ABSTRACT
The extreme cold environments harbor novel psychrotrophic microbes. The psychrotrophic microbes have been reportedas plant growth promoters and biocontrol agents for sustainable agriculture, in industry as cold-adapted hydrolyticenzymes and in medicine as secondary metabolites and pharmaceutical important bioactive compounds. Inoculationwith psychrotrophic/psychrotolerant strains significantly enhanced root/shoot biomass and nutrients uptake as comparedto non-bacterized control. The psychrotrophic microbes play important role in alleviation of cold stress in plant growingat high hill and low temperature and conditions. The psychrotrophic microbes have been reported from worldwidefrom cold habitats and belong to all three domain archaea, bacteria, and eukarya including different phylum such asActinobacteria, Ascomycota, Bacteroidetes, Basidiomycota, Chloroflexi, Chlamydiae, Planctomycetes, Cyanobacteria,Euryarchaeota, Firmicutes, Gemmatimonadetes, Verrucomicrobia, Mucoromycota, Proteobacteria, Spirochaetes,Thaumarchaeota and Nitrospirae. The most dominant genera belong to Arthrobacter, Bacillus, Exiguobacterium,Paenibacillus, Providencia, Pseudomonas, and Serratia have been reported from the cold habitats. The Psychrotrophicmicrobes have biotechnological applications in agriculture, medicine, industry, food, and allied sectors
ABSTRACT
The plant growth promoting psychrotrophic Bacilli were investigated from different sites in north western Indian Himalayas. A total of 247 morphotypes were obtained from different soil and water samples and were grouped into 43 clusters based on 16S rDNA-RFLP analysis with three restriction endonucleases. Sequencing of representative isolates has revealed that these 43 Bacilli belonged to different species of 11 genera viz., Desemzia, Exiguobacterium, Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus, Pontibacillus, Sinobaca, Sporosarcina, Staphylococcus and Virgibacillus. With an aim to develop microbial inoculants that can perform efficiently at low temperatures, all representative isolates were screened for different plant growth promoting traits at low temperatures (5-15°C). Among the strains, variations were observed for production (%) of indole-3-acetic acid (20), ammonia (19), siderophores (11), gibberellic acid (4) and hydrogen cyanide (2); solubilisation (%) of zinc (14), phosphate (13) and potassium (7); 1-aminocyclopropane-1-carboxylate deaminase activity (6%) and biocontrol activity (4%) against Rhizoctonia solani and Macrophomina phaseolina. Among all the strains, Bacillus licheniformis, Bacillus muralis, Desemzia incerta, Paenibacillus tylopili and Sporosarcina globispora were found to be potent candidates to be developed as inoculants as they exhibited multiple PGP traits at low temperature.