Enhancing Zea mays L. seedling growth with He[sbnd]Ne laser-irradiated Alcaligenes sp. E1 to mitigate salinity stress.

• Plant growth-promoting rhizobacteria (PGPR) are a considerable and favourable strategy to improve agriculture and mitigate abiotic stress. • To increase the efficacy of this approach, the utilization of He Ne laser radiation (L) and methylene blue (MB) as photosensitizer are commonly suggested to increase the efficiency of IAA-producing rhizobacterial strain Alcaligenes sp. E1 on maize growth under salt stress. • The use of treated PGPR under salt stress induced an increase in shoot length (44 %), root length (49 %), fresh weight (34 %), dry weight (45.6 %), chlorophyll a (51 %), and carotenoids (71 %) over the stressed control. • The results showed that irradiation of the tested bacterium by a 10 mW He Ne laser significantly increase IAA production compared to non-irradiated and photosensitized bacteria. • Irradiation of bacterial suspension increases the efficacy of bacteria to synthesize IAA. Plant growth-promoting rhizobacteria (PGPR) are a beneficial strategy to improve agriculture and mitigate abiotic stress. To increase the efficacy of this approach, the utilization of He Ne laser radiation (L) and methylene blue (MB) as photosensitizer is commonly suggested. This study evaluated the role of the IAA-producing rhizobacterial strain Alcaligenes sp. E1 on maize growth under salt stress (150 mM NaCl) with the application of laser and methylene blue. The results showed that treatment of Alcaligenes sp. E1 with red laser and methylene blue exhibited a maximum increase in shoot length (44 %), root length (49 %), fresh weight (34 %), dry weight (45.6 %), chlorophyll a (51 %), and carotenoids (71 %) over the stressed control. In addition, it demonstrated more activity to antioxidant activities (SOD, CAT, GSH, and TAC) and limited oxidative damage resulting from ROS formation. In conclusion, Alcaligenes sp. has a good ability to stimulate maize growth when applied with laser radiation and photosensitizer under normal and saline conditions. Thus, we propose that red laser and photosensitizer will have promising applications in crop biostimulation and sustainable agriculture. [ABSTRACT FROM AUTHOR]