Characterization of Ralstonia

solanacearum in Louisiana for the

Future Development of Novel

Bacterial Wilt of Tomato Management

Programs for Louisiana Producers

Alejandra Jimenez and Melanie Ivey

2015

Department of Plant Pathology and Crop Physiology,

LSU AgCenter, Baton Rouge

Ralstonia solanacearum

Bacterial wilt of tomato

Soil borne pathogen

Broad host range

Considered a species complex

Reported in tropical, subtropical and temperate

regions around the world

Symptoms and Signs

Slow growth or

stunting, yellowing,

and sudden wilt

followed by rapid

death

Brown discoloration

of the vascular

system

Bacterial streaming

Ralstonia solanacearum: Importance

Can cause severe economic losses to tomato

growers in Louisiana

Survival and dissemination

Traditional management tactics are ineffective

Resistance varieties lack durability and have

unfavorable horticultural traits such as small

fruit

Core- TEP

Worldwide genetic diversity of the resistances

available

• 10 Tomato

• 10 Eggplant

• 10 Pepper

Lebeau et al., 2011

Evaluation of worldwide collection of resistant tomato,

eggplant and pepper lines against South Asian strains of R.

solanacearum

37 host lines

– 30 Core-TEP

– Seven strains from South Asia

and Africa

Experiment design

– Plantation

– Inoculation

• Six genetically different SA isolates

– Evaluation

Subedi, N. and Miller, S., 2014

Resistance against South Asian Strains

Subedi, N. and Miller, S., 2014

Resistance against South Asian Strains

Highly

resistant

(0-5%)

Moderately

resistance

(6-20%)

Partially

resistance

(21-40%)

Susceptible

(41-60%)

Highly

susceptible

(61-100%)

TOMATO 5 1 4 1 2

EGGPLANT 7 2 3 0 2

PEPPER 2 3 2 3 0

TOTAL 14 6

Subedi, N. and Miller, S., 2014

Bacterial wilt disease incidence of grafted and non-

grafted heirloom tomato in naturally infested fields

NCSU campus

using the tube grafting

technique (Rivard and

Louws, 2006).

Scion: German Johnson

Grafting tomato to manage bacterial wilt

caused by Ralstonia solanacearum in the

southeastern United States.

Rivard, C. et al., 2012.

NCSU

Sampson

County

Jackson County

Henderson County Scion: ‘Celebrity’ and

‘Mountain Fresh’

In Florida, race 1 (biovar I, phylotype II) strains of Ralstonia

solanacearum has been reported to cause more than 80% yield loss

in field tomato production under disease favorable conditions

Spring 2015

11 isolates

Bacterial wilt was confirmed using the bacterial

streaming test and R. solanacearum-specific

Immunostrips (Agdia Inc.)

Following isolation, all isolates were identified

as R. solanacearum, phylotype II, Biovar 1 or

Biovar 2.

Bacterial Colonies Biovar test

Genetic fingerprinting technique

Eric PCR

100

200

300400

500

1 kb plus

650850

1000

1600

Selective Agent

None of the isolates were Race3 biovar2 based on the

result from R3bv2-specific PCR.

Race 3 biovar 2 is listed as a select agent by

the USDA Agricultural Bioterrorism Protection

Act of 2002.

1 kb plus

307

200300

100

Grafting with resistant rootstocks may be an

effective strategy for managing bacterial wilt in

Louisiana

Select Core-TEP

resistant rootstock linesPopular tomato varieties

grown in Louisiana

Grafting to Manage Bacterial Wilt of Tomato

Survey

Acknowledgement Dr. M.elanie L. Lewis Ivey (LSU)

Dr. Sally Miller (OSU) Lab

Dr. Caitilyn Allen (University of Wisconsin-Madison)

Dr. Frank Louws (NCSU)

THANK

YOU!!

Core- TEP

Lebeau et al 2011