plants (Fig. 4G, H). The effectiveness of JA application on

thrip feeding was evaluated by the electrolyte leakage test.

Electrolyte leakage was significantly lower in plants treated

with JA than in untreated plants (Fig. 4L). Together with

the results from the leaf disc assay, these results indicate

that JA is able to induce acquired resistance against thrip

feeding.

Ethylene does not enhance tolerance against thrip feeding

JA and ET have a synergistic role in some disease

responses via the JA/ET pathway (reviewed by Lorenzo and

Solano 2005). To understand the role of ET in tolerance

against thrip feeding, we analyzed the feeding rate in ein2-1

mutants. The ein2-1 mutants suffered a level of damage by

thrip feeding similar to that in WT plants (Fig. 5A, B, E).

Next, we analyzed the effect of ET application on thrip

feeding. Application of the ET precursor 1-aminocyclopro-

pane-carboxylic acid (ACC) 24 h before thrip feeding

increased the area of feeding scars compared with that in

untreated plants (Fig. 5C, D, F). These results indicate that

ET does not have any positive effect on Arabidopsis

400A

D

300

JA c

onte

nts

(ng/

gFW

)

200

100

0

5AOS gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

0h

0h 24h−Feeding

24h+Feeding

5B C

4

Rel

ativ

e co

nten

ts

2

3

1

024h

−Feeding

WT

24h−Feeding

24h+Feeding

eto1-1

Linoleic Acid (LA)

12-oxo-phytodieonic acid (OPDA)

LOX

AOS

AOC

OPR3

JA

24h

−Feeding

48h

48h

24h

E5

AOC2 gene

4

3

Rel

ativ

e ex

pres

sion

2

1

0

0h

24h

48h

48h

24h

+Feeding −Feeding +Feeding

Fig. 3 Effect of thrip feeding on the biosynthesis of JA and ET in Arabidopsis. (A, B) Endogenous levels of JA (JAþmethyl JA; A) and ET (B).Ten adult female thrips were allowed to feed on a 3-week-old plant in a closed container with air vents (þFeeding). The control plant waskept in a container without thrips (�Feeding). At the beginning of the experiment (0 h) and after 24 h from the start of feeding, 1 g of planttissue was harvested for the extraction of RNA. The results shown are means� SDs of three independent measurements. (C) Proposedmodel of the pathway of biosynthesis of JA in Arabidopsis. (D, E) Expression levels of the marker genes of JA biosynthesis, AOS (D) andAOC2 (E). Analyses were the same as described in the legend to Fig. 1.


Dow



ecember 2021

WT

coi1-1

5I

4

3

Rel

ativ

e ar

ea o

f fee

ding

sca

rs

2

1

01 day 2 days

Control

JA treatment

5J

4

3

Rel

ativ

e ar

ea o

f fee

ding

sca

rs

2

1

0WT coi1-1

Control

JA treatment

5K

4

3

Rel

ativ

e ar

ea o

f fee

ding

sca

rs

2

1

01 day 2 days

5L

4

3

Rel

ativ

e io

n le

akag

e

2

1

00hr

feeding

+ JA− JA

A B C D

E F G H

Fig. 4 Function of JA in plant tolerance against thrip feeding. (A) A western flower thrip on a leaf disc of Arabidopsis (8mm diameter); thefeeding scar is within the dashed circle. (B) A magnified image of (A). (C, D, I) Three-week-old WT plants and coi1-1 mutants were used,and each leaf disc was fed on by one adult female thrip. Typical image of the leaf discs of WT (C) and coi1-1 (D) after feeding for 2 d.(I) Mean� SD of the area of feeding scars on WT and coi1-1 leaf discs, based on410 independent determinations. (E, F, K) Either 50 mM JA(JA treatment) or water (control) was sprayed on 3-week-old WT Arabidopsis plants 1 d before thrip feeding. Typical leaf discs of control(E) and JA-treated plants (F) after 2 d of thrip feeding. (K) Mean� SD of the feeding scar area in control and JA-treated WT plants, based on10 independent determinations. (G, H, L) Three-week-old WT plants were sprayed with water (�JA; G) or 50 mM JA (þJA; H), and 1 d later25 adult female thrips were allowed to feed on each for 2 d. (L) Mean� SD of relative electrolyte leakage of plants (0 h) and after thefeeding experiment (�JA and þJA), based on five independent determinations. (J) Jasmonate (50 mM, JA treatment) or water (control) wassprayed on 3-week-old WT and coi1-1 plants. One day later one adult female thrip was allowed to feed on a leaf disc from each plant.Values are means� SDs of410 independent determinations.


Dow



ecember 2021

tolerance against thrip feeding. Thus, the JA pathway alone

is involved in tolerance against thrip feeding.

Discussion

The phytohormones JA, ET and SA regulate the plant’s

basal immune system. Numerous studies have examined the

functions of these hormones in plant response to pathogen

attack (reviewed by Pieterse et al. 2006). Here, we analyzed

the induction of gene expression by thrip feeding in

Arabidopsis to understand the plant’s hormonal response

to feeding. Gene expression patterns regulated by these

hormones are categorized into at least two signal pathways:

the JA/ET pathway and the SA pathway. Negative interac-

tion between the JA/ET and SA pathways has been clearly

shown by previous studies (e.g. Niki et al. 1998), and these

pathways have different effects on plant resistance to

pathogens (Uknes et al. 1992, Thomma et al. 1998).

