Abstract:
Sorghum is the second most cultivated crop in Africa and is a staple food source of many
African communities. Exploiting the associated plant growth promoting bacteria (PGPB) has
potential as an agricultural biotechnology strategy to enhance sorghum growth, yield and
nutritional properties. Here we use Terminal-Restriction Fragment Length Polymorphism (TRFLP)
and Denaturing Gradient Gel Electrophoresis (DGGE) to evaluate the factors that
potentially shape rhizospheric and endophytic bacterial communities associated with sorghum
farmed in South Africa. Microbial diversity was typically higher in the rhizosphere and
rhizoplane compared to the endophytic zones (root, shoot and stem). Geographical location
was one of the main drivers in describing microbial community assemblages found in
rhizospheric and endophytic sorghum-linked niches. NO3-N, total nitrogen and pH were
clearly 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) are
consistently detected in sorghum-created rhizospheric and endophytic environments,
irrespective of environmental factor effects.
