Phylum Level Diversity of Plant Interior Bacteria in Seeds, Supernatant and Pellet Phases of Seed Suspension of Mustard Plant

Our previous study explored the bacterial endophytic diversity in a certain quantity of mustard seeds using culture dependent method by development of new isolation strategies. No bacterial colony was initially observed in supernatant obtained after centrifugation of mustard seed suspension. This was later overcome by usage of surfactant whereas pellet part showed presence of bacterial colonies on media. In our present study, presence of bacteria was examined in supernatant and whether the diversity was similar to that of pellet and seeds by culture independent approach. In addition, growth of bacterial colonies on media is explained using GC–MS. In this study, Proteobacteria was the dominant bacterial phyla followed by Firmicutes in pellet, supernatant and seed. This indicated that bacteria were present in supernatant but may not be viable when plated on media. This is either due to antimicrobial compounds or oil-imposed difficulty during their isolation which might have hindered their survival. GC–MS study revealed the presence of compounds with antimicrobial property as suggested by previous literature. Our research conducts fundamental investigations to address the primary objective of understanding the bacterial diversity in mustard seed, pellet, and supernatant. Further research using workflows of metagenomics and metabolomics approaches can enrich our understanding ofthe diversity of microorganisms in seeds.