Isolation, Characterization and Identification of Endophytic Bacteria in Sugarcane (Saccharum spp. L.) Cultivated on Soils of the Dong Nai Province, Southeast of Vietnam

Abstract

Endophytic bacterial diversity in sugarcane plant cultivated on Latosols and Acrisols of the Eastern of South Vietnam was studied. Sugarcane plant samples were taken in four sites (districts/towns) (Xuanloc, Dinhquan, Vinhc uu and Trangbom) of Dong Nai province. Endophytic bacteria were isolated in LGI medium together with 16S rRNA gene fragments amplified from DNA using eubacterial universal primers (p515FPL and p13B). A total of 27 isolates were isolated on LGI medium and all of them have ability of nitrogen fixation and phosphate solubilization together with IAA biosynthesis but there were 10 isolates having the best characteristics. The sequences from selected endophytic bacteria (10 isolates) showed high degrees of similarity to those of the GenBank references strains (between 98% and 99%). All of them are Proteobacteria (gram-negative bacteria) and 3 isolates belonged to Alpha-proteobacteria (30%), 2 isolates were Beta-proteobacteria (20%), 5 isolates were Gamma-proteobacteria (50%). Based on Pi value (nucleotide diversity), Gamma-proteobacteria group had the highest theta values and Theta values (per sequence) from S of SNP for DNA polymorphism were calculated for each group and Gamma-proteobacteria group had the highest values in comparison of two groups. From these results showed that Enterobacter oryzae LT7, Achromobacter xylosoxidans T16, Achromobacter insolitus R15b and Pantoea agglomerans T12 revealed promising candidates with multiple beneficial characteristics and they have the potential for application as inoculants or bio-fertilizer adapted to poor latosols and acrisols because they are not only famous strains but also are safety strains for sustainable agriculture.