Table_13_Multi-Approach Analysis Reveals Pathways of Cold Tolerance Divergence in Camellia japonica.XLSX

Understanding the molecular mechanism of the cold response is critical to improve horticultural plant cold tolerance. Here, we documented the physiological, transcriptome, proteome, and hormonal dynamics to cold stress in temperate genotype (Tg) and subtropical genotype (Sg) populations of Camellia japonica. Tg C. japonica suffered minimal osmotic and oxidative damage compared to Sg C. japonica under the same cold treatment. Transcriptional and translational differences increased under the cold treatment, indicating that Tg C. japonica was affected by the environment and displayed both conserved and divergent mechanisms. About 60% of the genes responding to cold had similar dynamics in the two populations, but 1,896 transcripts and 455 proteins differentially accumulated in response to the cold between Tg and Sg C. japonica. Co-expression analysis showed that the ribosomal protein and genes related to photosynthesis were upregulated in Tg C. japonica, and tryptophan, phenylpropanoid, and flavonoid metabolism were regulated differently between the two populations under cold stress. The divergence of these genes reflected a difference in cold responsiveness. In addition, the decrease in the abscisic acid (ABA)/gibberellic acid (GA) ratio regulated by biosynthetic signal transduction pathway enhanced cold resistance in Tg C. japonica, suggesting that hormones may regulate the difference in cold responsiveness. These results provide a new understanding of the molecular mechanism of cold stress and will improve cold tolerance in horticultural plants.解析植物冷应答的分子机制，对于提升园艺作物的耐寒性至关重要。本研究以温带基因型（Tg）和亚热带基因型（Sg）的山茶（Camellia japonica）群体为材料，系统记录了其在冷胁迫下的生理、转录组（transcriptome）、蛋白组（proteome）及激素动态变化特征。在相同冷胁迫处理下，温带基因型山茶相较于亚热带基因型山茶，仅遭受极轻微的渗透胁迫与氧化损伤。冷胁迫处理下，转录与翻译水平的差异程度均有所升高，表明温带基因型山茶受到环境胁迫的影响，且其冷应答机制兼具保守性与分化性。约60%的冷应答基因在两个群体中呈现相似的表达动态，但温带与亚热带基因型山茶间，共有1896个转录本及455个蛋白在冷胁迫下的积累量存在显著差异。共表达分析结果显示，温带基因型山茶中核糖体蛋白（ribosomal protein）及光合相关基因均呈上调表达；而冷胁迫下，两个群体在色氨酸、苯丙烷类（phenylpropanoid）及黄酮类（flavonoid）物质代谢的调控模式上存在显著差异。这些基因的表达分化，直接反映了二者冷应答能力的差异。此外，由生物合成信号转导通路调控的脱落酸（abscisic acid, ABA）/赤霉素（gibberellic acid, GA）比值降低，提升了温带基因型山茶的耐寒性，这表明激素或许参与调控了二者冷应答能力的差异。本研究结果为解析冷胁迫的分子机制提供了新视角，同时可为提升园艺作物的耐寒性提供理论依据。