Characteristics of <i>Ralstonia solanacearum</i> Strains of Potato Wilt Disease from Nepal and Thailand

Abstract

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&amp;5, 2001/2002Page: 42-47Uploaded date: 9 June, 2011

Biochemical Characterization of <i>Ralstonia solanacerum</i> Causing Bacterial Wilt of Brinjal in Bangladesh

“…Result showed that all the isolates were able to cause rapid death of local cell of tissue between veins of tobacco leaves. These results are in accordance with the findings reported by Dhital et al (2001) who observed that R. solanacearum was able to produce HR in tobacco leaves. These results clearly indicated that like other plant pathogenic bacteria, R. solanacearum isolates possess Hrp type III secretion system which is responsible for inducing HR on tobacco leaves.…”

Determination of Races and Biovars of Ralstonia solanacearum Causing Bacterial Wilt Disease of Potato

“…The isolates were also characterized by the hypersensitive response (HR) test in tobacco and also by different biochemical tests. These results were supported by the findings of Dhital et al (2001) who observed that R. solanacearum was able to produce wilt symptoms in potato, HR in tobacco leaves and was found positive by a series of biochemical tests. Also, the Gram staining and KOH solubility test indicated that the isolates of R. solanacearum are gram negative.…”

Fatty Acid Polymorphism of Ralstonia solanacearum in Different Egyptian Governorates and other European Countries

“…In a host range study, all isolates were high to moderate pathogenic on potato and tomato, whereas on the other Solanaceous hosts such as eggplant and pepper were moderate to low pathogenic. The obtained results were in agreement with earlier reports stating that, characteristic of race 3 of R. solanacearum had limited host range (Buddenhagen et al, 1962;He et al, 1983;French, 1986;Dhital et al, 2001;Ibrahim et al, 2005).…”

“…All plantlets were planted in sterilized pots (20 cm diameter) containing sterilized peat-moss/sand (v/v) and allowed to grow for 6-8 weeks or until they were 15-20 cm high. Roots of each host plants were wounded and dipped in bacterial suspension (10 8 CFU mLG 1 ) of each isolate alone for 20 min and three replicates were used (Dhital et al, 2001). Degree of wilt was calculated according to He et al (1983), as average of three plants at four weeks after inoculation and rating scales were as followed: H, High (disease index 4.1-5.0); M, Moderate (2.6-4.0) and L, Low (1.1-2.5).…”