Morphological and Biochemical Characterization of Strains of Ralstonia solanacearum, Causal Agent of Bacterial Wilt in Tomatoes in Cameroon and Screening of Virulent Strains

Cylvain Patrick Mountseng

Department of Plant Biology and Physiology, Phytopathology and Plant Protection Laboratory, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon.

Hermine Mahot

Institute of Agricultural Research for Development, Yaounde, Cameroon.

Gertrude Membang

Department of Plant Protection, Faculty of Agronomy and Agricultural Sciences, University of Dschang, Cameroon.

Serges Bertrand Mboussi

Laboratory of Biotechnology, University Institute of Technology, University of Douala, Douala, Cameroon.

Didier Begoude

Institute of Agricultural Research for Development, Yaounde, Cameroon.

Zachée Ambang *

Department of Plant Biology and Physiology, Phytopathology and Plant Protection Laboratory, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon.

*Author to whom correspondence should be addressed.


Ralstonia solanacearum is a major constraint in tomato production. The aim of this work was to identify the different biovars and races of R. solanacearum which infect tomato plants in Cameroon and determine the most virulent in a gnotobiotic environment. Thirty (30) samples were collected in the field of 03 different agro-ecological zones considered as major tomato production area in Cameroon. The bacteria were isolated on modified Kelman solid medium, and identified based on morphological and biochemical characterization. The pathogenicity test was performed in a gnotobiotic environment by root inoculation. Twenty-nine (29) isolates showed colonies characteristic of virulent strains. Water, motility, catalase, KOH, Kovac oxidase, glucose reduction, and sucrose tests were positive. However, gram staining, spore production, arginine test and sulfate reduction were negative. The biovar tests carried out revealed the presence16.66% biovar 2 (bv 2) and 76.66% biovar 3(bv 3). The tobacco hypersensitivity tests carried out revealed the presence of two (02) races: race 1 and race 3 (majority). A predominance of race3 biovar 3 was observed in Cameroon. Results from pathogenicity test revealed that two (02) strains, FM6 (race 3 bv2) and BFo (race 3 bv 3) were high virulent, causing up to 100% loss of seedlings on the sixth day post-inoculation.

Keywords: R. solanacearum, tomato, biochemical characterization, virulence

How to Cite

Mountseng, C. P., Mahot , H., Membang , G., Mboussi , S. B., Begoude , D., & Ambang , Z. (2024). Morphological and Biochemical Characterization of Strains of Ralstonia solanacearum, Causal Agent of Bacterial Wilt in Tomatoes in Cameroon and Screening of Virulent Strains. Annual Research & Review in Biology, 39(5), 27–42.


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