Root nodules offer habitat not only for Rhizobium also for a wide variety of endophytic bacteria that have a positive impact on growth and nutrient status of the plant. To evaluate this statement, the present study was aimed to reveal the cultivable Rhizobium (R) and passenger endophytes (PE) of groundnut nodule and explored their impact on plant growth parameters. Two groundnut phenotypes, bunch (cv., VRI 2) and semi-spreading (cv., VRI 7) varieties nodule were collected for isolation of endophytes. Molecular characterization of nodule endophytic bacterial isolates were done using 16S rDNA sequencing. Isolates were screened based on their early plant growth promotion and selected efficient R and PE were co-inoculated to assess the impact on plant growth. Ninety eight nodule endophytic bacterial isolates were distributed among the Firmicutes, Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. In bunch type groundnut (VRI 2) co-inoculation of Rhizobium phaseoli S18 and Pantoea dispersa YBB19B registered significantly higher shoot length, root length, dry weight and nodule number. Similarly, in semi-spreading groundnut (VRI 7) co-inoculation of Rhizobium mayense S19 with Kosakonia oryzae ESB1 recorded maximum shoot length, root length, dry weight and nodule number. R and PE in nodules are visualized in SEM micrograph and changes in root exudates composition as a result of endophytic bacteria inoculation was assessed through GC-MS. This study showed that the nodule endophytic bacterial diversity of groundnut is vast and co-inoculation of native R and nodule PE significantly improved the plant growth than that of Rhizobium alone.

根瘤不仅为根瘤菌提供了栖息地，而且还为多种内生细菌提供了栖息地，这些内生细菌对植物的生长和营养状况产生了积极影响。为了评估这一说法，本研究旨在揭示可培养的根瘤菌根瘤的（R）和过客内生菌（PE），并探讨了它们对植物生长参数的影响。收集了两个花生表型，一堆（cv。，VRI 2）和半蔓延（cv。，VRI 7）的结节，以分离内生菌。结节内生细菌分离株的分子表征使用16S rDNA测序进行。根据其促进植物早期生长来筛选分离株，并共同接种所选的高效R和PE以评估对植物生长的影响。九十八个结节内生细菌分离物分布在Firmicutes，Alphaproteobacteria，Betaproteobacteria和γproteobacteria中。在束状花生（VRI 2）中接种根瘤菌S18和Pantoea dispersa YBB19B的芽长，根长，干重和根瘤数均显着较高。同样，在半蔓延花生（VRI 7）中，共同接种马氏根瘤菌S19与米草小叶藻ESB1，可记录最大芽长，根长，干重和根瘤数。根瘤中的R和PE在SEM显微镜下可视化，并且通过GC-MS评估了接种内生细菌后根系分泌物组成的变化。这项研究表明，花生的根瘤内生细菌多样性很大，与天然根瘤菌和根瘤菌PE一起接种显着改善了植物的生长。