Sun Jia, Liang Weifang, Ye Shenghai, Chen Xinyu, Zhou Yuhang, Lu Jianfei, Shen Ying, Wang Xuming, Zhou Jie, Yu Chulang, Yan Chengqi, Zheng Bingsong, Chen Jianping, Yang Yong
College of Life Science, Fujian A&F University, Fuzhou, China.
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology for Plant Protection, Ministry of Agriculture, and Rural Affairs, Zhejiang Provincial Key Laboratory of Biotechnology for Plant Protection, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou, China.
Front Plant Sci. 2022 Jun 3;13:899054. doi: 10.3389/fpls.2022.899054. eCollection 2022.
Senescence is a necessary stage of plant growth and development, and the early senescence of rice will lead to yield reduction and quality decline. However, the mechanisms of rice senescence remain obscure. In this study, we characterized an early-senescence rice mutant, designated (), which was derived from the japonica rice cultivar Zhejing22. The mutant exhibited obvious early-senescence phenotype, such as collapsed chloroplast, lesions in leaves, declined fertility, plant dwarf, and decreased agronomic traits. The gene was mapped in a 458 kb-interval between the molecular markers RM5992 and RM5813 on Chromosome 3, and analysis suggested that is a novel gene controlling rice early senescence. Subsequently, whole-transcriptome RNA sequencing was performed on and its wild-type rice to dissect the underlying molecular mechanism for early senescence. Totally, 10,085 differentially expressed mRNAs (DEmRNAs), 1,253 differentially expressed lncRNAs (DElncRNAs), and 614 differentially expressed miRNAs (DEmiRNAs) were identified, respectively, in different comparison groups. Based on the weighted gene co-expression network analysis (WGCNA), the co-expression turquoise module was found to be the key for the occurrence of rice early senescence. Furthermore, analysis on the competing endogenous RNA (CeRNA) network revealed that 14 lncRNAs possibly regulated 16 co-expressed mRNAs through 8 miRNAs, and enrichment analysis showed that most of the DEmRNAs and the targets of DElncRNAs and DEmiRNAs were involved in reactive oxygen species (ROS)-triggered autophagy-related pathways. Further analysis showed that, in , ROS-related enzyme activities were markedly changed, ROS were largely accumulated, autophagosomes were obviously observed, cell death was significantly detected, and lesions were notably appeared in leaves. Totally, combining our results here and the remaining research, we infer that ROS-triggered autophagy induces the programmed cell death (PCD) and its coupled early senescence in mutant rice.
衰老 是植物生长发育的一个必要阶段，水稻的早衰会导致产量降低和品质下降。然而，水稻衰老的机制仍不清楚。在本研究中，我们鉴定了一个早衰水稻突变体，命名为（），它源自粳稻品种浙粳22。该突变体表现出明显的早衰表型，如叶绿体解体、叶片出现病斑、育性下降、植株矮化以及农艺性状降低。该基因被定位在第3染色体上分子标记RM5992和RM5813之间458 kb的区间内，分析表明它是一个控制水稻早衰的新基因。随后，对该突变体及其野生型水稻进行了全转录组RNA测序，以剖析早衰潜在的分子机制。在不同比较组中，分别鉴定出10,085个差异表达的mRNA（DEmRNA）、1,253个差异表达的lncRNA（DElncRNA）和614个差异表达的miRNA（DEmiRNA）。基于加权基因共表达网络分析（WGCNA），发现共表达的绿松石模块是水稻早衰发生的关键。此外，对竞争性内源RNA（CeRNA）网络的分析表明，14个lncRNA可能通过8个miRNA调控16个共表达的mRNA，富集分析表明，大多数DEmRNA以及DElncRNA和DEmiRNA的靶标都参与了活性氧（ROS）触发的自噬相关途径。进一步分析表明，在该突变体中，与ROS相关的酶活性显著改变，ROS大量积累，明显观察到自噬体，显著检测到细胞死亡，叶片中明显出现病斑。总的来说，结合我们这里的结果和其余研究，我们推断ROS触发的自噬诱导了突变体水稻中的程序性细胞死亡（PCD）及其相关的早衰。