Expression of the genes VSP2 and LOX2 (markers for

the JA pathway), PDF1.2 and chiB (markers for the JA/ET

pathway), and PR1 and BGL2 (markers for the SA

pathway) was induced by thrip feeding (Fig. 1). Schenk

et al. (2000) reported that up-regulation of some of the

Arabidopsis genes expressed under infection by A. brassici-

cola was also induced by treatments with JA, ET or SA,

suggesting interaction and coordination between the hor-

monal pathways in the plant defense response. From this

point of view, we analyzed the expression levels of marker

genes in the JA-insensitive mutant coi1-1, the ET-insensitive

mutants ein2-1 and ein3-1, and the SA-deficient mutant

eds16-1 fed on by thrips. Induction of VSP2 by thrip

feeding was apparently reduced in coi1-1 but not in ein2-1

and ein3-1. In contrast, induction of chiB was reduced in

coi1-1, and in ein2-1 and ein3-1 (Fig. 2A, B). Induction of

PR1 and BGL2 was reduced in eds16-1 (Fig. 2C). These

results suggest the possible importance of JA, ET and SA

signals in the response of Arabidopsis to thrip feeding.

Further comparative transcriptome analyses to show

the importance of these plant hormones indicated the greater

importance of JA than ET and SA in the plant’s response to

thrip feeding (Table 1A). As reported by Schenk et al. (2000),

we also found a significant relationship of gene expression

profiles between JA and ET treatments (Table 1B).

Therefore, we next determined the JA and ET contents of

plants with or without thrip feeding. JA contents were

apparently increased 24 h after thrip feeding (Fig. 3A),

whereas ET contents were not elevated (Fig. 3B). Expression

of AOS and AOC2, which regulate JA biosynthesis, was also

induced by thrip feeding (Fig. 3D, E). These results suggest

that JA biosynthesis after thrip feeding may be important for

A B C D

WT5E

4

3

2

Rel

ativ

e ar

ea o

f fee

ding

sca

rs

1

01 day 2 days

ein2-1

Control5F

4

3

2

Rel

ativ

e ar

ea o

f fee

ding

sca

rs

1

01 day 2 days

ACC treatment

Fig. 5 Ethylene does not have a positive effect on feeding tolerance against thrips. (A, B, E) One adult female thrip was allowed to feed ona leaf disc of 3-week-old WT plants and ein2-1 mutants. Typical image of leaf discs from WT (A) and ein2-1 (B) 2 d after the start of thripfeeding. (E) Mean� SD of the area of feeding scars, based on410 independent determinations. (C, D, F) The ET precursor ACC (25 mMdissolved in 25mM MES buffer, pH. 5.7; ACC treatment) or MES buffer (control) was sprayed on 3-week-old WT Arabidopsis plants 1 dbefore thrip feeding. One adult female thrip was allowed to feed on a leaf disc from each plant. Typical images of leaf discs from a control(C) and ACC-treated plant (D) 2 d after the start of thrip feeding are shown. (F) Mean� SDs of the area of feeding scars, based on410independent determinations.


Dow



ecember 2021

plant tolerance against thrips. The self-organizing maps

(SOMs) analyses to cluster the gene expression pattern found

how the correlation between thrip feeding and JA treatment

is different from the correlation between JA and ET treat-

ment in comparative transcriptome analyses. The correlation

between thrip feeding and JA treatment is based on the genes

which are induced by both thrip feeding and JA treatment,

but not by ET treatment. On the other hand, the correlation

between JA and ET treatment is based on the genes which are

induced by thrip feeding and repressed by JA and ET

treatment (data not shown).

JA and ET regulate the expression of PDF1.2 and chiB.

Expression of these genes was induced by thrip feeding, but

the induction was suppressed in the coi1-1, ein2-1 and ein3-1

mutants (Fig. 2A, B). Likewise, Penninckx et al. (1998)

reported that expression of PDF1.2 was not induced by JA

in ein2-1 nor by ET in coi1-1. Studies have demonstrated

that ERF1, a positive regulator of PDF1.2 and chiB gene

expression, acts as a key factor in the integration of both JA

and ET signals (reviewed by Lorenzo and Solano 2005). JA

and ET also induce the expression of ERF1. Consistent with

the expression of PDF1.2, the expression of ERF1 has not

been induced by JA in ein2-1, nor by ET in coi1-1. On the

basis of these findings, it has been suggested that the

simultaneous requirement for JA and ET signals for ERF1

expression explains the interaction of JA and ET signals

(Lorenzo and Solano 2005). Judging from these reports and

the absence of ET production after thrip feeding, expression

of PDF1.2 and chiB appears to be regulated by JA rather

than by the JA/ET pathway.

Although the SA-inducible genes PR1 and BGL2 were

induced by thrip feeding (Fig. 1B, C), correlation analyses

using transcriptome data did not indicate the importance of

SA in plant response to thrip feeding (Table 1A). Thus, the

biological significance of PR1 and BGL2 induction by thrip

feeding is unclear. Further investigations are needed to

clarify how Arabidopsis plants respond to thrip feeding

through the antagonistic plant hormones JA and SA.

