4
and associated extracellular polymeric substances (Pointing and Belnap 2012).
Different N-fixing, denitrifying, decomposing, and P-acquisitioning microbes,
which regulate nutrient cycling, occur in the terrestrial ecosystem. These abundant
and diverse microfloras also aid the process of mineralization in the soils and productivity of the crop plants (van der Heijden et al. 2008). Genomic and proteomic
analysis of psychrophiles reveals the secret of its survival in extreme permafrost
soil. The mechanism behind the adaptation is overexpression of cold-shock proteins
that critically regulate protein folding and three-dimensional structures. Gramnegative α-, β-, and γ-proteobacteria (Pseudomonas sp., Vibrio sp.), Flavobacterium,
and gram-positive bacteria (Micrococcus sp., Arthrobactor sp.) are the dominant
microorganisms present under permafrost soil (Amico et al. 2006). Morris reported
that 68.5% of bacteria are microaerobic in nature, having a high affinity for the
cytochrome oxidase gene. Shotgun metagenomic results showed a high percentage
of these bacteria in Puerto Rican rainforest soils in comparison to Michigan agricultural soils and Michigan deciduous forest soils. Still, the unravelling of the processes and factors responsible for the abundance of micro-oxic bacteria in Puerto
Rican rainforest soil is a topic of deep and focused research. Apart from the huge
soil microbial diversity, its utilization in addressing the global problems of food,
feed, nutrition, and energy security is challenging and need special attention. For
the problems arising from dependency on chemical fertilizers and fertilizers, N-NN-rehabilitation strategies based on maintaining microbial flora in the soils could be
viable options (Canfield et al. 2010).
Microbial communities in the soils govern fertility, physicochemical properties,
and balance in ecosystem functioning, which is an essential issue in the changing
climatic era. Global average temperature and greenhouse gas emissions are increasing steadily and, in such conditions, aridity of the soil may increase its contribution
to global CO 2 , CH 4 , and N 2 O emissions from the terrestrial agro-ecosystem (Dubey
et al. 2016b). To cope up with such issues, above- and belowground agriculturally
important microbial communities need to be explored and utilized as necessary
(Abhilash and Dubey 2014; Abhilash et al. 2015; Tripathi et al. 2016b). Moreover,
the response of microorganisms to increasing temperature and elevated concentrations of CO 2 could be essential studies that may reflect shifts in the communities of
Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Acidobacteria caused
by elevated CO 2 concentration (He et al. 2012). For better soil management and
achieving the targets of SDGs, proper understanding about the structure and functions of microbial diversity and its inter- and intra-communications is essential to
regulate soil processes and ecological functioning.
1 Introduction
and associated extracellular polymeric substances (Pointing and Belnap 2012).
Different N-fixing, denitrifying, decomposing, and P-acquisitioning microbes,
which regulate nutrient cycling, occur in the terrestrial ecosystem. These abundant
and diverse microfloras also aid the process of mineralization in the soils and productivity of the crop plants (van der Heijden et al. 2008). Genomic and proteomic
analysis of psychrophiles reveals the secret of its survival in extreme permafrost
soil. The mechanism behind the adaptation is overexpression of cold-shock proteins
that critically regulate protein folding and three-dimensional structures. Gramnegative α-, β-, and γ-proteobacteria (Pseudomonas sp., Vibrio sp.), Flavobacterium,
and gram-positive bacteria (Micrococcus sp., Arthrobactor sp.) are the dominant
microorganisms present under permafrost soil (Amico et al. 2006). Morris reported
that 68.5% of bacteria are microaerobic in nature, having a high affinity for the
cytochrome oxidase gene. Shotgun metagenomic results showed a high percentage
of these bacteria in Puerto Rican rainforest soils in comparison to Michigan agricultural soils and Michigan deciduous forest soils. Still, the unravelling of the processes and factors responsible for the abundance of micro-oxic bacteria in Puerto
Rican rainforest soil is a topic of deep and focused research. Apart from the huge
soil microbial diversity, its utilization in addressing the global problems of food,
feed, nutrition, and energy security is challenging and need special attention. For
the problems arising from dependency on chemical fertilizers and fertilizers, N-NN-rehabilitation strategies based on maintaining microbial flora in the soils could be
viable options (Canfield et al. 2010).
Microbial communities in the soils govern fertility, physicochemical properties,
and balance in ecosystem functioning, which is an essential issue in the changing
climatic era. Global average temperature and greenhouse gas emissions are increasing steadily and, in such conditions, aridity of the soil may increase its contribution
to global CO 2 , CH 4 , and N 2 O emissions from the terrestrial agro-ecosystem (Dubey
et al. 2016b). To cope up with such issues, above- and belowground agriculturally
important microbial communities need to be explored and utilized as necessary
(Abhilash and Dubey 2014; Abhilash et al. 2015; Tripathi et al. 2016b). Moreover,
the response of microorganisms to increasing temperature and elevated concentrations of CO 2 could be essential studies that may reflect shifts in the communities of
Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Acidobacteria caused
by elevated CO 2 concentration (He et al. 2012). For better soil management and
achieving the targets of SDGs, proper understanding about the structure and functions of microbial diversity and its inter- and intra-communications is essential to
regulate soil processes and ecological functioning.
1 Introduction