Inoculation of methylotrophs mitigates heat and UV stress in mung bean (Vigna radiata L.) and enhances growth, antioxidant, and functional diversity.

Abstract

Climate change involves the induction of heat and solar ultraviolet (UV) radiation, which profoundly affects sustainable crop production. Increasing solar UV radiation negatively impacts the photosynthetic apparatus, plant-associated organisms, and plant health. The present study aimed to comprehensively assess methylotrophic bacteria to alleviate heat and UV radiation in Vigna radiata L. under pot studies and field conditions. Under normal and UVB stress conditions, inoculation of methylotrophs significantly enhanced seed germination (72.55%-96.70% (normal) and 51.67%-65.33% (stressed)) and improved plant growth parameters, total chlorophyll (25.80-48.16 mg/g (normal) and 9.13-27.88 mg/g (stressed)), and carotenoid (569.1-1067.1 μg/g (normal) and 287.8-903.4 μg/g (stressed)) contents. A similar enhancement in antioxidant properties such as superoxide dismutase (1-5 fold), peroxidase (1-9 fold), phenylalanine ammonia lyase (1-4 fold), and proline content (1-5 fold) was observed in response to UVB radiation and heat stress under pot studies. A community-level physiological profile (CLPP) study of leaf samples revealed enhanced AWCD in methylotrophs treated plants compared to the UVB-exposed controls. Furthermore, field studies in summer conditions confirmed that inoculation with methylotrophs had a positive effect on V. radiata growth and physiology. The methylotrophs inoculation increased pod formation (25.44-32.78 and 15.56-32.00) and yield (109.81-238.63 and 71.88-216.29 q/ha) under UV cut-off sheet covered and non-covered conditions, respectively. This study demonstrated the potential of methylotrophs to mitigate heat and solar (UV) radiation in plants and provide sustainable strategies for agriculture and the environment.