Diversity and phylogenetic profiling of niche-specific Bacilli from extreme environments of India

Abstract

The diversity of culturable, aerobic and heterotrophic Bacillus and Bacillus-derived genera (BBDG) was investigated in various extreme environments (including thermal springs, cold deserts, mangroves, salt lakes, arid regions, salt pans and acidic soils) of India. Heat treatment followed by enrichment in different media led to a total of 893 bacterial isolates. Amplified ribosomal DNA restriction analysis (ARDRA) using three restriction enzymes AluI, MspI and HaeIII led to the clustering of these isolates into 12-74 groups for the different sites at 75 % similarity index, adding up to 559 groups. Phylogenetic analysis based on 16S rRNA gene sequencing led to the identification of 392 bacilli, grouped in two families, Bacillaceae (89.03 %) and Paenibacillaceae (10.97 %), and included 13 different genera with 75 distinct species. It was found that among the thirteen genera, nine (Bacillus, Halobacillus, Lysinibacillus, Oceanobacillus, Pontibacillus, Salinibacill us, Sedimini bacillus, Thalassobacillus and Virgibacillus) belonged to Bacillaceae and four (Ammoniphilus, Aneurinibacillus, Brevibacillus and Paenibacillus) belonged to Paenibacillaceae. Novel isolates tolerant to low and high pH and temperature, salt and low moisture were identified. The major outcome of the present investigation was the identification of niche-specific species and also the ubiquitous presence of selected species of BBDG, which illustrate the diversity and pervasive nature of BBDG in extreme environments.

Biodiversity and biotechnological applications of halophilic microbes for sustainable agriculture

“…Among Bacillus and Bacillus-derived genera, Bacillus thuringiensis, Bacillus subtilis, Bacillus pumilus, Bacillus mycoides, Bacillus megaterium, and Bacillus firmus are ubiquitous in rhizosphere saline soil [1,27,28]. The genus Bacillus consists of a heterogenic group of endospores forming Gram-positive rods, which survive for extended periods under adverse environmental conditions due to endospores.…”

“…Halotolerant microbes specifically require salt for growth and development under the normal and saline conditions. The salt-loving microbes can be grouped as true halophiles (15-30% NaCl), moderate halophiles (3-15% M NaCl), and slight halophiles (1-2% NaCl) [1]. plant growth, and soil health for sustainable agriculture have been discussed.…”

Beneficial microbiomes: Biodiversity and potential biotechnological applications for sustainable agriculture and human health

“…Novel and efficient thermophilic microbes have been isolated and characterized from thermal extreme environments of world such as Thermotoga elfii [58], Thermotoga hypogeal [59], Thermoanaerobacter uzonensis [60], Bacillus thermophilus [61], and Herbinix luporum [62]. In the study by Yadav et al [39], 195 isolates from Indian hot water springs (Manikaran, Balarampur, Vashisht, Chumathang, and Bakreshwar) have been isolated and characterized for different beneficial attributes of hydrolytic enzymes production and PGP under normal as well as high-temperature conditions. The many nichespecific Bacillus and Bacillus and derived genera (BBDG) have been reported from thermal spring, for example, Bacillus fusiformis (B-10) from Bakreshwar and Brevibacillus from Vashisht and Balrampur [39].…”

“…In the study by Yadav et al [39], 195 isolates from Indian hot water springs (Manikaran, Balarampur, Vashisht, Chumathang, and Bakreshwar) have been isolated and characterized for different beneficial attributes of hydrolytic enzymes production and PGP under normal as well as high-temperature conditions. The many nichespecific Bacillus and Bacillus and derived genera (BBDG) have been reported from thermal spring, for example, Bacillus fusiformis (B-10) from Bakreshwar and Brevibacillus from Vashisht and Balrampur [39].…”

“…There are many reports on microbial diversity from extreme environments, for example, low temperature [9,[34][35][36], high temperature [3-6,37], saline soil [38], drought [39], acidic soil [39], and alkaline soil [11,39]. Microbe isolated and sort out from extreme environments may have exhibited PGP attributes, and thus, these abiotic stress tolerant microbes can be applied for plant growth under respective abiotic stress conditions.…”