College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Int J Mol Sci. 2019 Mar 4;20(5):1098. doi: 10.3390/ijms20051098.
Early leaf senescence is an important agronomic trait that affects crop yield and quality. To understand the molecular mechanism of early leaf senescence, () mutant rice with a deletion of and its wild type were employed in this study. The genotype-dependent differences in photosynthetic indexes, senescence-related physiological parameters, and yield characters were investigated during the grain-filling stage. Moreover, RNA sequencing (RNA-seq) was performed to determine the genotype differences in transcriptome during the grain-filling stage. Results showed that the mutant underwent significant decreases in the maximal quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), net photosynthesis rate (), and soluble sugar and protein, followed by the decreases in transcript and vacuolar H⁺-ATPase activity. Finally, yield traits were severely suppressed in the mutant. RNA-seq results showed that 4827 differentially expressed genes (DEGs) were identified in mutant between 0 day and 14 days, and the pathways of biosynthesis of secondary metabolites, carbon fixation in photosynthetic organisms, and photosynthesis were downregulated in the senescing leaves of mutant during the grain-filling stage. In addition, 81 differentially expressed TFs were identified to be involved in leaf senescence. Eleven DEGs related to hormone signaling pathways were significantly enriched in auxin, cytokinins, brassinosteroids, and abscisic acid pathways, indicating that hormone signaling pathways participated in leaf senescence. Some antioxidative and carbohydrate metabolism-related genes were detected to be differentially expressed in the senescing leaves of mutant, suggesting that these genes probably play response and regulatory roles in leaf senescence.
早期叶片衰老（leaf senescence）是影响作物产量和品质的一个重要农艺性状。为了理解早期叶片衰老的分子机制，本研究利用一个缺失 和其野生型（）的突变型水稻进行研究。在灌浆期，研究了基因型依赖的光合指标、衰老相关生理参数和产量性状的差异。此外，还进行了 RNA 测序（RNA-seq）以确定灌浆期转录组的基因型差异。结果表明，突变体的光合系统 II（PSII）光化学最大量子产量（Fv/Fm）、净光合速率（）和可溶性糖、蛋白质显著降低，随后 转录本和液泡 H⁺-ATP 酶活性降低。最终，突变体的产量性状受到严重抑制。RNA-seq 结果显示，在 0 天到 14 天之间，突变体与野生型之间有 4827 个差异表达基因（DEGs），在灌浆期衰老叶片中，生物合成次生代谢物、光合生物碳固定和光合作用的途径下调。此外，鉴定到 81 个参与叶片衰老的差异表达转录因子（TFs）。与激素信号通路相关的 11 个 DEGs 在生长素、细胞分裂素、油菜素内酯和脱落酸途径中显著富集，表明激素信号通路参与了叶片衰老。在突变体衰老叶片中检测到一些与抗氧化和碳水化合物代谢相关的基因差异表达，表明这些基因可能在叶片衰老中发挥响应和调节作用。
