NO protect the wheat embryo from oxidative damage by triggering the biochemical defence network and amylolytic activity

Abstract

Nitric oxide has been reported to enhance the tolerance of plants to biotic and abiotic stresses. Wheat is highly affected by heat stress at different stages of growth and development. Tolerance to heat stress (HS) at germination stage is important for wheat crop in Central and Peninsular India. Here, we studied the effect of pre-treatment of seeds with NO (150 µmol) on the activity of enzymes associated with germination and overall tolerance of seedlings of contrasting wheat cvs. Raj3765 and HD2932 under differential HS. NO was observed to self-regulate it’s biosynthesis through upregulation of NOS and NR in seedlings under NO and HS treatments. HSP90, HSP70, SOD and CAT showed very high expression in response to NO and HS, as compared to control. An increase in the activities of α/β-amylases were observed in response to NO and HS in seedlings. The NO effect was more pronounced in the seedlings of thermotolerance cv. Raj3765, as compared to thermosusceptible cv. HD2932. We observed an increase in the activities of antioxidant enzymes (SOD, CAT and POX) in response to NO. Enhancement of biochemical traits associated with thermotolerance were also observed in seedlings treated with NO under HS. NO mitigated the effect of HS by triggering the SAGs and antioxidant enzymes associated defence network and thus tolerance of wheat seedling to HS. This provides an easy and cheap method to mitigate the effect of HS on germination in wheat.