Genotypic-dependent alternation in D1 protein turnover and PSII repair cycle in psf mutant rice (Oryza sativa L.), as well as its relation to light-induced leaf senescence
Genotypic-dependent alternation in D1 protein turnover and PSII repair cycle in psf mutant rice (Oryza sativa L.), as well as its relation to light-induced leaf senescence
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DOI：
10.1007/s10725-021-00730-8
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发表时间：
2021-06
影响因子：
4.2
通讯作者：
Fubiao Wang;Huimin Sun;Ling-jie Rong;Zhaowei Li;T. An;Wenhai Hu;Z. Ye
中科院分区：
文献类型：
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作者：
Fubiao Wang;Huimin Sun;Ling-jie Rong;Zhaowei Li;T. An;Wenhai Hu;Z. Ye
为了阐明水稻衰老叶片中D1蛋白周转和PS Ⅱ修复周期的基因型依赖性变化及其与光强的关系，以psf突变体和野生型两种水稻基因型为材料，测定了它们的净光合速率（Pn）、PS Ⅱ叶绿素荧光参数、以及参与叶片衰老过程中D1蛋白周转的基因的转录水平。结果表明，与野生型相比，psf突变体的净光合速率、光能传递效率（Fv/Fm）和基于吸收的性能指数（PIabs）均降低。此外，我们的研究结果表明，psf突变体叶片衰老症状的出现主要取决于田间光照强度，而不是光质。psf突变体对缺糖胁迫和氧化损伤的保护作用是其延缓叶片衰老的重要机制。psf突变体叶片中的非磷酸化和磷酸化D1蛋白均随叶片衰老而减少，而非磷酸化D1蛋白的减少幅度更大。光诱导叶片衰老的开始和随后的进程与psf突变体叶片中D1蛋白的周转密切相关。完整叶片内的部分遮光处理伴随着减轻甚至修复遮光区的叶片早衰症状，这也抑制了D1蛋白的降解。在叶片衰老过程中，参与D1蛋白从头合成和PSII修复周期的关键基因OsPsbA和OsFtsHs的表达量较低。OsFtsH 2基因在不同的OsFtsH 1亚型中转录水平最高，也是受光照影响最大的亚型。而OsFtsH 5和OsFtsH 7仅在高光强条件下表达下调。因此，OsPsbA和OsFtsH 2对D1从头合成和光损伤D1降解的抑制作用主要是由于OsPsbA和OsFtsH 2的下调。OsFtsHisoforms可能在光诱导叶片衰老过程中对D1蛋白周转和PSII修复周期起协同或互补作用。
To clarify the genotypic-dependent alternation in D1 protein turnover and PSII repair cycle and its relation to light intensity in senescent leaves of rice, two rice genotypes, namely, thepsfmutant and its wild type, were used to determine their temporal differences in terms of the net photosynthetic rate (Pn), chlorophyll fluorescence parameters of PSII, and transcriptional levels of genes that participated in D1 protein turnover during leaf senescence. The results showed that compared to its wild type, thepsfmutant had lowerPn, solar energy transmitting efficiency (Fv/Fm), and performance index on absorption basis (PIabs) than its wild type. Moreover, our results showed that the emergence of leaf senescent symptoms forpsfmutant mainly depends on light intensity, instead of light quality in the field. The prevention of leaves from sugar starvation and oxidative damage contributes to the regulation of shaded-delayed leaf senescence in thepsfmutant. Both non-phosphorylated and phosphorylated D1 proteins in leaves of thepsfmutant were found decreasing with leaf senescence, while the non-phosphorylated one had more decrease. The initiation and subsequent progresses of leaf senescence induced by light were closely related to the D1 protein turnover in the leaves of thepsfmutant. Partial shading treatment within an intact leaf concomitantly alleviated or even repaired the leaf premature senescent symptoms of the shaded area, which also suppressed D1 protein from being degraded. The key genes (OsPsbAandOsFtsHs) participated in D1 protein de novo synthesis and PSII repair cycle had lower expression during leaf senescence. Among differentOsFtsHisoforms,OsFtsH2exhibited the highest transcriptional levels, and it was also the isoform gene with the largest decline in the light treatment. Meanwhile,OsFtsH5andOsFtsH7were only down-regulated in conditions with high light intensity. Therefore, the inhabitation of D1 de novo synthesis and photo-damaged D1 degradation are mainly due to the down-regulation ofOsPsbAandOsFtsH2. OtherOsFtsHisoforms may play synergistic or complementary roles in D1 protein turnover and PSII repair cycle in light-induced leaf senescence.