Response of the persistence of heat stress tolerance in winter wheat seedling to heat priming at early growth stages

Abstract

This study aimed to investigate the impact of heat priming on the heat stress tolerance of winter wheat seedlings. A hydroponic experiment was conducted with four treatments i.e. no priming and no heat stress (CK), no priming with heat stress (NP-HT), priming with no recovery prior to heat stress subjection (PNR-HT), and priming with heat recovery prior to heat stress subjection (PHR-HT). Biomass, chlorophyll index in flag leaves (SPAD), photosynthetic rate (Pn), stomatal conductance (Gs), protein profiling in young leaves using SDS-Page, and the expression level of heat-responsive and antioxidants responsive genes using RT-qPCR were measured to achieve the objective. The results showed that plants with no heat priming and subjected to heat stress had significantly reduced biomass, SPAD, Pn, Gs and protein content. In contrast, plants that received heat priming with or without recovery had better biomass, SPAD, Pn, Gs and protein content, showing the most significant improvement. The analysis of SDS-PAGE showed alterations in the protein patterns, specifically an upregulation of a 60 kDa protein, subsequent to exposure to heat stress. The study also found that heat priming triggered the up regulation of heat and antioxidants responsive genes. In conclusion, the study provides evidence that heat priming is an effective strategy for enhancing the heat stress tolerance of winter wheat and the primed plants that were allowed to recovery before heat stress exposure exhibited better stress tolerance than the primed plants that were immediately exposed to heat stress.