Cold stress declines the quality and yield of tea, yet the molecular basis underlying cold tolerance of tea plants (Camellia sinensis) remains largely unknown. Here, we identified a circadian rhythm component LUX ARRHYTHMO (LUX) that potentially regulates cold tolerance of tea plants through a genome-wide association study and transcriptomic analysis. The expression of CsLUX phased with sunrise and sunset and was strongly induced by cold stress. Genetic assays indicated that CsLUX is a positive regulator of freezing tolerance in tea plants. CsLUX was directly activated by CsCBF1 and repressed the expression level of CsLOX2, which regulates the cold tolerance of tea plants through dynamically modulating jasmonic acid content. Furthermore, we showed that the CsLUX-CsJAZ1 complex attenuated the physical interaction of CsJAZ1 with CsICE1, liberating CsICE1 with transcriptional activities to withstand cold stress. Notably, a single-nucleotide variation of C-to-A in the coding region of CsLUX was functionally validated as the potential elite haplotype for cold response, which provided valuable molecular markers for future cold resistance breeding in tea plants.

中文翻译：

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LUX ARRHYTHMO 连接CBF途径和茉莉酸代谢调节茶树的耐寒性


冷胁迫会降低茶叶的品质和产量，但茶树（Camellia sinensis）耐冷性的分子基础仍然很大程度上未知。在这里，我们通过全基因组关联研究和转录组分析，确定了一种昼夜节律成分 LUX ARRHYTHMO (LUX)，它可能调节茶树的耐寒性。 CsLUX 的表达随日出和日落而定相，并受到冷应激的强烈诱导。遗传分析表明，CsLUX 是茶树耐冻性的正调节剂。 CsLUX直接被CsCBF1激活并抑制CsLOX2的表达水平，CsLOX2通过动态调节茉莉酸含量来调节茶树的耐寒性。此外，我们发现CsLUX-CsJAZ1复合物减弱了CsJAZ1与CsICE1的物理相互作用，释放具有转录活性的CsICE1以抵御冷应激。值得注意的是，CsLUX编码区的C到A的单核苷酸变异被功能验证为潜在的冷反应精英单倍型，这为未来茶树的抗冷育种提供了有价值的分子标记。