Acquired resistance is one effective strategy for

protection against biotic or abiotic stresses (reviewed by

Thomashow 1999, Burke et al. 2000, Grant and Lamb

2006). We analyzed feeding tolerance in plants with or

without JA application to understand the function of JA in

acquired resistance against thrip feeding. Treatment of

Arabidopsis with JA enhanced tolerance to thrip feeding in

both leaf disc and whole-plant assays (Fig. 4J, K),

indicating that JA may induce acquired resistance against

thrip feeding in Arabidopsis. We also analyzed the feeding

tolerance in a JA-insensitive coi1-1 mutant. In contrast to

the results of the JA application assay, thrips fed on this

mutant more than on the WT plants (Fig. 4I).

Recent studies on plant–herbivore interactions indi-

cated the role of plant volatiles as olfactory signals for

insect behavior (Kessler and Baldwin 2001, Li et al. 2002,

Aharoni et al. 2003, Bruce et al. 2005). In this study we used

methyl jasmonate, a major plant volatile substance. To

eliminate the possibility that methyl jasmonate directly

changed the thrips’ behavior, we treated the coi1-1 mutant

with methyl jasmonate and found that this volatile had no

effect on thrip feeding on coi1-1 (Fig. 4L). Therefore, we

concluded that JA enhances resistance against thrip feeding

via JA-regulated defense responses.

Glucosinolates are secondary metabolites, the volatile

breakdown products of which have biological activity

against herbivores and pathogens (Bones et al. 1996,

Raybould and Moyes 2001, Barth and Jender 2006).

Sasaki-Sekimoto et al. (2005) reported that the biosynthesis

of glucosinolate is regulated by JA. Thus, glucosinolate may

be one of the metabolites that plays a role in JA-inducible

acquired resistance against thrip feeding.

In Arabidopsis, cev1, a constitutively active mutant for

JA signaling, showed higher tolerance to aphids than the

WT, whereas the JA-insensitive mutant coi1-1 showed

decreased tolerance against these insect pests (Ellis et al.

2002). Analyses of the interaction between the coi1-1

mutant and cabbage white butterfly larvae support the

importance of JA in insect feeding (Reymond et al. 2004).

Recently, the JAZ (jasmonate ZIM-domain) family of

repressors was identified as the negative regulator of JA

signaling (Chini et al. 2007, Thines et al. 2007, Yan et al.

2007). The JAZ repressor interacts with COI1 protein,

which leads the degradation of JAZ protein to induce

JA-responsive gene expression. Interestingly, JA-Ile but not

JA stimulates the interaction between JAZ repressor and

COI1. JA-Ile may be involved in the enhancement of

tolerance to thrip feeding promoted by JA application.

There is a long-term debate on a separate wounding

signal regulated by JA and the cyclopentenone precursor of

JA, 12-oxo-phytodienoic acid (OPDA). Taki et al. (2005)

identified a set of genes that specifically responded to

OPDA but not to JA, and they indicated a difference

between JA signaling and OPDA signaling. Interestingly, a

set of genes induced by thrip feeding includes these OPDA-

specific response genes (data not shown). Further analyses

using the opr3 mutant, which lack a major metabolizing

enzyme from OPDA to JA, would indicate the functional

importance and difference of JA and OPDA in plant

response and tolerance to thrip feeding.

Insect pests feed on plants through various modes.Most

studies have investigated lepidopteran larvae, which chew

plant tissues, and aphids, which suck phloem from plants.

Thrips, however, use their mouthparts to pierce plant cells

and suck out their contents (reviewed by Parrella 1995). Our

correlation analyses indicated the importance of JA in plant

response to thrip feeding, and similar results have

been reported in response to aphids and caterpillars.


Dow



ecember 2021

Reymond et al. (2004) reported that many genes induced by

Pieris rapae and Spodoptera littoralis feeding are controlled

by JA. To clarify the details of the various plant–herbivore

interactions, more research on the molecular differences in

plant responses to the different modes of insect feeding is

needed.

JA is involved in the wounding response of plants. In the

wounding pathway (JA pathway), ET has an antagonistic

effect (O’Donnell et al. 1996). However, JA acts in

cooperation with ET during the plant defense response to

fungal attack (JA/ET pathway). We analyzed the effect of

ET application on thrip feeding to understand the role of ET

in plant tolerance to thrip attack. When the ET precursor

ACC was applied to Arabidopsis, the area of thrip feeding

scars was greater than in the controls (Fig. 5F). In addition,

the ET-insensitive mutant ein2-1 was damaged by thrips to

an equal or lesser degree than were WT plants (Fig. 5E).

These results suggest that JA functions separately from ET

during the response to thrip feeding. Thus, the wounding

response may be involved in tolerance against the piercing

and sucking feeding mode of thrips.

Different gene expression in response to mechanical

wounding and insect feeding is reported (Reymond et al.

