Occurence of pectinolytic bacteria causing blackleg and soft rot of potato in Kenya

Jane W Kamau,Jaap Janse,Sospeter Gachamba,Jane Ngaira,Johnson Kinyua,Isaac Macharia,George Ngundo

doi:10.1007/s42161-018-00219-w

Abstract

Potato (Solanum tuberosum) is the second most important crop after maize in Kenya and plays a major role in national food production and security. Despite its importance, production is constrained by a number of factors, including diseases. Diseases caused by bacteria are a major biotic production constraint. Soft rot and blackleg diseases are considered as important constraints causing considerable losses in many production systems. However, there is scanty information on soft rot and blackleg in potato production systems in Kenya. A limited survey was conducted between September and October 2016 and in December 2016 to January 2017 in four major potato growing regions to determine the identity of pectinolytic bacteria causing blackleg and soft rot disease of potato in Kenya. Tubers and stems with symptoms of blackleg and soft rot disease were collected from 91 randomly selected farms. Identification of the pathogens was done using phenotypic methods which involved culturing on semi-selective medium, biochemical tests, pathogenicity tests and DNA based methods. The results identified occurrence of Pectobacterium carotovorum subsp. carotovorum (6 isolates) in all four regions and Pectobacterium wasabiae (5 isolates) for the first time in Elgeiyo Marakwet. The identity of twelve isolates could not be specified and therefore needs further investigation.

Highlights

Potato (Solanum tuberosum) is the second most important crop after maize in Kenya and plays a major role in national food production and security
Kenya is among the top potato producers in Africa where the crop is grown by approximately 500,000 farmers, mainly small-scale farmers, on over 120,000 ha with an average yield of 7.7 tons per hectare (Wang’ombe and Dijk 2013) and plays a major role in national food and nutritional security
Its production is constrained by a number of factors including bacterial diseases such as brown rot caused by Ralstonia solanacearum, and blackleg and soft rot caused by Pectobacterium and Dickeya spp. (Czajkowski et al 2015; Rosenzweig et al 2016)

Summary

Introduction

Potato (Solanum tuberosum) is the second most important crop after maize in Kenya and plays a major role in national food production and security. Its production is constrained by a number of factors including bacterial diseases such as brown rot caused by Ralstonia solanacearum, and blackleg and soft rot caused by Pectobacterium and Dickeya spp. The causal agents for blackleg and soft rot disease of potato in Kenya have not been sufficiently studied.

Results

Conclusion