Isolation and Identification of Rhizospheric Bacteria in Sugarcane (Saccharum spp. L.) Cultivated on Acrisols and Ferrasols of Dong Nai Province, the Southeast of Vietnam

Abstract

doi: 10.11648/j.ajls.20150302.18 Abstract: Nitrogen-fixing and phosphate-solubilizing bacterial diversity and population dynamics in the Acrisol and Ferrasol rhizosphere of sugarcane grown in Dong Nai province, the eastern of South Vietnam was studied. Soil rhizosphere samples were taken in three districts (sites) of this region. Physical and chemical characteristics of soil samples and total nitrogen-fixing and phosphate-solubilizing bacteria counts were determined by drop plate count method together with 16S rRNA gene fragments amplified from DNA using eubacterial universal primers (27F and 1492R). A total of 31 isolates were isolated on two media (Burk’s N-free and NBRIP) and all of them have ability of nitrogen fixation and phosphate solubilization together with IAA biosynthesis. Population of nitrogen-fixing and phosphate-solubilizing bacteria correlated with N total concentration and organic matter content in soil closely (P<0.05). The sequences from selected nitrogen-fixing and phosphate-solubilizing bacteria (12 isolates) showed high degrees of similarity to those of the GenBank references strains (between 98 % and 99%). From 12 isolates, 7 belonged to Bacilli, while 2 were Beta-Proteobacteria, 1 was Acidobacteria and 2 were Bacteroides. Based on Pi value (nucleotide diversity), Bacilli group had the highest theta value and Theta value