2000). It is known that gene expression is controlled by

insect oral factors as well as insect feeding (reviewed by

Korth 2003). In addition, Little et al. (2007) reported that

oviposition by Pieris brassicae triggers defense responses,

which are mostly independent of JA signaling. We should

analyze and understand the plant response challenged by

the complexity of insect attack including feeding, oral

factors and oviposition.

Our results demonstrated the importance of JA in the

plant response to, and tolerance against, thrip feeding. ET

did not have such an effect on thrip feeding, although its

action in the plant defense system is connected with that of

JA. In addition to feeding on plants, western flower thrips

also act as vectors of tospovirus (reviewed by Whitfield

et al. 2005). Thus, western flower thrips damage crops

through both feeding and associated disease. From this

point of view, apart from the JA pathway, there may be

other important pathway(s) that regulate the plant defense

response to feeding against viruliferous thrips. Further

research, including transcriptome and metabolome ana-

lyses, is required to better our understanding of plant–

herbivore interactions. Our results showed that the

Arabidopsis–thrips system is a good tool for clarifying the

detailed mechanisms of the plant defense response to this

important agricultural pest.

Materials and Methods

Plant materials and cultivation

Plants (A. thaliana ecotype Col-0) were grown in soil asdescribed previously (Weigel and Glazebrook 2002). Several

mutants related to plant hormone biosynthesis and signaling(coi1-1, ein2-1, ein3-1, eto1-1 and eds16–1) were used in this study.Arabidopsis seeds were sown on sterile soil in pots, moistened, andplaced in a cold room at 48C in the dark to synchronizegermination. The pots were then transferred to 228C with a long-day photoperiod (16 h light/8 h dark). Plants at the four-leafstage were transferred individually to pots and grown to therosette stage.

Identification of coi1-1 plants

Homozygous coi1-1 plants were selected by PCR analysisfollowed by BsmI digestion. Genomic DNA was extracted from asingle rosette leaf of each plant and purified with a DNeasy PlantKit (Qiagen, Valencia, CA, USA), and the PCR was performedwith ExTaq DNA polymerase (TAKARA, Kyoto, Japan).Nucleotide sequences of primers were as follows: forward primer,50-GGAAACAGGAGCCCGAGATC-30; reverse primer, 50-TGGATGTTTCTCGGAGCAGC-30. Amplified DNA was treated withBsmI, which digests DNA from the coi1-1mutant only. The reactionmixture was analyzed by agarose gel electrophoresis.

Thrip feeding

Laboratory colonies of F. occidentalis were maintained in aclosed environmental chamber, as described previously (Murai andLoomans 2001). For the assay, female adults 14–21 d afteremergence from the pupal stage were used. They were starved for2–3 h before feeding on test plants. Twenty-five adult females weregrouped and allowed to feed on each whole plant in an acrylcylinder chamber with air ventilation windows covered with a finemesh. This system confined the feeding adults to the chamber andprevented their escape.

Leaf disc assay

Leaf discs with an 8mm diameter were produced with abiopsy punch (Kay Industries, Oyana, Japan). Leaf discs werefloated on 1.5ml of distilled water in wells of a white 1.5ml sampletube stand (Assist, Tokyo, Japan). A single adult female that hadbeen starved for 2–3 h was placed on a single leaf disc. The hole ofthe sample tube was covered with ABI Prism Optical AdhesiveCover (Applied Biosystems, Foster City, CA, USA), and a few tinyholes for air vents during feeding were made by piercing theadhesive cover with a 27G fine injection needle. Thrips wereallowed to feed for 1 or 2 d at 228C. The area of thrip feeding scarson the surface of each leaf disc was measured by ImageJ software(Abramoff et al. 2004) on digitized images taken under a VHX-200digital microscope (Keyence, Osaka, Japan). The measured area ofleaf discs from each treatment was analyzed using JMP software,ver. 5.1 (SAS Institute, Inc., Cary, NC, USA).

Electrolyte leakage assay

Three-week-old Arabidopsis plants grown in soil were fed onby 25 adult female thrips for 1 or 2 d. An electrolyte leakage assaywas performed as described by Weigel et al. (2001).

Arabidopsis 1.2K cDNA microarray analysis

Total RNA was isolated with Trizol reagent (Invitrogen,Carlsbad, CA, USA). mRNA was prepared with an MACSmRNA Isolation Kit (Miltenyi Biotec, Bergisch Glabach,Germany). To ensure the reproducibility of the microarray results,we replicated the experiment twice with 10 Arabidopsis plants persample. To obtain sufficient material for the experiments, wepooled samples from duplicate experiments before RNA


Dow



ecember 2021

extraction. Preparation of fluorescent probes, microarray hybridi-zation, scanning and data analysis were as described previously(Seki et al. 2001). Image analyses and signal quantification wereperformed with ScanArray Express ver. 3.0 (PerkinElmer,Waltham, MA, USA). A lambda control template DNA fragment(TAKARA) was used as an external control to equalize thehybridization signals generated from different samples (Narusakaet al. 2006). The median of 82 signal values obtained from thelambda control template DNA fragment on the 1.2K microarraywas used as an external control. Each experiment was repeatedthree times.

