PDF(Pubmed)
Abstract：
Premature leaf senescence significantly reduces rice yields. Despite identifying numerous factors influencing these processes, the intricate genetic regulatory networks governing leaf senescence demand further exploration. We report the characterization of a stably inherited, ethyl methanesulfonate(EMS)-induced rice mutant with wilted leaf tips from seedling till harvesting, designated lts2. This mutant exhibits dwarfism and early senescence at the leaf tips and margins from the seedling stage when compared to the wild type. Furthermore, lts2 displays a substantial decline in both photosynthetic activity and chlorophyll content. Transmission electron microscopy revealed the presence of numerous osmiophilic granules in chloroplast cells near the senescent leaf tips, indicative of advanced cellular senescence. There was also a significant accumulation of H2O2, alongside the up-regulation of senescence-associated genes within the leaf tissues. Genetic mapping situated lts2 between SSR markers Q1 and L12, covering a physical distance of approximately 212 kb in chr.1. No similar genes controlling a premature senescence leaf phenotype have been identified in the region, and subsequent DNA and bulk segregant analysis (BSA) sequencing analyses only identified a single nucleotide substitution (C-T) in the exon of LOC_Os01g35860. These findings position the lts2 mutant as a valuable genetic model for elucidating chlorophyll metabolism and for further functional analysis of the gene in rice.
摘要：
早叶衰老显著降低水稻产量。尽管确定了许多影响这些过程的因素，控制叶片衰老的复杂遗传调控网络需要进一步探索。我们报道了一个稳定遗传的表征，甲磺酸乙酯（EMS）诱导的水稻突变体，从幼苗到收获，叶尖枯萎，指定lts2。与野生型相比，该突变体在苗期的叶尖和边缘表现出矮化和早期衰老。此外，lts2的光合活性和叶绿素含量均大幅下降。透射电子显微镜显示在衰老叶尖附近的叶绿体细胞中存在许多嗜骨性颗粒，指示晚期细胞衰老。除了叶片组织内衰老相关基因的上调之外，H2O2也有大量积累。遗传作图位于SSR标记Q1和L12之间的lts2，覆盖了大约212kb的物理距离。在该地区尚未发现控制早衰叶片表型的类似基因，和随后的DNA和批量分离分析(BSA)测序分析仅在LOC_0s01g35860的外显子中鉴定出单个核苷酸取代(C-T)。这些发现将lts2突变体定位为阐明水稻叶绿素代谢和进一步功能分析该基因的有价值的遗传模型。
