Tea Research Institute, Zhejiang University, #866, Yuhangtang Road, Hangzhou 310058, China.
Int J Mol Sci. 2022 Jul 31;23(15):8522. doi: 10.3390/ijms23158522.
The light-sensitive (LS) albino tea plant grows albinic shoots lacking chlorophylls (Chls) under high-light (HL) conditions, and the albinic shoots re-green under low light (LL) conditions. The albinic shoots contain a high level of amino acids and are preferential materials for processing quality green tea. The young plants of the albino tea cultivars are difficult to be cultivated owing to lacking Chls. The mechanisms of the tea leaf bleaching and re-greening are unknown. We detected the activity and composition of photosystem II (PSII) subunits in LS albino tea cultivar "Huangjinya" (HJY), with a normal green-leaf cultivar "Jinxuan" (JX) as control so as to find the relationship of PSII impairment to the albino phenotype in tea. The PSII of HJY is more vulnerable to HL-stress than JX. HL-induced degradation of PSII subunits CP43, CP47, PsbP, PsbR. and light-harvest chlorophyll-protein complexes led to the exposure and degradation of D1 and D2, in which partial fragments of the degraded subunits were crosslinked to form larger aggregates. Two copies of subunits PsbO, psbN, and Lhcb1 were expressed in response to HL stress. The cDNA sequencing of CP43 shows that there is no difference in sequences of PsbC cDNA and putative amino acids of CP43 between HJY and JX. The de novo synthesis and/or repair of PSII subunits is considered to be involved in the impairment of PSII complexes, and the latter played a predominant role in the albino phenotype in the LS albino tea plant.
感光性（LS）白化茶树在强光（HL）条件下长出缺乏叶绿素（Chls）的白化芽，在低光（LL）条件下白化芽重新变绿。白化芽含有高水平的氨基酸，是加工优质绿茶的首选材料。由于缺乏 Chls，白化茶品种的幼苗难以培育。茶叶白化和返绿的机制尚不清楚。我们检测了 LS 白化茶树品种“黄芽金骏眉”（HJY）和正常绿叶茶树品种“金萱”（JX）中 PSII 亚基的活性和组成，以期发现 PSII 损伤与茶树白化表型的关系。HJY 的 PSII 比 JX 更容易受到 HL 胁迫的影响。HL 诱导 CP43、CP47、PsbP、PsbR 和光捕获叶绿素蛋白复合物的 PSII 亚基降解，导致 D1 和 D2 的暴露和降解，其中降解亚基的部分片段交联形成更大的聚集体。两个拷贝的亚基 PsbO、psbN 和 Lhcb1 被表达以响应 HL 应激。CP43 的 cDNA 测序表明，HJY 和 JX 之间的 PsbC cDNA 序列和 CP43 的推定氨基酸没有差异。PSII 亚基的从头合成和/或修复被认为参与了 PSII 复合物的损伤，而后者在 LS 白化茶树的白化表型中起主导作用。
