Biodiversity is an appealing aspect including microorganisms encompasses diverse assemblage of organisms exhibiting with morphological, physiological, biochemical, metabolic and ecological diversity. At the level of taxonomic diversity microorganism signify phenotypic and genotypic diversity. Whereas, phenotypic diversity physiologically diversify the population of bacteria on the other hand, genotypic diversity explore the genetic divergence within the bacterial population. Functional diversity in the rhizosphere in particular is also considered as functional behavior of microbial community in their ecological niche or ecosystem. Functional diversity is the measures of distribution and functional niche of organisms where they remain functional in communities and multi-dimensional cloud of species trait and each trait representing an individual or a species. Most often define biodiversity as the "totality of genes, species, and ecosystems of a region studied under term species diversity, genetic diversity and ecological diversity." Microbial diversity in rhizosphere bears several interactions and controls the functional roles to permit parse and plant survival. Measurement of biodiversity on species richness and evenness/dominance indices, species abundance models is recent tools to assess microbial diversity. Rhizosphere implicit microbial population aids benefits for plants in term of growth promotion and proved itself as important and putative communities for increased crop productivity.
IntroductionThe term biodiversity was used first by Wilson (1988). Since then the concept of biodiversity continuous spread to arose as developing and emerging field. Biodiversity is defined as the variety of living organisms at species, inter-species and intraspecies level in ecology which is much considered in terms of plants and animals; yet, the assortment of microbial life forms a huge and largely uncharted account. Microorganisms are quite beneficial and exploited in gain of quite lot revenue for D. K. Maheshwari et al. 2 humankind and earth's ecology. Similarly, as the plants and animals are conserved to counter the alarm of extinction of their species, the great reservoir of rhizospheric microbial diversity, employed for ecological and humankind services should be conserved in the means of culture collection and genomic library construction and utilization in agriculture. Such appealing organisms having distributional merit in all three dimensions of nature and ecology viz., soil, water and air, where microbial diversity signify at distinct ecological levels. The soil is a reservoir and prime nutritional habitat of severe community of phenotypic and genotypic diverse microorganisms. It is daunting task to grasp considerate of microbial diversity so, under this quest, it is necessary to group such organisms together so as to organize them in non-overlapping hierarchy. On account of classification system using polyphasic taxonomy i.e., phenotypic, genotypic and phylogenetic classification results diversity a...