Does the heat tolerance induced by Sargassum horneri extract in Pyropia yezoensis sporophytes transfer to gametophytes?
摘要
Rising seawater temperatures pose a growing threat to the aquaculture of Pyropia yezoensis, a cold-water red seaweed widely cultivated in Korea, China and Japan. To address this challenge, this study investigated whether thermal resistance enhanced by treatment with Sargassum horneri extract (SHE) during the sporophyte stage is transmitted to the gametophyte stage. Sporophytes received treatments prepared by diluting a S. horneri extract (SHE) stock solution (10 g L⁻1, prepared from S. horneri powder on a dry weight basis) to final concentrations of 0, 0.001, 0.005, and 0.01 g L⁻1 in seawater, and were subsequently cultured into gametophytes, which were exposed to both normal (10℃) and elevated (20℃) temperatures. Physiological and biochemical analyses revealed that SHE-treated gametophytes exhibited enhanced growth, displayed reduced oxidative stress and increased antioxidant enzyme activity during heat stress. The optimal concentration (0.01 g L−1) maintained growth and stress response indicators at levels comparable to those observed under non-stress conditions. RNA sequencing further confirmed the upregulation of heat-responsive genes, including a SHE-specific small heat shock protein, suggesting potential epigenetic regulation. These findings demonstrate that SHE treatment during the sporophyte stage enhances thermal tolerance in the subsequent gametophyte generation. This cross-life-cycle effect presents a practical and sustainable strategy to improve heat resilience in P. yezoensis aquaculture under climate change.