Abstract

Extreme saline environments represent unique ecosystems for novel microbial biodiversity. The salt-tolerant microbiomes have been reported from diverse saline habitat. The biodiversity of salt-tolerant microbes showed the presence of different groups of microbes including Actinobacteria, Bacteroidetes, Euryarchaeota, Firmicutes, Proteobacteria, and Spirochaetes. The salt-tolerant plant growth promoting (PGP) microbes such as Ammoniphilus, Arthrobacter,Azospirillum, Bacillus, Brevibacillus, Brevibacterium, Haloarcula, Halobacillus, Halococcus, Haloferax, Halolamina, Halomonas, Halorubrum,Haloterrigena, Lysinibacillus, Marinobacter,Marinospirillum, Oceanobacillus, Paenibacillus, Penicillium, Pontibacillus, Pseudomonas, Sediminibacillus, Sporosarcina, Streptomyces, Thalassobacillus, and Thermonema have been isolated and characterized for plant growth under the salinity stress. The halophilic microbes have ability to produce phytohormones (indole acetic acids, gibberellic acids, and cytokinin), solubilize and bind nutrients(phosphorus, potassium, zinc, and siderophores), besides eliciting plant defense reactions against pathogens, also help in plant growth under harsh saline environments. The halophilic PGP microbes increase the plant growth, yields, and nutrient uptake under the saline condition. In the present review, the biodiversity of halophilic microbes from diverse ecosystems, its functional PGP attributes and mechanisms of action for amelioration of salt stress, plant growth, and soil health for sustainable agriculture have been discussed. The salt-tolerant microbes with multifarious PGP attributes could be applied for plant growth and ameliorations of salt stress.

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