12:77-84, 2003

(Amaranthus spp., edible amaranth)

(Amaranthaceae)

(A. viridis L.) (A. lividus L.) (A. mangostanus

L.) (A. mangostanus L. forma ruber Makino)

(A. hypochondriacus L., A.

caudatus L.)

(18 - 23 )

(40 )(1,4) 22 - 30

Albugo bliti

(Biv.) Kuntze (white rust) (5) Pythium spp.

(damping-off) Rhizoctonia solani

(seedling blight) R. solani AG 2-2IIIB

(foliage blight) (3) Albugo bliti

(sori)

(2)

Albugo bliti (Stramenopila)

(Peronosporales) (6,10)

(zoosporangia) (zoospores)

(oospores)

(vesicle)

(indirect germination)

(cyst)

(direct germination)(8,11,13)

(8)

(12) 8 - 12 hr

(haustoria) (9,12)

A. bliti

0% 70%

(Albugo bliti)

1,3 2

1

2

3 mllee@tactri.gov.tw +886-4-23321478

92 4 15

. 2003. (Albugo bliti) .

12:77-84.

Albugo bliti

(Amaranthus mangostanus) (A. mangostanus forma ruber) (A. lividus)

4 4

20 - 40 min

4 hr 12 - 28

20 - 24 32 20 4 hr

36 16 20 3.4%

A. bliti 4

4 hr

( A-C)

Abw, Abr, Abl

1% 30 sec

1 min

50 30 11 cm3 24

4 ( 4

)

4

5 - 7

( D)

V

(90 mm ) 24

1.5 ml

Parafilm "M" (American National CanTM)

(25 )

1 ml

Mini-BeadbeaterTM (Biospec Products) 3000 rmp 1

min

1 105

V

Parafilm "M"

4 - 5

24

2

24 2 hr

(lactophenol cotton blue)

(

A-D) (%) = (

/ ) 100 4 100

- 200 3

(analysis of variance, ANOVA)

4 hr 24

hr

20 min 4 hr

ANOVA

2 hr

5 min

8 - 36 ( 4 ) 4 hr

4 100 - 200

( E, F)

(%) = ( / ) 100

3

32

28

12 2 200378

(Albugo bliti) 79

(A) (B) (C)(Albugo bliti)

(D)Fig. 1. Symptoms of white rust occurred on variousamaranths (A) Amaranthus mangostanus, (B) A. mangostanusforma ruber, and (C) A. lividus caused by Albugo bliti in thefield. (D) Irregular, white protuberant sori on the infected leaf.

( ) ( ) A. B.

C. D.E.

F.= 10 m

Fig. 2. Indirect germination of sporangia and directgermination of zoospores of Albugo bliti. A. sporangia. B.Protuberance on the tip of sporangium. C. Cytoplasmsqueezed from sporangium. D. Zoospores formed within thevesicle outside the sporangium. E. Zoospores swimmingaround the empty sporangium. F. Cyst zoospores germinatedand formed germ tube. Bar = 10 m.

A D

EB

C F

32

(1

105 sporangia/ml) 32 4 24 hr

20 4 hr

20 32

36

4

1.5 ml Parafilm 36

20 4

3 36

16 4

100 - 200 3

JMP version 5 (SAS Inc., Cary, NC,

1989-2002) ANOVA

t test Duncan's new multiple range test

(mean standard

deviation)

Abl

8 hr Abl

2, 4 24 hr 58

18 %, 59 5 %, 65 6% ( )

Abl 24

hr Abl

2

43.8 7.3% 4 66.2

4.4% 14 30.5 5.3%

Y = 30.35 + 9.92 X - 0.71 X2, r2 =

0.92 Y X

( ) 10

t

test

76 31%

64 21%

20 min

10.7 2.9% - 12.1 11.3%

20 240 min Abl Abr Abw

Abl

Abr Abw (p < 0.05) (

)

Abl Abr Abw

80 min 4 hr 56.8

17.4% 64.4 14.4% 39.5 7.0% 37.5 4.1% 32.4

8.6% 39.0 2.6% ANOVA 80

min 4 hr

Abl Abr 12 - 20

20 - 24

32 - 36

( A)

(appressoria) ( )

