State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, China.
Tree Physiol. 2023 Aug 11;43(8):1432-1443. doi: 10.1093/treephys/tpad052.
Seasonal greening is a crucial survival strategy for albino tea cultivars, during which dysfunctional chloroplasts recover and chlorophyll biosynthesis increases in albino leaves. However, the regulatory mechanisms of seasonal greening in albino tea plants remain unclear. Here, we report that CsRVE1, a nuclear-located Myb-like transcription factor, can positively modulate the seasonal greening of albino Camellia sinensis cv. Huangkui leaves by activating the expression of genes involved in light harvesting and chlorophyll biosynthesis. The transcriptional expression of CsRVE1 increased during seasonal greening and was tightly correlated with increases in the expression of genes involved in light harvesting (CsLhcb) and chlorophyll biosynthesis (CsCHLH, CsHEMA1 and CsCAO). In vivo and in vitro molecular analyses showed that CsRVE1 can directly bind to the promoters of CsLhcb, CsCHLH and CsPORA, eventually leading to chlorophyll accumulation in tea leaves. Furthermore, transient suppression of CsRVE1 in tea leaves led to a decrease in target gene expression. In contrast, the overexpression of CsRVE1 in Arabidopsis led to chlorophyll increases and the activation of AtLhcb, AtPORA, AtCHLH, etc. These results identify CsRVE1 as an important promoter of seasonal greening that functions by regulating genes involved in chlorophyll biosynthesis in albino tea plants and shed new light on the regulatory mechanisms of leaf phenotypes in plants.
季节性返绿是白化茶树品种的关键生存策略，在此过程中，白化茶树的功能失调的叶绿体恢复，叶绿素生物合成增加。然而，白化茶树季节性返绿的调控机制仍不清楚。在这里，我们报道了 CsRVE1，一个定位于细胞核的 Myb 样转录因子，通过激活与光捕获和叶绿素生物合成相关的基因的表达，正向调控白化的黄魁茶树 cv. 叶片的季节性返绿。CsRVE1 的转录表达在季节性返绿过程中增加，与参与光捕获的基因（CsLhcb）和叶绿素生物合成的基因（CsCHLH、CsHEMA1 和 CsCAO）的表达增加紧密相关。体内和体外分子分析表明，CsRVE1 可以直接与 CsLhcb、CsCHLH 和 CsPORA 的启动子结合，最终导致茶树叶片中叶绿素的积累。此外，在茶树叶片中瞬时抑制 CsRVE1 会导致靶基因表达的减少。相比之下，在拟南芥中过表达 CsRVE1 会导致叶绿素增加和 AtLhcb、AtPORA、AtCHLH 等的激活。这些结果表明 CsRVE1 是白化茶树季节性返绿的一个重要启动子，通过调节与叶绿素生物合成相关的基因来发挥作用，并为植物叶片表型的调控机制提供了新的见解。
