Optimization of high-yielding protocol for DNA extraction from the forest rhizosphere microbes

Soil is major reservoir for microbes and harbors a vast microbial diversity. Soil microbiota plays a pivotal role in biogeochemical cycles, bioremediation, and in health and disease states of humans, animals, and plants. It is imperative to understand the microbial signatures which are specific in such an ecosystem to unravel their potential role and impact on environment. During the recent years, exploration of soil microbial communities has been geared up with the advent of advanced sequencing technologies. Introduction of custom-made protocols and optimized procedures have enhanced the accuracy levels along with cost-effectiveness of DNA extraction. Standardization of DNA extraction method from soil microbiota has its own limitations due to different nature of soils and the complexity of ecosystems. Though a few standardized protocols are in usage, huge variations and complexities among the microbial communities frequently suggest the optimization, based on various known and unknown factors. Therefore, a set of four standardized DNA isolation protocols was comparatively analyzed with respect to our custom-made protocol owing to the scientific fact that the same protocol does not hold good for all soil samples. Furthermore, the developed protocol has been successfully applied for the identification of efficient plant-specific Rhizobial stains for five legume plants from the soils of various locations under same geographical region. Out of 40 Badrachalam forest soils, five samples, KPFS36, CHFS17, TPFS33, GVFS06, and GPFS40, one for each of Arachis hypogaea, Vigna radiata, Vigna mungo, Glycine max, and Cicer arietinum plants, were selected, respectively, for the soil DNA extraction. A considerable improvement in the DNA yield was identified using the modified protocol with a yield of 21.08 μg/g providing abundant DNA fragments for further investigation on Rhizobial species.