Plant Growth-Promoting Rhizobacteria Ameliorates Salinity Stress in Pea (Pisum sativum)

Pea is an important legume vegetable crop which is an essential component of human nutrition. Salinity impedes plant growth and productivity of legume crops by disrupting the ionic and osmotic balance and hormonal regulation. The present study was aimed to examine the potential of plant growth-promoting rhizobacteria (PGPR) strains IG 2 (Acinetobacter bereziniae), IG 10 (Enterobacter ludwigii), and IG 27 (Alcaligenes faecalis) in mitigating salinity stress (75 mM and 150 mM NaCl) in pea. Overall the PGPR inoculation (IG 2, IG 10, and IG 27) improved the growth parameters of pea seedling under salinity stress, but PGPR strain IG 27 had better performance than the other two PGPR strains, i.e., IG 10 and IG 2. Similarly, PGPR inoculation modulated the biochemical parameters such as chlorophyll content, proline content, total soluble sugar, electrolyte leakage, and activities of antioxidant enzymes for alleviation of salt stress. Moreover, PGPR-inoculated plants demonstrated lower levels of electrolyte leakage and H2O2 content under saline conditions in relation to un-inoculated pea seedlings. Additionally, PGPR inoculation of pea plant in field trials with 100 mM NaCl stress exhibited enhanced plant growth and yield. Taken together, our findings suggest the beneficial role of PGPR in alleviating the detrimental effect of salinity on pea seedling growth and yield, further could be used as bio-inoculants to improve crop productivity in saline environment.