Microbial diversity and soil physiochemical characteristic of higher altitude

Abstract

Altitude is the major factor affecting both biodiversity and soil physiochemical properties of soil ecosystems. In order to understand the effect of altitude on soil physiochemical properties and bacterial diversity across the Himalayan cold desert, high altitude Gangotri soil ecosystem was studied and compared with the moderate altitude Kandakhal soil. Soil physiochemical analysis showed that altitude was positively correlated with soil pH, organic matter and total nitrogen content. However soil mineral nutrients and soil phosphorus were negatively correlated to the altitude. RT-PCR based analysis revealed the decreased bacterial and diazotrophic abundance at high altitude. Metagenomic study showed that Proteobacteria, Acidobacteria and Actinobacteria were dominant bacteria phyla at high altitude soil while Bacteroidetes and Fermicutes were found dominant at low altitude. High ratio of Gram-negative to Gram positive bacteria at Gangotri suggests the selective proliferation of Gram negative bacteria at high altitude with decrease in Gram positive bacteria. Moreover, Alphaproteobacteria was found more abundant at high altitude while the opposite was true for Betaproteobacteria. Abundance of Cytophaga, Flavobacterium and Bacteroides (CFB) were also found comparatively high at high altitude. Presence of many taxonomically unclassified sequences in Gangotri soil indicates the presence of novel bacterial diversity at high altitude. Further, isolation of bacteria through indigenously designed diffusion chamber revealed the existence of bacteria which has been documented in unculturable study of WIH (Western Indian Himalaya) but never been cultivated from WIH. Nevertheless, diverse functional free-living psychrotrophic diazotrophs were isolated only from the high altitude Gangotri soil. Molecular characterization revealed them as Arthrobacter humicola, Brevibacillus invocatus, Pseudomonas mandelii and Pseudomonas helmanticensis. Thus, this study documented the bacterial and psychrophilic diazotrophic diversity at high altitude and is an effort for exploration of low temperature bacteria in agricultural productivity with the target for sustainable hill agriculture.

Phosphate-Solubilizing Microorganisms: Mechanism and Their Role in Phosphate Solubilization and Uptake

“…DNA reassociation technique is an important molecular tool to make comparisons and calculate similarities between genomes of different microorganisms. Genetic similarity of diverse PSMs is studied using this method (Kumar et al 2019;Mahato et al 2017). Fatty acid methyl esters (FAME) analysis method is used for identification and determination of species.…”

Geology and climate influence rhizobiome composition of the phenotypically diverse tropical tree Tabebuia heterophylla

“…Indeed, studies have observed greater environmental fluctuations in low altitude sites, whereas high altitude sites have normally lower temperature, nutrient, and water availability [39][40][41]. Indeed a recent study found selective proliferation of Gram negative bacteria at high altitude, including psychrophilic diazotrophs, along with a decrease in Gram positive bacteria [41], however these studies were done at significantly higher altitudes than those assessed in this manuscript.…”

“…These differences in the microbial communities can be ascribed to differences in the environmental conditions at the different altitudes, emphasizing the importance of variables such precipitation and temperature, as previously shown in other geographical studies [37,38]. Indeed, studies have observed greater environmental fluctuations in low altitude sites, whereas high altitude sites have normally lower temperature, nutrient, and water availability [39][40][41]. Indeed a recent study found selective proliferation of Gram negative bacteria at high altitude, including psychrophilic diazotrophs, along with a decrease in Gram positive bacteria [41], however these studies were done at significantly higher altitudes than those assessed in this manuscript.…”

Microbial Ecology from the Himalayan Cryosphere Perspective

“…The existing studies from different regions of Himalaya show the complicated composition of microbial communities [28][29][30][31][32] and diverse metabolic potential [27,33,34] through various culture-dependent and culture-independent methods. In the last two decades, a lot of information associated with the microbial communities of Himalaya has been generated.…”

“…Only few studies are dedicated to the distribution of fungi in the Himalayan region, indicating the significantly high abundance of Ascomycota [5,36,37]. The investigations on these inhabiting micro-eukaryotes are now increasing continuously [29,38,39] because of their high bioprospection values in agriculture and other biotechnology-based industries [27].…”