Overview of the role of rhizobacteria in plant salt stress tolerance

20 páginas, 2 tablas, 2 figurasSalinity is one of the main causes of abiotic stress in plants, resulting in negative effects on crop growth and yield, especially in arid and semi-arid regions. The effects of salinity on plant growth mainly generate osmotic stress, ion toxicity, nutrient deficiency, and oxidative stress. Traditional approaches for the development of salt-tolerant crops are expensive and time-consuming, as well as not always being easy to implement. Thus, the use of plant growth-promoting bacteria (PGPB) has been reported as a sustainable and cost-effective alternative to enhance plant tolerance to salt stress. In this sense, this review aims to understand the mechanisms by which PGPB help plants to alleviate saline stress, including: (i) changes in the plant hormonal balance; (ii) release of extracellular compounds acting as chemical signals for the plant or enhancing soil conditions for plant development; (iii) regulation of the internal ionic content of the plant; or iv) aiding in the synthesis of osmoprotectant compounds (which reduce osmotic stress). The potential provided by PGPB is therefore an invaluable resource for improving plant tolerance to salinity, thereby facilitating an increase in global food production and unravelling prospects for sustainable agricultural productivityM.A.-C. is the recipient of a pre-doctoral fellowship from University of Salamanca; J.D.F.-F. is currently a recipient of post-doctoral Marie Skłodowska-Curie Fellowship No. 101003373. This work was supported by Grants PID2019-109960RB-100 from MCIN (Spanish Ministry of Science and Innovation) and Strategic Research Programs for Units of Excellence from Junta de Castilla y León (CLU-2O18-04)Peer reviewe