Bacterial community associated with rhizosphere of maize and cowpea in a subsequent cultivation

Abstract

The rhizosphere is the soil zone influenced by the roots and its characteristics vary according to plant species and their stage of development. These different characteristics can influence the bacterial community inhabiting the rhizosphere niche that, in turn, influences plant growth and health. In this study, the bacterial community dynamics in the rhizosphere of maize and cowpea, in subsequent cultivation, were assessed using the 16S rRNA sequencing. Thus, during maize growth, soils were collected at 45 (flowering) and 75 (senescence) days. Afterward, during cowpea growth, the sampling occurred at 35 (flowering) and 65 (senescence) days. Our results showed differences between developmental stages within the same plant species. For maize, Acidobacteria decreased from flowering to senescence; while for cowpea, Proteobacteria, Armatimonadetes, WPS-2, and OP11 increased from flowering to senescence. Comparing the same developmental stage for both plant species, Proteobacteria, Elusimicrobia, WPS-2 decreased from maize flowering to cowpea flowering; while for the senescence stage, Acidobacteria, Armatimonadetes, and OP11 increased from maize to cowpea. Also, the rhizosphere community dynamic was more complex at the senescence stage compared to the flowering stage and bulk soil for both plants species. The results showed that the structure and diversity of bacterial community vary significantly according to plant species and, in a minor extent, their developmental stage. Also, we showed that the variation in rhizosphere activity during the plant growth could drive the responses of the bacterial community.