Approving the biocontrol method of potato wilt caused by Ralstonia solanacearum (Smith) using Enterobacter cloacae PS14 and Trichoderma asperellum T34

A native Trichoderma isolate was collected from the agricultural soil of Gazipur. This isolate was identified as a Trichoderma asperellum through morphology and analysis of internal transcribed spacer (ITS) region of ribosomal RNA gene sequence and reconstruction of the phylogenetic tree. The antagonistic effects of the newly identified T. asperellum isolate were assessed against brinjal bacterial wilt caused by Ralstonia solanacearum both in vitro and in planta. Both qualitative and quantitative bioassays were conducted in vitro. For qualitative tests, dual culture and antibacterial activity were carried out, and pathogen growth was observed visually. The antagonism of T. asperellum cell free culture filtrate on the growth of R. solanacearum was conducted in a quantitative test. Successful antagonism was recorded after both in vitro qualitative tests. In addition, the lowest colony forming unit was recorded in 100% of CFC (2.4±0.51 ×103 cfu/ml) in quantitative test. The T. asperellum inoculated plant showed low disease incidence (13.33%) when seedlings were challenged with R. solanacearum in planta experiment. Disease incidence was 100% for seedlings when treated with only R. solanacearum. The results showed that the isolated and identified T. asperellum isolate suppressed R. solanacearum growth in vitro and protected the seedling from wilting in planta. Therefore, this isolate could be considered as a potential isolate. Ann. Bangladesh Agric. (2020) 24(2) : 107-120

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Characteristics of Ralstonia solanacearum Strains of Potato Wilt Disease from Nepal and Thailand

Nepal Agriculture Research Journal ◽

10.3126/narj.v4i0.4868 ◽

1970 ◽

pp. 42-47 ◽

Cited By ~ 1

Author(s):

Shambhu P Dhital ◽

Nanda Thaveechai ◽

Sundar K Shrestha

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Hypersensitive Reaction ◽

Wilt Disease ◽

Pathogenicity Test ◽

Serological Tests ◽

Bacterial Wilt Disease ◽

Research Journal ◽

Limited Host Range ◽

Potato Wilt

Characterization of strains of Ralstonia solanacearum, the causal agent of potato bacterial wilt disease from Nepal and Thailand was performed based on pathogenicity, biochemical/physiological and serological tests. Fifteen R. solanacearum strains isolated from wilt infected potato plants and tubers grown in Nepal were characterized as race 3, biovar II based on the pathogenicity on different host plants, hypersensitive reaction on tobacco leaf and utilization of some sugars. Results of pathogenicity test show that all strains from Nepal had limited host range. Degree of virulence of all strains varied from high to medium in potato and tomato and medium to low in eggplant. They did not cause wilting in tobacco, pepper and peanut plants. Six strains from Thailand were characterized as biovar II and III. Additionally, comparisons on the physiological, biological and serological characters of seven strains from Nepal and six from Thailand revealed similar characters. Race 3 and biovar II of the pathogen was widely spread over potato growing areas of mid and high hills of Nepal. Both biovars II and III were prevalent in the potato growing areas of Thailand but biovar III was the most dominating one.Key words: Bacterial wilt; Potato; Pseudomonas solanacearum; Ralstonia solanacearumDOI: http://dx.doi.org/10.3126/narj.v4i0.4868Nepal Agriculture Research Journal Vol. 4&5, 2001/2002Page: 42-47Uploaded date: 9 June, 2011

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Role of Trehalose Synthesis in Ralstonia syzygii subsp. indonesiensis PW1001 in Inducing Hypersensitive Response on Eggplant (Solanum melongena cv. Senryo-nigou)

The Plant Pathology Journal ◽

10.5423/ppj.oa.06.2021.0087 ◽

2021 ◽

Vol 37 (6) ◽

pp. 566-579

Author(s):

Nur Laili ◽

Takafumi Mukaihara ◽

Hidenori Matsui ◽

Mikihiro Yamamoto ◽

Yoshiteru Noutoshi ◽

...