Abl 12 4 hr

16 - 24

28

Abr

20 - 28 24 - 28

Abr 24

32

Abl, Abr Abw 32

4 hr 24 hr 20 4 hr

32 24 hr

20 32 4 hr 20 4 hr

Abr Abl Abw

Abl, Abr Abw 32 4 hr

20 4 hr 2.0 0.8 %, 1.0 1.4%

1.3 1.5% 69.2 1.5 %, 35.2 1.5% 40.8

2.6% 20 75.0 1.4 %, 12.9 3.8%

24.8 2.9% (p < 0.002) (

A) 32 24 hr 20 4 hr

Abl, Abr Abw 1.3

1.5 %, 2.2 2.5% 1.8 1.5% 25.0 3.7 %,

30.5 2.5% 15.3 9.3% 20 83.5 2.6 %,

26.8 1.8% 44.5 1.7% Abr

Abl Abw (p < 0.001) ( B)

12 2 200380

244 24 hrFig. 3. Zoospore discharge of sporangia of Albugo bliticollected from Amaranthus lividus. Sproangial germinationwas tested with two days intervals after sori formed.Sporangial germination in distilled water was recorded afterincubation at 24 for 4 and 24 hr.

(Abl)24 0, 2, 4, 6, 8, 12,

24 hrFig. 4. Time required for the germination of mature sporangiaof Albugo bliti collected from Amaranthus lividus. Sporangialgermination in distilled water was recorded after incubationat 24 for 2 to 24 hr with 2-hr intervals.

(Albugo bliti) 81

4 hrAbw, Abr AblFig. 5. Sporangial germination of Albugo bliti in distilledwater incubated at 24 for 4 hr with 20-min intervals. Abw,Abr, and Abl were isolates of A. bliti collected fromAmaranthus mangostanus, A. mangostanus forma ruber, A.lividus, respectively.

(Abl) (Abr)(A) (B)

Fig. 6. Effect of temperatures on the sporangial (A) andzoospore (B) germination of Albugo bliti Abl and Abr isolatescollected from Amaranthus lividus and A. mangostanus formaruber, respectively. Sporangial germination in distilled waterafter 4 hr incubation at different temperatures.

24 8 hr(AP) = 10 m

Fig. 7. Appressorium (AP) formed on glass slide afterzoospores in distilled water was incubated at 24 for 8 hr.Bar = 10 m.

36

Abl 36

1 4 20 4 hr

41.0 6.9% 40.6 5.4% t test

10

22.6 5.0%

16 3.4 1.9% ( )

(blastic)

(sporangial chain)

(sporangiophore)

12% t test

AP

AP

12 2 200382

32 AblAbr Abw20, 32 20 32 4 hr 24 hr

32 20 32 4 hr24 hr 20 4 hr

20 32 20 32 p = 0.05Fig. 8. Effect of 32 on the sporangial germination ofAlbugo bliti. Abl, Abr and Abw isolates were A. bliticollected from Amaranthus lividus, A. mangonstanus formaruber, and A. mangonstanus, respectively. 20, 32: sporangialgermination in distilled water was recorded after incubationat 20 and 32 for 4 hr (A) and 24 hr (B), respectively. 32

20: sporangial germination in distilled water was recordedat 32 for 4 hr (A) and 24 hr (B), then transferring to 20for further 4 hr to stimulate the sporangia germination. Thesame letter within the same isolate among the 20, 32 20 and32 treatments, was not differed significantly according tothe Duncan's new multiple range test while p = 0.05.

3636 3

16

p = 0.05Fig. 9. Effect of 36 on the sporangia germination of Albugobliti. Sporangia of A. bliti collected from Amaranthus lividuswere maintained at 36 incubator for 16 days andgermination was tested with 3-day intervals. The same letterabove the bar was not differed significantly according to theDuncan's new multiple range test while p = 0.05.

4 - 5 4 - 6

( )

20 min

Duncan's multiple range test

80 min 24 hr

( )

80

min

24

Edie & Ho (8) (A.

ipomoeae-aquaticae)

25

(30 ) (5)

(25 )

24 2 - 4 hr

Edie & Ho (8) (A. ipomoeae-

aquatice) 15

(Phytophthora

palmivora)(7)

( )

12 - 28 16 - 28 ( )

16 - 24

32 4 hr 24 hr 20

4 hr 32 24 hr

Abr (

B) 32

36

( ) 20 4 hr

24 hr 32

20 20

24 hr

32 6 hr

32 24 hr 4

10 hr ( )

90AS-1.2.2-PI-P4

1. . 1996. .