Quantitative reverse–transcription PCR

Five 3-week-old Arabidopsis plants at the rosette stage grownin the same pot were fed on for 5, 10 or 24 h by 25 female adultthrips in the closed container with air vents. Experiments wererepeated twice. After feeding, the plants were frozen in liquidnitrogen for further analyses. Total RNA (2mg) isolated by usingTrizol reagent (Invitrogen) was treated with RNase-free DNase(TAKARA) to eliminate genomic DNA contamination. First-strand cDNA was synthesized with random oligo-hexamers withSuperscript III reverse transcriptase according to the manufac-turer’s instructions (Invitrogen). Quantitative real-time PCR wascarried out with SYBR Green PCR Master Mix (AppliedBiosystems) using the first-strand cDNA as a template on asequence detector system (ABI Prism 7900HT, AppliedBiosystems). Expression of CBP20 was used for normalization asa standard control gene. Nucleotide sequences of the gene-specificprimers were as follows: VSP2 (At5g24770; forward primer,50-GTTAGGGACCGGAGCATCAA-3; reverse primer, 50-AACGGTCACTGAGTATGATGGGT-30); LOX2 (At3g45140; forwardprimer, 50-TTGCTCGCCAGACACTTGC-30; reverse primer,50-GGGATCACCATAAACGGCC-30); chiB (At3g12500; forwardprimer, 50-ACGGAAGAGGACCAATGCAA-30; reverse primer,50-GTTGGCAACAAGGTCAGGGT-30);PDF1.2 (At5g44420; for-ward primer, 50-CCATCATCACCCTTATCTTCGC-30; reverseprimer, 50-TGTCCCACTTGGCTTCTCG-30); BGL2 (At3g57260;forward primer, 50-GCCGACAAGTGGGTTCAAGA-30; reverseprimer, 50-AACCCCCCAACTGAGGGTT-30); PR1 (At2g14610;forward primer, 50-GTTGCAGCCTATGCTCGGAG-30; reverseprimer, 50-CCGCTACCCCAGGCTAAGTT-30); CBP20 (At5g44200; forward primer, 50-CCTTGTGGCTTTTGTTTCGTC-30;reverse primer, 50-ACACGAATAGGCCGGTCATC-30); AOS(At5g42650; forward primer, 50-TCTTCTCTTCGCCACGTGC-30;reverse primer, 50-GGTTATGAACTTGATGACCCGC-3); AOC2(At3g25780; forward primer, 50-CGGCAAGAAACCAACAGAGC-30; reverse primer, 50-GACCTGCCGTGATTCCCAC-30).

Jasmonate quantification

Quantification of JA and its methyl ester was performed asdescribed previously (Seo et al. 1995), except that an HP6890 gaschromatograph fitted to a quadrupole mass spectrometer (Hewlett-Packard, Wilmington, DE, USA) was used for the analysis.Approximately 1 g of each Arabidopsis plant with or without thripfeeding was used for quantification. Analyses were performed onthree independent samples.

Ethylene quantification

ET was quantified with a gas chromatograph (GC-8A;Shimadzu, Kyoto, Japan) as described previously (Ohtsuboet al. 1999).

Accession numbers

The Arabidopsis Genome Initiative gene codes (AGI codes)and GenBank accession Nos., respectively, for the genes mentionedin this article are as follows: VSP2 (At5g24770, AB006778), LOX2(At3g45140, AYO62611), chiB (At3g12500, AY054628), PDF1.2(At5g44420, AY063779), BGL2 (At3g57260, AY099668), PR1(At2g14610, AY064023), CBP20 (At5g44200, AF140219), AOS(At5g42650, AY062828) and AOC2 (At3g25780, AJ308484).

Funding

Ministry of Education, Culture, Sports, Science and

Technology Grant-in-Aid for Scientific Research in area

‘Young Scientist (B)’ to H.A.; 2004 Industrial Technology

Research Grant Program of the New Energy and Industrial

Technology Development Organization of Japan to Y.N.

and H.A.

Acknowledgments

We thank I. Sasaki, S. Kawamura and F. Mori of RIKENBRC, and A. Kawashima, S. Nagai and Y. Matsumura of theNational Agricultural Research Center for their excellent technicalassistance. We also thank Dr. M. Watanabe of NIAS for his kindsupport and helpful discussions, and Dr. K. Yamaguchi-Shinozakiof JIRCAS and Dr. T. Shimoda of NARC for their helpfuldiscussions.

References

Abramoff, M.D., Magelhaes, P.J. and Ram, S.J. (2004) Image processingwith ImageJ. Biophotonics Int. 11: 36–42.

Aharoni, A., Giri, A.P., Deuerlein, S., Griepink, F., de Kogel, W.J.,Verstappen, F.W., Verhoeven, H.A., Jongsma, M.A., Schwab, W. andBouwmeester, H.J. (2003) Terpenoid metabolism in wild-type andtransgenic Arabidopsis plants. Plant Cell 15: 2866–2884.

Alonso, J.M., Hirayama, T., Roman, G., Nourizadeh, S. and Ecker, J.R.(1999) EIN2, a bifunctional transducer of ethylene and stress responses inArabidopsis. Science 284: 2148–2152.

Barth, C. and Jander, G. (2006) Arabidopsis myrosinases TGG1 and TGG2have redundant function in glucosinolate breakdown and insect defense.Plant J. 46: 549–562.