Keyword(s):

Stress Tolerance ◽

Hypersensitive Response ◽

Ralstonia Solanacearum ◽

Solanum Melongena ◽

Ion Leakage ◽

Solanum Torvum ◽

Osmotic Stress Tolerance ◽

Mutant Strains ◽

Potato Wilt ◽

Trehalose Synthesis

Ralstonia syzygii subsp. indonesiensis (Rsi, former name: Ralstonia solanacearum phylotype IV) PW1001, a causal agent of potato wilt disease, induces hypersensitive response (HR) on its non-host eggplant (Solanum melongena cv. Senryo-nigou). The disaccharide trehalose is involved in abiotic and biotic stress tolerance in many organisms. We found that trehalose is required for eliciting HR on eggplant by plant pathogen Rsi PW1001. In R. solanacearum, it is known that the OtsA/OtsB pathway is the dominant trehalose synthesis pathway, and otsA and otsB encode trehalose-6-phosphate (T6P) synthase and T6P phosphatase, respectively. We generated otsA and otsB mutant strains and found that these mutant strains reduced the bacterial trehalose concentration and HR induction on eggplant leaves compared to wild-type. Trehalose functions intracellularly in Rsi PW1001 because addition of exogenous trehalose did not affect the HR level and ion leakage. Requirement of trehalose in HR induction is not common in R. solanacearum species complex because mutation of otsA in Ralstonia pseudosolanacearum (former name: Ralstonia solanacearum phylotype I) RS1002 did not affect HR on the leaves of its non-host tobacco and wild eggplant Solanum torvum. Further, we also found that each otsA and otsB mutant had reduced ability to grow in a medium containing NaCl and sucrose, indicating that trehalose also has an important role in osmotic stress tolerance.

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Phylogenetic Diversity Analysis of Ralstonia solanacearum, Pseudomonas fluorescens and Trichoderma asperellum Isolated from Tomato Rhizosphere Soil in Karnataka

International Journal of Current Microbiology and Applied Sciences ◽

10.20546/ijcmas.2019.803.047 ◽

2019 ◽

Vol 8 (03) ◽

pp. 381-388

Author(s):

K. Soumya ◽

K. Narasimha Murthy ◽

C. Srinivas ◽

S.R. Niranjana

Keyword(s):

Pseudomonas Fluorescens ◽

Ralstonia Solanacearum ◽

Phylogenetic Diversity ◽

Rhizosphere Soil ◽

Diversity Analysis ◽

Trichoderma Asperellum

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Epidemiological analysis of clones and cultivars of potato in soil naturally infested with Ralstonia solanacearum biovar 2

Fitopatologia Brasileira ◽

10.1590/s0100-41582007000300001 ◽

2007 ◽

Vol 32 (3) ◽

pp. 181-188 ◽

Cited By ~ 2

Author(s):

José R.P. Silveira ◽

Valmir Duarte ◽

Marcelo G. Moraes ◽

Carlos A. Lopes ◽

José M. Fernandes ◽

...

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Integrated Management ◽

Solanum Tuberosum L ◽

Area Under The Curve ◽

Latent Infections ◽

Potato Plants ◽

Progress Curve ◽

Race 1 ◽

Potato Wilt

The objectives of this study were to evaluate the progress of Ralstonia solanacearum bacterial potato wilt biovar 2 (race 3) in 14 potato (Solanum tuberosum L.) cultivars or clones, the resistance of potato clone MB 03 (selected in Brasília, Brazil) to race 1 of R. solanacearum, and the occurrence of the pathogen in tubers harvested from asymptomatic potato plants. During the spring (September to the end of November in the southern hemisphere) of 1999 and 2000, 14 cultivars or clones were grown in a field naturally infested with R. solanacearum biovar 2, in Caxias do Sul, RS. The number of wilted potato plants was recorded each week and a disease progress curve plotted, the resistance of the potato genotypes to bacterial wilt being evaluated by determining the area under the curve. Various models were evaluated to fit the curves, with the logistic model being the best fit. At the end of each growing season tubers produced by asymptomatic plants were harvested and stored until budding and then tested for the presence of R. solanacearum. Cultivar Cruza 148 and clone MB 03 were the most resistant but both showed tubers with latent infections. The epidemiological implications of the incidence of R. solanacearum biovar 2 (race 3) in potato crops, as well as the resistance of certain genotypes that may harbor latent infections, are important aspects to be considered in the integrated management of bacterial wilt.

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