TABLE 1.

Impact of PGPB in the enhancement of drought tolerance in crop plants.

Crop plants	PGPB involved	Impact on plant	References
Pepper	B. licheniformis K11	IAA and ACC deaminase produced by the PGPB helps in the mitigation of stress and also in the modulation of the genes and proteins involved in stress response such as sHSP Cadhn, and CaPR-10	Lim and Kim, 2013
Peach	B. cereus AR156 B. subtilis SM21	Production of ROS scavenging enzymes which often lead to a reduction in lipid peroxidation and boost the protection of plant membranes	Wang et al., 2013
Potato	B. pumilus strain DH-11	Enhancement of the efficiency of photosynthesis via an increment in ROS production	Gururani et al., 2013
Rice	P. synxantha R81 P. jessenii R62 A. nitroguajacolicus YB3 B. cereus BSB38	Activation of antioxidative defense system which results in the alleviation of oxidative stress in crop plants.	Gusain et al., 2015
Pea	Pseudomonas sp.	Alteration in the architecture of the root system and ACC deaminase production	Arshad et al., 2008
Sorghum	Bacillus sp. K142 and K122	Improvement of plant growth of crops exposed to stress. Such as increment in the content of relative water, shoot length, chlorophyll root dry biomass, and proline content	Grover et al., 2014
Wheat	B. amyloliquefaciens 5113	Bacterial priming in the plants reduced reactive oxygen species levels in drought-stressed plants.	Kasim et al., 2013
Rice	S. yanoikuyae	Enhancement of antioxidant enzymes, plant growth, and relative water content and in contrast to the control	Arunthavasu et al., 2019
Maize	B. thuringiensis HYDGRFB19 B. licheniformis HYTAPB18 P. favisporus BKB30 B amyloliquefaciens HYD-B17	Production of antioxidant enzymes and osmolytes	Daniel, 2019
Green gram	P. fluorescens strain Pf1 B. subtilis EPB5	Proline content accumulation and antioxidant enzymes for the enhancement of drought tolerance.	Saravanakumar et al., 2011
Sunflower	A. xylosoxidans SF2 B. pumilus SF3	Increment in phytohormones production	Castillo et al., 2013
Rice	B. altitudinis FD48	Proline content accumulation and increased plant biomass.	Narayanasamy et al., 2020
Black gram	Rhizobium sp. VRE1	Increased vigor index, germination efficiency, and production of exopolysaccharide.	Raja and Uthandi, 2019; Annadurai et al., 2020
Rice	B. megaterium	Alteration in the architecture of the root system for drought stress enhancement.	Vidhyasri et al., 2019
Potato	A. xylosoxidans Cm4, P. oryzihabitans Ep4, and V. paradoxus 5C-2	Modulation of phytohormone levels	Belimov et al., 2015
Black gam and Pea	O. pseudogrignonense RJ12, Pseudomonas sp. RJ15, B. subtilis RJ46	Elevated cellular osmolyte and ROS synthesis, higher leaf chlorophyll content, and increased relative water content	Saikia et al., 2018
Wheat and Maize	Bacillus sp. (12D6) and Enterobacter sp. (16i)	Increased indole-3-acetic acid (IAA) and salicylic acid (SA)	Jochum et al., 2019
Maize	B. velezensis D3	Increased vapor, pressure, photosynthesis rate, transpiration rate, stomatal conductance, and water-use efficiency.	Nadeem et al., 2021
Maize	B. licheniformis, B. amyloliquefaciens, and B. laterosporus	Alteration of plant metabolic pathways, including pathways, encoding redox homeostasis, strengthening of the plant cell wall, energy production, membrane remodeling, and osmoregulation.	Nephali et al., 2021
Wheat	S. maltophilia and A. brasilense NO40 B11	Proline content accumulation and the activities of peroxidase and catalase	Kasim et al., 2021
Maize	B. cereus (DS4) and B. albus (DS9)	Production of phytohormones and antioxidant enzymes for the enhancement of drought tolerance.	Ashry et al., 2022
Broad bean	R. leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279)	Increased antioxidant enzyme activities and osmoprotectants	Mansour et al., 2021