Bones, A.M., Tas, E. and Rossiter, J.T. (1996) The myrosinase–glucosinolate system, its organisation and biochemistry. Physiol. Plant97: 194–208.

Bruce, T.J., Wadhams, L.J. and Woodcock, C.M. (2005) Insect hostlocation: a volatile situation. Trends Plant Sci. 10: 269–274.

Burke, J.J., O’Mahony, P.J. and Oliver, M.J. (2000) Isolation of Arabidopsismutants lacking components of acquired thermotolerance. Plant Physiol.123: 575–588.

Campbell, M.A., Fitzgerald, H.A. and Ronald, P.C. (2002) Engineeringpathogen resistance in crop plants. Transgenic Res. 11: 599–613.

Chao, Q., Rothenberg, M., Solano, R., Roman, G., Terzaghi, W. andEcker, J.R. (1997) Activation of the ethylene gas response pathway inArabidopsis by the nuclear protein ETHYLENE-INSENSITIVE3 andrelated proteins. Cell 89: 1133–1144.

Chini, A., Fonseca, S., Fernandez, G., Adie, B., Chico, J.M., et al. (2007)The JAZ family of repressors is the missing link in jasmonate signaling.Nature 448: 666–671.

Cohen, J. (1998) Differences between correlation coefficients. In StatisticalPower Analysis for the Behavioral Sciences, 2nd edn. Edited by Cohen, J.pp. 109–143. Lawrence Erlbaum Associates, Florence.


Dow



ecember 2021

Cooper, W.C., Jia, L. and Goggin, F.L. (2004) Acquired and R-gene-mediated resistance against the potato aphid in tomato. J. Chem. Ecol.30: 2527–2542.

Delker, C., Stenzel, I., Hause, B., Miersch, O., Feussner, I. andWasternack, C. (2006) Jasmonate biosynthesis in Arabidopsis thaliana:enzymes, products, regulation. Plant Biol. (Stuttg.) 8: 297–306.

Dewdney, J., Reuber, T.L., Wildermuth, M.C., Devoto, A., Cui, J.,Stutius, L.M., Drummond, E.P. and Ausubel, F.M. (2000) Three uniquemutants of Arabidopsis identify eds loci required for limiting growth of abiotrophic fungal pathogen. Plant J. 24: 205–218.

Ellis, C., Karafyllidis, I. and Turner, J.G. (2002) Constitutive activation ofjasmonate signaling in an Arabidopsis mutant correlates with enhancedresistance to Erysiphe cichoracearum, Pseudomonas syringae, and Myzus

persicae. Mol. Plant-Microbe Interact. 15: 1025–1030.Grant, M. and Lamb, C. (2006) Systemic immunity. Curr. Opin. Plant Biol.

9: 414–420.Hui, D., Iqbal, J., Lehmann, K., Gase, K., Saluz, H.P. and Baldwin, I.T.

(2003) Molecular interactions between the specialist herbivore Manduca

sexta (Lepidoptera, Sphingidae) and its natural host Nicotiana attenuata.

V. Microarray analysis and further characterization of large-scalechanges in herbivore-induced mRNAs. Plant Physiol. 131: 1877–1893.

Jensen, S.E. (2000) Insecticide resistance in the western flower thrips,Frankliniella occidentalis. Integr. Pest. Manag. Rev. 5: 131–146.

Kahl, J., Siemens, D.H., Aerts, R.J., Gabler, R., Kuhnemann, F.,Preston, C.A. and Baldwin, I.T. (2000) Herbivore-induced ethylenesuppresses a direct defense but not a putative indirect defense against anadapted herbivore. Planta 210: 336–342.

Kessler, A. and Baldwin, I.T. (2001) Defensive function of herbivore-induced plant volatile emissions in nature. Science 291: 2141–2144.

Kessler, A. and Baldwin, I.T. (2002) Plant responses to insect herbivory: theemerging molecular analysis. Annu. Rev. Plant Biol. 53: 299–328.

Korth, K.L. (2003) Profiling the response of plants to herbivorous insects.Genome Biol. 4: 221.1–221.4.

Korth, K.L. and Thompson, G.A. (2006) Chemical signals in plants:jasmonates and the role of insect-derived elicitors responses toherbivores. In Multigenic and Induced Systemic Resistance in Plants.Edited by Tuzun, S. and Bent, E. pp. 259–278. Springer, New York.

Li, C., Liu, G., Xu, C., Lee, G.I., Bauer, P., Ling, H.Q., Ganal, M.W. andHowe, G.A. (2003) The tomato suppressor of prosystemin-mediated

responses2 gene encodes a fatty acid desaturase required for thebiosynthesis of jasmonic acid and the production of a systemic woundsignal for defense gene expression. Plant Cell 15: 1646–1661.

Li, X., Schuler, M.A. and Berenbaum, M.R. (2002) Jasmonate andsalicylate induce expression of herbivore cytochrome P450 genes.Nature 419: 712–715.

Little, D., Gouthier-Darimont, C., Bressow, F. and Reymond, P. (2007)Oviposition py pierid butterflies triggers defense responses inArabidopsis. Plant Physiol. 143: 784–800.

