A comparative study of bacterial diversity based on culturable and culture-independent techniques in the rhizosphere of maize ( L.).

Objective: Maize is an important crop for fodder, food and feed industry. The present study explores the plant-microbe interactions as alternative eco-friendly sustainable strategies to enhance the crop yield.

Methodology: Bacterial diversity was studied in the rhizosphere of maize by culture-dependent and culture-independent techniques by soil sampling, extraction of DNA, amplification of gene of interest, cloning of desired fragment and library construction.

Results: Culturable bacteria were identified as , , , and genera. For culture-independent approach, clone library of 16S ribosomal RNA gene was assembled and 100 randomly selected clones were sequenced. Majority of the sequences were related to Firmicutes (17%), Acidobacteria (16%), Actinobacteria (17%), Alpha-Proteobacteria (7%), Delta-proteobacteria (4.2%) and Gemmatimonadetes (4.2%) However, some of the sequences (30%) were novel that showed no homologies to phyla of cultured bacteria in the database. Diversity of diazotrophic bacteria in the rhizosphere investigated by analysis of PCR-amplified H gene sequence that revealed abundance of sequences belonging to genera (25%), (10%), (10%). The diazotrophic genera and related H sequences were also detected but no sequence related to was found showing biasness of the growth medium rather than relative abundance of diazotrophs in the rhizosphere.

Conclusion: The study provides a foundation for future research on focussed isolation of the and other diazotrophs found in higher abundance in the rhizosphere.