Biochemical Insights into Lipid Remodeling in Wheat Anthers Under High-Temperature Stress

High-temperature (HT) stress during flowering significantly impairs anther development and pollen fertility, leading to substantial yield loss in wheat. A key aspect of plant adaptation to temperature stress concerns remodeling of lipid metabolism. In this study, heat-tolerant and heat-sensitive wheat cultivars were employed to investigate the biochemical alterations in lipid metabolism in response to high-temperature (HT) stress during anthesis. Pollen viability and SEM demonstrated that, under high temperature, the heat-tolerant cultivar maintained a more stable pollen structure and exhibited higher pollen fertility compared to the sensitive cultivar. Fatty acid analysis showed that HT led to a decrease in the unsaturated fatty acid 18:3 and an increase in the saturated fatty acid 16:0, thereby reducing the double bond index in both cultivars. Lipidomic profiling revealed that HT caused a shift toward higher levels of saturated acyl chains, reducing unsaturation in both phospholipids and galactolipids. Notably, the levels of saturated lipids such as PC (34:0) and PA (36:0) increased markedly upon heat exposure in the heat-tolerant cultivar, whereas only minor changes were observed in the heat-sensitive cultivar. Furthermore, analysis of cuticular lipids showed a reduction in polyunsaturated cutin components under high temperature in wheat anthers. Heat treatment caused a substantial reduction in fertile spikelet rate in both cultivars, while the heat-tolerant cultivar maintained a better seed setting and higher yield. These findings provide biochemical insights into lipid metabolic adjustments that underlie thermotolerance during anthesis in wheat.