The quantitative assessment of rhizospheric microflora through qPCR based approach in the stubble burning agricultural fields of Madhya Pradesh

Abstract

The world relies on the staple food crops, including wheat, rice and maize for satisfying the daily needs. In India the majority of citizens depend on agriculture for their primary source of income. In terms of production of wheat in the world, India holds the second position. With large amount of production comes ample crop residues also, and stubble is one of them. Rhizosphere which is the quothot spotquot for soil microorganisms is directly connected with the stubble via roots. Stubble burning affects the growth of microorganisms in topsoil especially. The results are evident in showing deleterious impacts of stubble burning on soil microorganisms. Colony forming units (cfu) counts in after burning samples decreased for both bacteria and fungus. The overall results showed average before burning cfu count as 2.03 × 108 cells/gram of soil. However, after burning average cfu count came as 2.96 × 107 cells/gram of soil for bacteria. Likewise, for fungi cfu count decreased from 5.61 × 104cfu/gram of soil to 2.65 × 104cfu/gram of soil. Statistical analysis showed P value=lt0.0001 for bacterial viable cells in all four regions of sample collection and for fungal cfu count only the region of Malakhedi had non-significant results. qPCR assays calculated the concentration of DNA in BB, AB and Co samples. DNA concentrations decreased for total bacterial, total fungal, Pseudomonas spp. and Trichoderma spp. in maximum AB samples. Significant results (P=lt0.05) showed reduction in viable microbial cells due to stubble burning. Concentration of DNA was obtained in ng/µl and there were 11 AB samples (for total bacteria), 17 AB samples (for total fungi), 12 AB samples (for Pseudomonas) and 14 AB samples (for Trichoderma) where no quantifiable amount of DNA was procured in AB samples. The qPCR results were in accordance with microbiological plating tests performed. A comparative analysis of BB, AB and CO soil samples revealed differences in mean values of BB and AB samples significantly.