Identification and Characterisation of Endophytic Bacteria in Rice Bean (Vigna umbellata)

Rice bean (Vigna umbellata) is an underutilised legume with unexplored endophytic microbiome. Identification and characterisation of these endophytes are critical in understanding their roles in plant’s growth, health, and productivity. In this study, twelve morphologically and biochemically distinct bacterial endophytes were isolated from rice bean roots. Sequence analysis of the 16S rDNA of the isolates revealed that members of Proteobacteria, including Stenotrophomonas sp., Shinella sp., Roseomonas sp., Pantoea dispersa, and Serratia marcescens dominated the root tissues of rice bean. The remaining isolates were found to be members of Actinobacteria, Bacteroidetes, and Firmicutes. The in vitro assays showed the potential abilities of the endophytic Stenoprophomonas sp., Shinella sp., Microbacterium gilvum, Serratia marcescens, and Bacillus qingshengii in indole acetic acid production, exopolysaccharide production, and phosphate solubilisation. Overall findings suggest diverse and potentially multifunctional endophytes in rice bean that can be incorporated into agricultural practices and crop improvement programs.