Table 2.
PGPB-produced mechanisms related to tolerance against salinity stress.
| PGPB | Plants | Effects | Mode of Action | References |
|---|---|---|---|---|
| P. mendocina | Lactuca sativa L. | Stable soil aggregates in high proportions | ESP production | [259] |
| A. brasilense and Pantoea dispersa | Capsicum annuum L. | Increased dry weight and K+/Na+ ratio | Maintaining of higher stomatal conductance | [276] |
| B. aquimaris | T. aestivum L. | Increased weight, biomass, and leaf nutrients |
Accumulation of osmoprotectants (TSS and proline) | [264] |
| Rhizobium sp. and Pseudomonas sp. | Zea mays L. | Increased plant biomass, development, and nutrient uptake | Accumulation of osmoprotectants (proline, Betaine), water and ion homeostasis | [58] |
| Pseudomonas sp. | S. lycopersicum L. | Higher shoot and root length, total dry weight, and chlorophyll content | ACCD production and osmoprotectants accumulation (trehalose) | [272] |
| B. megaterium | Z. mays L. | Higher root hydraulic conductance | Up-regulation of aquoporin genes (PIPtype) | [274] |
| B. subtilis |
Puccinellia tenuiflora SCRIBN. & MERR. |
Improved shoot and root growth and decreased Na+ ion accumulation | Ion transport genes (HKT type): transcriptional changes | [277] |
| P. simiae | G. max L. | Higher weight, length, and K+/Na+ ratio | Changes in transcriptional regulation of phosphatase activity, proline accumulation, and the production of VOCs | [278] |
| Rhizobium sp. and Pseudomonas sp. | Z. mays L. | Enhanced plant biomass, nutrient uptake and development | Accumulation of proline, water and ion homeostasis | [58] |
| Pseudomonas sp. and Bacillus sp. | G. max L. | Increased water content, plant biomass, and photosynthetic activity | Production of IAA ESP, and ACCD and accumulation of proline | [279] |
| B. aquimaris | T. aestivum L. | Increased weight, biomass, and leaf nutrients |
Accumulation of osmoprotectans (PRP and TSS) | [264] |
| A. lipoferum | T. aestivum L. | Enhanced plant weight and chlorophyll content | N2 fixation and IAA production | [280] |
| Bacillus sp. | P. sativum L. | Enhanced morphological and biochemical parameters | IAA production, P-solubilization, ACCD, and hydrogen cyanide production | [41] |
| Bacillus and Pseudomonas sp. | P. sativum L. | Enhanced morphological and biochemical parameters and modulated antioxidant genes | ACCD production | [40] |
| A. piechaudii | S. lycopersicum L. | Increased dry and fresh weight, and K and P uptake | ACCD production | [171] |
| Burkholdera cepacian, Promicromonospora sp. and A. calcoaceticus | C. sativus L. | Enhanced biomass, photosynthetic pigments, water, and P and K content | Downregulation of ABA genes | [205] |
| Kocuria rhizophila | Z. mays L. | Reduction of Na+ accumulation and increase in productivity parameters | Transcriptional changes in ion transporter genes (NHX and HKT-type) and hormonal changes (ABA and IAA) | [281] |
| B. amyloliquefaciens | Menthax piperita L. | Improved morphological characteristics and higher chlorophyll content | VOCs production and reduction of ABA endogenous levels | [282] |
| Bradyrhizobium japonicum and B. thuringiensis | G. max L. | Germination of seeds and proteome changes | Lipo-chitooligosaccharide and bacteriocin production | [218] |
ESP—Exopolysaccharide; VOCs—Volatile Organic Compounds; ACCD—1-aminocyclopropane-1-carboxylate deaminase; ABA—Abscisic acid; IAA—Indole acetic acid; PRP—Proline-rich protein; TSS—Total soluble sugar; P—Phosphorus; N2—Nitrogen; NHX—vacuolar Na+/H+ antiporter; HKT—Sodium transporter.