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.

Graphical Abstract

中文翻译：

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芥菜种子悬浮液的种子、上清液和颗粒阶段植物内部细菌的门水平多样性

我们之前的研究通过开发新的分离策略，使用培养依赖性方法探索了一定数量芥菜种子中细菌内生的多样性。芥菜籽悬浮液离心后获得的上清液中最初没有观察到细菌菌落。后来通过使用表面活性剂克服了这一问题，而颗粒部分在培养基上显示出细菌菌落的存在。在我们目前的研究中，通过独立于培养的方法检查了上清液中细菌的存在以及多样性是否与颗粒和种子的多样性相似。此外，使用 GC-MS 解释了培养基上细菌菌落的生长。在本研究中，变形菌门是颗粒、上清液和种子中的优势细菌门，其次是厚壁菌门。这表明细菌存在于上清液中，但在铺板于培养基上时可能无法存活。这要么是由于抗菌化合物，要么是由于石油在分离过程中造成的困难，这可能阻碍了它们的生存。 GC-MS 研究表明存在具有抗菌特性的化合物，正如之前的文献所表明的那样。我们的研究进行基础研究，以实现了解芥菜籽、颗粒和上清液中细菌多样性的主要目标。使用宏基因组学和代谢组学方法的工作流程进行进一步研究可以丰富我们对种子中微生物多样性的理解。

图形概要