Lorenzo, O. and Solano, R. (2005) Molecular players regulating thejasmonate signalling network. Curr. Opin. Plant Biol. 8: 532–540.

Moran, P.J. and Thompson, G.A. (2001) Molecular responses to aphidfeeding in Arabidopsis in relation to plant defense pathways. Plant

Physiol. 125: 1074–1085.Moran, P.J., Cheng, Y., Cassell, J.L. and Thompson, G.A. (2002) Gene

expression profiling of Arabidopsis thaliana in compatible plant–aphidinteractions. Arch. Insect Biochem. Physiol. 51: 182–203.

Murai, T. and Loomans, A.J.M. (2001) Evaluation of an improved methodfor mass-rearing of thrips and a thrips parasitoid. Ent. Exp. Appl. 101:281–289.

Narusaka, M., Abe, H., Kobayashi, M., Kubo, Y., Kawai, K., Izawa, N.and Narusaka, Y. (2006) A model system to screen for candidate plantactivators using immmune-induction system in Arabidopsis. Plant

Biotech. 23: 321–327.Narusaka, Y., Narusaka, M., Park, P., Kubo, Y., Hirayama, T., et al.

(2004) RCH1, a locus in Arabidopsis that confers resistance to thehemibiotrophic fungal pathogen Colletotrichum higginsianum. Mol.Plant-Microbe Interact. 17: 749–762.

Narusaka, Y., Narusaka, M., Seki, M., Fujita, M., Ishida, J., et al. (2003a)Expression profiles of Arabidopsis phospholipase A IIA gene in responseto biotic and abiotic stresses. Plant Cell Physiol. 44: 1246–1252.

Narusaka, Y., Narusaka, M., Seki, M., Ishida, J., Nakashima, M., et al.(2003b) The cDNA microarray analysis using an Arabidopsis pad3mutant reveals the expression profiles and classification of genes inducedby Alternaria brassicicola attack. Plant Cell Physiol. 44: 377–387.

Niki, T., Mitsuhara, I., Seo, S., Ohtsubo, N. and Ohashi, Y. (1998)Antagonistic effect of salicylic acid and jasmonic acid on the expressionof pathogesesis-related (PR) protein genes in wounded mature tobaccoleaves. Plant Cell Physiol. 39: 500–507.

O’Donnell, P.J., Calvert, C., Atzorn, R., Wasternack, C., Leyser, H.M.O.and Bowles, D.J. (1996) Ethylene as a signal mediating the woundingresponse of tomato plants. Science 274: 1914–1917.

Ohtsubo, N., Mitsuhara, I., Koga, M., Seo, S. and Ohashi, Y. (1999)Ethylene promotes the necrotic lesion formation and basic PR geneexpression in TMV-infected tobacco. Plant Cell Physiol. 40: 808–817.

Parrella, M.P. (1995) IPM: approaches and prospects. In Thrips Biologyand Management. Edited by Parker, B.L., Skinner, M. and Lewis, T.pp. 357–364. Plenum, New York.

Pegadaraju, V., Knepper, C., Reese, J. and Shah, J. (2005) Premature leafsenescence modulated by the Arabidopsis PHYTOALEXINDEFICIENT4 gene is associated with defense against the phloem-feedinggreen peach aphid. Plant Physiol. 139: 1927–1934.

Penninckx, I.A., Thomma, B.P., Buchala, A., Metraux, J.P. andBroekaert, W.F. (1998) Concomitant activation of jasmonate andethylene response pathways is required for induction of a plant defensingene in Arabidopsis. Plant Cell 10: 2103–2113.

Pieterse, C.M.J., Schaller, A., Mauch-Mani, B. and Conrath, U. (2006)Signaling in plant resistance responses: divergence and cross-talk ofdefense pathways. In Multigenic and Induced Systemic Resistance inPlants. Edited by Tuzun, S. and Bent, E. pp. 166–196. Springer,New York.

Raybould, A.F. and Moyes, C.L. (2001) The ecological genetics of aliphaticglucosinolates. Heredity 87: 383–391.

Reymond, P., Bodenhausen, N., Van Poecke, R.M., Krishnamurthy, V.,Dicke, M. and Farmer, E.E. (2004) A conserved transcript pattern inresponse to a specialist and a generalist herbivore. Plant Cell 16:3132–3147.

Reymond, P., Weber, H., Damond, M. and Farmer, E.E. (2000)Differential gene expression in response to mechanical wounding andinsect feeding in Arabidopsis. Plant Cell 12: 707–719.

Sasaki-Sekimoto, Y., Taki, N., Obayashi, T., Aono, M., Matsumoto, F.,et al. (2005) Coordinated activation of metabolic pathways forantioxidants and defence compounds by jasmonates and their roles instress tolerance in Arabidopsis. Plant J. 44: 653–668.

Schenk, P.M., Kazan, K., Wilson, I., Anderson, J.P., Richmond, T.,Somerville, S.C. and Manners, J.M. (2000) Coordinated plant defenseresponses in Arabidopsis revealed by microarray analysis. Proc. NatlAcad. Sci. USA 97: 11655–11660.

