Plant Growth Stage Drives the Temporal and Spatial Dynamics of the Bacterial Microbiome in the Rhizosphere of Vigna subterranea

Abstract

Bambara groundnut (BGN) is an underutilized legume commonly found in sub-Saharan Africa. It thrives in marginal soils and is resistant to drought stress. Several studies have been carried out on the nutritional properties of BGN, but very little is known about the effects of plant growth changes and development on rhizosphere bacterial dynamics and function. This study reports on the bacterial dynamics and function in the bulk and rhizosphere soils of BGN at different growth stages (vegetative, flowering, pod-filling, and maturation stages). Aside from the maturation stage that shows distinct community structure from the other growth stages, results obtained showed no significant differences in bacterial community structure among the other growth stages. At a closer level, Actinobacteria, Proteobacteria, and Acidobacteria were dominant in rhizosphere soils at all growth stages. The bulk soil had the least average phyla abundance, while the maturity stage was characterized by the highest average phyla abundance. Rubrobacter, Acidobacterium, and Skermanella were the most predominant genus. It was observed from the analysis of operational taxonomic units that there was significant change in the bacterial structure of the rhizosphere with a higher abundance of potential plant growth-promoting rhizobacteria, at the different growth stages, which include the genera Bacillus and Acidobacterium. Biomarker analysis revealed 7 and 4 highly significant bacterial biomarkers by linear discriminant analysis effect size and random forest analysis at the maturation stage, respectively. The results obtained in this study demonstrated that the bacterial communities of BGN rhizosphere microbiome dynamics and function are influenced by the plant’s growth stages.

All Set before Flowering: A 16S Gene Amplicon-Based Analysis of the Root Microbiome Recruited by Common Bean (Phaseolus vulgaris) in Its Centre of Domestication

“…Generalizations concerning the putative effects are less straightforward for this genus than for, e.g., Rhizobium, because Stenotrophomonas isolates from soil or rhizosphere samples can comprise plant-and human pathogenic strains as well as plant-growth-promoting species [93][94][95]. Nevertheless, the taxonomic affiliations of the dominant OTUs indicate that the ontogenetic shifts in the common bean rhizosphere are likely to generate favourable effects for the plant, similar to a recent report on increasing abundances of growth-promoting bacteria over the ontogeny of the legume Vigna subterranea [96]. The observation that the strongest changes in root microbiota are usually associated with phases of particularly rapid growth and high N demand [37,86] is frequently interpreted as evidence that plants can select or 'filter' microbial communities according to their own, specific needs [4,86].…”

Bambara Groundnut Rhizobacteria Antimicrobial and Biofertilization Potential

“…This shows that biofertilization improved the soil composition, so that minerals were easily made available to plants and then plant growth and crop yield were enhanced. The ability of the Bacillus isolates to increase bambara groundnut growth could be as a result of the PGP potentials of the isolates ( Laili and Antonius, 2017 , Ajilogba et al, 2022a , b ; Ajilogba and Babalola, 2019 ). They were able to solubilize phosphate and produce indole acetic acid, ammonia, and hydrogen cyanide.…”

“…Soil samples were collected from field trials during the planting period between October 2014 and March 2016 from the North-West University Agricultural Farm, Mafikeng Campus (Lat., 25°78′91″ Long., 25°61′84″) Mafikeng, South Africa according to Ajilogba and Babalola (2019) and Ajilogba et al (2021 , 2022b) .…”

Carbon source utilization pattern of soil bacterial microbiome of bambara groundnut rhizosphere at the different growth stages determines soil fertility

“…Growth stages in Bambara groundnut can be categorized into 4 stages (vegetative, flowering, pod-filling, and maturation stages) (Ajilogba et al, 2022c). After 7-15 days of planting it germinates.…”

“…After 7-15 days of planting it germinates. This is followed by flowering which is between 4 and 8 weeks (30-55 days) and may continue throughout the plant's life (Ajilogba et al, 2022c). For nodule formation in bambara groundnut, the flowering stage is critical.…”