水稻早衰突变体LS-es1的基因定位及候选基因分析

衰老是植物发育末期自主发生且不可逆的适应性反应, 叶片早衰相关分子机制研究对水稻(Oryza sativa)遗传改良以及抗衰老品种培育有重要意义。LS-es1是通过EMS诱变粳稻品种TP309获得的稳定遗传的早衰突变体。对LS-es1及其野生型的表型观察和生理生化分析表明, LS-es1叶片中积累了大量活性氧且细胞死亡更多, 同时LS-es1与产量相关的农艺性状均显著下降, 这也验证了LS-es1早衰的特征。对LS-es1及其野生型幼苗进行外源激素处理, 结果表明LS-es1对水杨酸(SA)、脱落酸(ABA)和茉莉酸甲酯(MeJA)更敏感。用图位克隆方法将LS-es1基因定位在水稻第7号染色体长臂46.2 kb区间内, 该区间共包括8个开放阅读框(ORF)。对该区间内的基因进行生物信息学分析, 结果发现Os07g0275300和Os07g0276000两个候选功能基因与早衰途径相关, 并且这2个基因的表达量在野生型和突变体中差异较大。研究结果为进一步克隆LS-es1基因并深入研究其生物学功能奠定了基础。

Gene Mapping and Candidate Gene Analysis of Rice Early Senescence Mutant LS-es1

Senescence is an autonomous and irreversible adaptive response at the end of plant development. The molecular mechanism related to premature senescence of leaves is important for rice genetic improvement and breeding of anti-aging varieties. LS-es1 is a stable hereditary premature early senescence mutant obtained by EMS mutagenesis of indica variety TP309. Phenotypic observation, physiological and biochemical analysis of LS-es1 and its wild type TP309 found that LS-es1 accumulated a large amount of reactive oxygen species and more cell death, while the yield-related agronomic traits of LS-es1 were significantly decreased compared to wild type TP309, which also verified the early senescence characteristics of LS-es1. Exogenous hormone treatment of LS-es1 and TP309 seedlings showed that LS-es1 was more sensitive to salicylic acid (SA), abscisic acid (ABA) and methyl jasmonate (MeJA). The LS-es1 gene was mapped to the 46.2 kb region of the long arm of rice chromosome 7 by map-based cloning, which included 8 open reading frames (ORFs). Bioinformatics analysis of the genes in this interval revealed that two candidate functional genes, Os07g0275300 and Os07g0276000, were associated with the early senescence pathway, and the expression levels of these two genes were significantly different between wild type and mutant. The results laid the foundation for further cloning of the LS-es1 gene and in-depth study of its biological function.