Seki, M., Narusaka, M., Abe, H., Kasuga, M., Yamaguchi-Shinozaki, K.,Carninci, P., Hayashizaki, Y. and Shinozaki, K. (2001) Monitoring theexpression pattern of 1300 Arabidopsis genes under drought and coldstresses by using a full-length cDNA microarray. Plant Cell 13: 61–72.

Seki, M., Narusaka, M., Ishida, J., Nanjo, T., Fujita, M., et al. (2002)Monitoring the expression profiles of 7000 Arabidopsis genes underdrought, cold and high-salinity stresses using a full-length cDNAmicroarray. Plant J. 31: 279–292.

Seo, S., Okamoto, M., Seto, H., Ishizuka, K., Sano, H. and Ohashi, Y.(1995) Tobacco MAP kinase: a possible mediator in wound signaltransduction pathways. Science 270: 1988–1992.

Taki, N., Sekimoto, Y., Obayashi, T., Kikuta, A., Ainai, T., Kobayashi, Y.,Sakurai, N., Suzuki, H., Takamiya, K., Shibata, D. and Ohta, H. (2005)12-oxo-phytodienoic acid triggers expression of a distinct set of genesfrom jasmonates, and plays a role other than intermediate of jasmonatesbiosynthesis. Plant Physiol. 139: 1268–1283.

Thines, B., Katsir, L., Melotto, M., Niu, Y., Mandaokar, A., Liu, G.,Nomura, K., He, S.H., Howe, G.A. and Browse, J. (2007) JAZ repressorproteins are targets of the SCFCOI1 complex during jasmonate signaling.Nature 448: 661–665.

Thomashow, M.F. (1999) PLANT COLD ACCLIMATION: freezingtolerance genes and regulatory mechanisms. Annu. Rev. Plant Physiol.

Plant Mol. Biol. 50: 571–599.


Dow



ecember 2021

Thomma, B., Eggermont, K., Penninckx, I., Mauch-Mani, B.,Vogelsang, R., Cammue, B.P.A. and Broekaert, W.F. (1998) Separatejasmonate-dependent and salicylate-dependent defense-response path-ways in Arabidopsis are essential for resistance to distinct microbialpathogens. Proc. Natl Acad. Sci. USA 95: 15107–15111.

Thomma, B.P., Penninckx, I.A., Broekaert, W.F. and Cammue, B.P. (2001)The complexity of disease signaling in Arabidopsis. Curr. Opin. Immunol.13: 63–68.

Thompson, G.A. and Goggin, F.L. (2006) Transcriptomics and functionalgenomics of plant defence induction by phloem-feeding insects. J. Exp.Bot. 57: 755–766.

Turlings, T.C. and Ton, J. (2006) Exploiting scents of distress: the prospectof manipulating herbivore-induced plant odours to enhance the controlof agricultural pests. Curr. Opin. Plant Biol. 9: 421–427.

Uknes, S., Mauch-Mani, B., Moyer, M., Potter, S., Williams, S.,Dincher, S., Chandler, D., Slusarenko, A., Ward, E. and Ryals, J.(1992) Acquired resistance in Arabidopsis. Plant Cell 4: 645–656.

Walling, L.L. (2000) The myriad plant responses to herbivores. J. PlantGrowth Regul. 19: 195–216.

Weigel, D. and Glazebrook, J. (2002) How to grow Arabidopsis.In Arabidopsis: A Laboratory Manual. Edited by Weigel, D. andGlazebrook, J. pp. 1–18. Cold Spring Harbor Laboratory Press, ColdSpring Harbor, NY.

Weigel, R.R., Bauscher, C., Pfitzner, A.J. and Pfitzner, U.M. (2001)

NIMIN-1, NIMIN-2 and NIMIN-3, members of a novel family of

proteins from Arabidopsis that interact with NPR1/NIM1, a key

regulator of systemic acquired resistance in plants. Plant Mol. Biol. 46:

143–160.Whitfield, A.E., Ullman, D.E. and German, T.L. (2005) Tospovirus–thrips

interactions. Annu. Rev. Phytopathol. 43: 459–489.Wildermuth, M.C., Dewdney, J., Wu, G. and Ausubel, F.M. (2001)

Isochorismate synthase is required to synthesize salicylic acid for plant

defence. Nature 414: 562–565.Winz, R.A. and Baldwin, I.T. (2001) Molecular interactions between the

specialist herbivore Manduca sexta (Lepidoptera, Sphingidae) and its

natural host Nicotiana attenuata. IV. Insect-induced ethylene reduces

jasmonate-induced nicotine accumulation by regulating putrescine

N-methyltransferase transcripts. Plant Physiol. 125: 2189–2202.Xie, D.X., Feys, B.F., James, S., Nieto-Rostro, M. and Turner, J.G. (1998)

COI1: an Arabidopsis gene required for jasmonate-regulated defense and

fertility. Science 280: 1091–1094.Yan, Y., Stolz, S., Chetelat, A., Reymond, P., Pagni, M., Dubugnon, L. and

Farmera, E.E. (2007) A downstream mediator in the growth repression

limb of the jasmonate. Plant Cell 15: 2866–2884.

(Received November 9, 2007; Accepted November 19, 2007)


Dow



ecember 2021

Documents

to Thrip Feeding - Plant and Cell Physiology