28: 14-17

2. . 1998. .

40: 439-440 ( )

3. . 2002.

. 11: 33-44

4. . 1981.

.

21:88-105

5. . 1922. (Suborder Peronosporineae)

(Family Albuginaceae) (Genus Albugo).

p. 22-27. 2 .

2 . . 173 pp

6. Barr, D. J. S. 1992. Evolution and kingdoms of organismsfrom the perspective of a mycologist. Mycologia 84:1-11.

7. Clerk, G. C. 1972. Germination of sporangia ofPhytophthora palmivora (Butl.) Butl. Ann. Bot. 36:801-807.

8. Edie, H. H., and Ho, B. W. C. 1970. Factors affectingsporangial germination in Albugo ipomoeae-aquaticae.Trans. Br. Mycol. Soc. 55:205-216.

9. Kajornchaiyakul, P., and Brown, J. F. 1976. The infectionprocess and factors affecting infection of sunflower byAlbugo tragopogi. Trans. Br. Mycol. Soc. 66:91-95.

10. Patterson, D. J. 1989. Stramenopila: Chromophytes froma Protistan Perspective. Pages 357-379 in: TheChromophyte Algae: Problems and Perspectives. J. CGreen, B. S. C. Leadbeater, and W. L. Diver ed. OxfordUniv. Press, New York, 429 pp.

11. Petrie, G. A., and Verma, P. R. 1974. A simple method forgerminating oospores of Albugo candida. Can. J. PlantSci. 54: 595-596.

12. Verma, P. R., Harding, H., Petrie, G. A., and Williams, P.H. 1975. Infection and temporal development ofmycelium of Albugo candida in cotyledons of fourBrassica species. Can. J. Bot. 53: 1016-1020.

13. Verma, P. R., and Petrie, G. A. 1975. Germination ofoospores of Albugo candida. Can. J. Bot. 53: 836-842.

(Albugo bliti) 83

12 2 200384

ABSTRACTLee, M. L. 1,3, and Hsieh, W. H. 2 2003. Effect of temperature on the sporangial germination of Albugo bliti.Plant Pathol. Bull. 12:77-84. (1. Department of Pesticide Application, Taiwan Agricultural Chemicals andToxic Substances Research Institute, Council of Agriculture, Executive Yuan, Taichung hsien, Taiwan,R.O.C.; 2. Department of Plant Pathology, National Chung Hsing Univeristy, Taichung, Taiwan, R.O.C.;3. Corresponding author, E-mail:mllee@tactri.gov.tw, Fax:+886-4-23321478)

The effect of temperature on the discharge of zoospores from sporangia of Albugo bliti (Biv.) Kuntzewas studied. Sporangia of three isolates, Abw from Amaranthus mangostanus L., Abr from Am.mangostanus L. forma ruber Makino, and Abl from Am. lividus L. respectively, were used to inoculate ontheir original host plants. Sori formed on leaves 4 days after inoculation. The highest percentage ofdischarged zoospores was obtained from 4-day-old sori. Zoospores would be quickly discharged within 20-40 min as mature sporangia were incubated in distilled water at 24 , furthermore, the highest amount ofdischarged zoospores could be obtained 4 hr after treatment. The temperatures for sporangia to dischargezoospores ranged from 12 to 28 , while 20 - 24 was optimal. The zoospore discharging capability ofsporangia was inhibited at 32 , which could be partially recovered by subsequently transferring thesesporangia to 20 for 4 hr, and still remained 3.4% at 20 for 4 hr after sporangia were incubatedpreviously at 36 for 16 days, both suggest that A. bliti have already adapted well to the variation oftemperatures in field. Conclusively, in order to undertake a successful inoculation of A. bliti to amaranth,mature sporangia from 4-day-old sori should be used and inoculated leaves should be kept under moistcondition for at least 4 hr.

Keywords: white rust, Albugo bliti, amaranth, temperature, sporangia, germination