Isolation, screening of growth-promoting activities and diversity of rhizobacteria from vetiver grass and rice plants.

摘要

One hundred thirty six isolates of rhizobacteria were obtained from rhizosphere of different vetiver ecotypes and different rice varieties. Their acetylene reduction activities and indole acetic acid (IAA) producing activities were determined. A wide variation in both nitrogenase (0.01-2.15 n mole C₂H₄ mg-1 protein h-1 and 0.01-8.84 n mole C₂H₄ mg-1 protein h-1 for the first and second screening, respectively) and IAA (0.05-99.59 and 0.00-118.02 g IAA mg-1 protein for the first and second screening, respectively) activities of the isolates was shown. Twenty five promising isolates that have potential to be PGPR were selected on the basis of both high nitrogenase and/or IAA production activities. The diversity of the selected isolates was indicated by 16S rDNA analysis. A total of six clusters of all isolates were represented as follows, Gammaproteobacteria (Order Xanthomonadales), Betaproteobacteria (Order Burkholderiales), Gammaproteobacteria (Order Enterobateriales), Alphaproteobacteria (Order Rhodospirillales), Alphaproteobacteria (Order Rhizobiales) and Endosporobacteria (Order Bacillales).