Evidence of variability in the structure and recruitment of rhizospheric and endophytic bacterial communities associated with arable sweet sorghum (Sorghum bicolor (L) Moench)

摘要

Sorghum is the second most cultivated crop in Africa and is a staple food source of manyAfrican communities. Exploiting the associated plant growth promoting bacteria (PGPB) haspotential as an agricultural biotechnology strategy to enhance sorghum growth, yield andnutritional properties. Here we use Terminal-Restriction Fragment Length Polymorphism (TRFLP)and Denaturing Gradient Gel Electrophoresis (DGGE) to evaluate the factors thatpotentially shape rhizospheric and endophytic bacterial communities associated with sorghumfarmed in South Africa. Microbial diversity was typically higher in the rhizosphere andrhizoplane compared to the endophytic zones (root, shoot and stem). Geographical locationwas one of the main drivers in describing microbial community assemblages found inrhizospheric and endophytic sorghum-linked niches. NO3-N, total nitrogen and pH wereclearly identified as the main abiotic factors shaping sorghum-associated soil communities.Our results also suggest that specific bacterial taxa with potential N-fixing capacities(Acetobacter sp., Azospirillum sp., Pantoea sp., Bacillus sp. and cyanobacteria) areconsistently detected in sorghum-created rhizospheric and endophytic environments,irrespective of environmental factor effects.