DETERMINATION OF ENDOPHYTIC BACTERIA COMPOSITION OF RICE SEED USING DGGE

Abstract

Endophytic bacteria have a potential role in promoting plant growth and suppressing disease pathogens in a cost effective and environmentally friendly manner. This study was therefore conducted with the aim of determining the endophytic bacteria composition of rice seeds collected in Kenya in view of their agronomic importance. Different varieties of rice seeds were collected from Bunyala, Hola, Kaloleni, Mwea, Msabweni, and Taveta in Kenya. Rice seeds were surface-sterilized and bacterial DNA isolated. Partial 16SrRNA gene was amplified using Denaturing Gradient Gel Electrophoresis (DGGE) primers. Endophytic bacterial gene fragments from five samples of rice seed varieties were successfully amplified. Amplified DNA was then subjected to DGGE and a total of 41 DNA bands were excised from the gel. The excised DNA bands were then re-amplified and 31 out of the 41 PCR products obtained were sequenced for endophytic bacteria identification. Bacteria strains were identified as  Methylobacteriaceae, Sphingomonadaceae,  Enterobacteriaceae,  Pseudomonadaceae,  Flavobacteriaceae  and  Rhizobiaceae. Methylobacterium  species, for example, are very important organisms, which  have been shown to stimulate seed germination and plant development, perhaps through production of phytohormones. The next stage of this study will be to isolate such specific bacterial strains and determine their agronomic importance on rice production in Kenya.