Ameliorative symbiosis of Serratia fonticola (S1T1) under salt stress condition enhance growth-promoting attributes of Cucumis sativus L

초록

Salinity stress is a combination of ionic, osmotic, and oxidative stressors that have a negative impact on crop growth and production. In the present study, experiments were conducted to investigate the role of multi-traits Serratia fonticola (S1T1) on Cucumis sativus L. growing under salinity stress (200 mM). The control plants had stunted growth, while S. fonticola (S1T1) root zone treated plants revealed significantly higher fresh (26.71%) and dry (24.8%) biomass, and improved level of chlorophyll content (25.24%) followed by foliar application of S. fonticola (S1T1) under salt stress. Similarly, increased water potential (15-20%), decreased (14-20%) endogenous abscisic acid (ABA) and lower electrolytic leakage (21-35%) were additional proof of the beneficial impacts of root zone inoculated C. sativus L. under salt stress conditions. Antioxidant analysis revealed a decrease in malondialdehyde (MDA) content (13-31%), H2O2 content (15-36%) and superoxide anion (SOA) (11-32%) while an increase in antioxidant enzymes such as catalase (CAT) (13.2-35.5%) and superoxide dismutase (SOD) (9.61-29.7%). The root zone and foliar application of S. fonticola (S1T1) on cucumber plants improved salt-stress tolerance by up-regulating the transcript accumulation of ion transporter genes HKT1 (2-3-folds), NHX (18.2-folds) and SOS1 (8.2-folds). Conclusively, the symbiotic association of S. fonticola (S1T1) can alleviate the antagonistic effects of salinity stress, improve cucumber plant growth and could be utilized as an eco-friendly biofertilizer or microbial plant biostimulant (MBPs) under salt stress conditions.

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