Expression of gibberellin synthesis genes and antioxidant capacity in common bean (Phaseolus vulgaris L. cv. Sadri) seeds induced by chitosan under salinity

Effects of chitosan on the expression of gibberellin synthesis genes, activity of antioxidant enzymes, and biochemical traits of common beans under salinity stress were analyzed using a factorial experiment based on a completely randomized design with four replications. four salinity levels (0, 50, 100 and 150 mm) and four chitosan levels (0, 0.25, 0.50, and 0.75% by weight-volume) were applied. expression of gibberellin synthesis genes (ga3ox1, ga3ox2, ga3ox3, ga3ox4, ga3ox5, and ga3ox6) was assessed using qrt-pcr along with some biochemical indices. salinity stress increased the activity of peroxidase and malondialdehyde (mda) content. chitosan 0.75% pretreatment increased peroxidase activity while decreasing mda content. phosphate content in seeds pretreated with 0.75% chitosan and no salinity increased by 57% compared to the control. with increasing salinity, the activity of superoxide dismutase, ascorbate peroxidase, and glutathione reductase increased while catalase activity decreased. increases by 14%, 46%, and 34% were observed in the activity of superoxide dismutase (in 0.25% chitosan pretreatment), and ascorbate peroxidase and glutathione reductase (in 0.75% chitosan pretreatment), respectively under 150 mm salinity stress. under no salinity, the activity of catalase enzyme increased by 39% in 0.75% chitosan pretreatment compared to the control. ga3ox1 gene expression in 0.75% chitosan priming under no salinity was higher than the other genes. with increasing salinity, gene expression decreased so that the lowest gene expression was non-primed seeds under 150 mm salinity. however, with further increase of salinity, expression of ga3ox4, ga3ox5, and ga3ox6 genes reached zero. the study suggests that seed priming with 0.75% chitosan can reduce the adverse effects of salinity and improve seedling growth in common bean, as chitosan enhances ga3ox genes under salinity, which are necessary for germination and seedling establishment.