Diversity Studies of Xanthomonas citri pv. malvacearum Strains Isolated from Cotton in Western Kenya Based on Rep PCR Analysis
##article.abstract##
Cotton or Gossypium L. is an important fibre crop in the world. Prior to the 1990s, the cotton industry in Kenya used to be strong and it remains a very important cash crop to date. During the marketing year 1984/1985, annual yields as high as 70,000 bales of lint were reached. The 1990s was characterized with liberalization of the sector which resulted in near collapse of the sector. Production dropped significantly due to both biotic and abiotic factors. Cotton suffers from bacterial blight (BB), incited by Xanthomonas citri pv. malvacearum (Xcm) and is a key challenge facing the sector. It is an important disease with economic significance throughout all cotton growing areas in the world with lint yield losses ranging from 5- 35%. Cotton leaves clearly showing symptoms of BB infection were collected from the fields in Siaya and Busia of western Kenya. The leaves were first dried and necrotic parts were excised from the infected leaves and soaked in a bleach to kill the fungi. The treated lesions were cultured on nutrient agar (NA) at 26 °C. From the bacterial growth around the lesions, morphologically distinct colonies were taken and streaked on separate NA plates. Two freeze-dried Xcm cultures provided by BCCMTM/LMG were also used as a reference strains.40 Xcm bacterial isolates obtained were then analyzed by rep-PCR of BOX and ERIC (Enterobacterial Repetitive Intergenic Consensus)-PCR fingerprinting to determine the diversity of the Xcm bacteria collected from Siaya and Busia in Western Kenya based on principal component analysis (PCA). The analysis indicated there is sufficient diversity among the field isolates but there exists low molecular variance between Busia and Siaya populations of bacteria based on ERIC and BOX PCR analysis
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