Analysis of the bacterial and fungal community profiles in bulk soil and rhizospheres of three mungbean [Vigna radiata (L.) R. Wilczek] genotypes through PCR-DGGE

Each plant species is regarded to substantially influence and thus, select for specific rhizosphere microbial populations. This is considered in the exploitation of soil microbial diversity associated with important crops, which has been of interest in modern agricultural practices for sustainable productivity. This study used PCR-DGGE (polymerase chain reaction - denaturing gradient gel electrophoresis) in order to obtain an initial assessment of the bacterial and fungal communities associated in bulk soil and rhizospheres of different mungbean genotypes under natural field conditions. Integrated use of multivariate analysis and diversity index showed plant growth stage as the primary driver of community shifts in both microbial groups while rhizosphere effect was found to be less discrete in fungal communities. On the other hand, genotype effect was not discerned but not inferred to be absent due to possible lack of manifestations of differences among genotypes based on tolerance to drought under non-stressed environment, and due to detection limits of DGGE. Sequence analysis of prominent members further revealed that Bacillus and Arthrobacter species were dominant in bacterial communities whereas members of Ascomycota and Basidiomycota were common in fungal communities of mungbean. Overall, fungal communities had higher estimated diversity and composition heterogeneity, and were more dynamic under plant growth influence, rhizosphere effect and natural environmental conditions during mungbean growth in upland field. These primary evaluations are prerequisite to understanding the interactions between plant and rhizosphere microorganisms with the intention of employing their potential use for sustainable crop production.