Our objective in this study was to analyze the structure of the rhizobacterial community during different growth stages of peanut and maize plants. Microcosm assays were performed using pots containing unsterile soil from the peanut growing area of Argentina in which peanut and maize plants were grown during 120 and 100 days, respectively. Four to five samples of rhizospheric soil were obtained at the beginning of the assay, at an early growth stage of each plant and at the end of the assay. Two replicate DNA extractions from rhizospheric soil samples were realized per treatment on both microcosm assays to analyze rhizobacterial community structure by high-throughput sequencing of 16S rRNA gene.

We observed changes in rhizobacteria community structure with crop developmental stages. Community structure changes occurred at several bacteria taxonomic levels, and major changes were observed in later stages. In particular, plant growth promoting bacteria genera were promoted in later stages. Our results indicate plant rhizospheric selection for growth enhancing rhizobacteria during stages of high nutrient demand. In conclusion, the structure of the rhizobacterial communities of peanut and maize are influenced by plant phenological stages, and beneficial bacteria are favoured in late phenological stages.

本研究的目的是分析花生和玉米植物不同生长阶段的根际细菌群落结构。使用装有来自阿根廷花生种植区的未消毒土壤的盆进行微观分析，其中花生和玉米植株分别在 120 天和 100 天内生长。在测定开始时、在每株植物的早期生长阶段和在测定结束时获得四到五个根际土壤样品。在两种微观分析中，每次处理都从根际土壤样品中提取两次重复的 DNA，通过 16S rRNA 基因的高通量测序来分析根际细菌群落结构。

我们观察到根际细菌群落结构随作物发育阶段的变化。群落结构发生在几个细菌分类学水平上，并且在后期观察到了重大变化。特别是在后期促进了植物生长促进细菌属。我们的结果表明，在高营养需求阶段，植物根际选择促进根际细菌的生长。综上所述，花生和玉米的根际细菌群落结构受植物物候阶段的影响，有益菌在物候晚期受青睐。