Un-culturable Microbial Community Analysis of Paddy Ecosystem at Different Depths using Nif H Gene DGGE Analysis Approach
2020
Meurial, C Daphy | Kumar, K.
Biological N² fixation is gaining importance in rice ecosystem, because of current concern on the environmental and soil health that are caused by the continuous use of nitrogenous fertilizers and the need for improved sustainable rice productivity. BNF is the conversion of atmospheric nitrogen by certain microorganism's viz., N² fixing microorganisms or diazotrophs into forms that plants can use. A substantial molecular diversity of N² fixing bacteria has been detected in the rice field soil based on retrieval of nif H gene fragment from DNA by molecular approach, i.e., DGGE (Denaturant Gradient Gel Electrophoresis). The present investigation aimed to assess the diversity of N² fixing bacteria by sequencing and phylogenetic analysis of nif H gene of the metagenomic DNA collected from different depth of flooded rice soil. In this laboratory investigation, soil samples were collected from the paddy field at different depths viz., rhizosphere region, 5 cm, 10 cm, 15 cm depth using the core sampler during active tillering stage. In the laboratory, the collected soil samples were analyzed by molecular methods involving the use of primer sets based on nif H sequences (nitrogenase reductase). Our investigations in the genetic diversity of diazotrophs associated with rice field soil using nif H revealed the existence of seven discrete bands. The sequencing results showed all sequences were classified as uncultured bacterium clone nitrogenase iron protein (nif H) gene, partial cds. The present works based on the applications of molecular methods have facilitated the study of individual ecosystem and their specific activity.
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