叶片是植物主要的光合器官，过早的叶片衰老限制玉米产量潜力的最大限度发挥，造成大幅减产。本研究通过甲基磺酸乙酯诱变得到了玉米叶早衰突变体les1(leaf early senescence 1)。突变体les1从七叶期开始叶片由下往上失绿黄化，生长后期叶片黄化干枯面积逐渐增大，且突变体les1地下部分生物量及籽粒变小、籽粒千粒重显著降低。与叶片黄化表型一致，研究发现突变体les1叶片中光合色素含量以及净光合速率显著降低。且突变体les1中活性氧及丙二醛大量积累,可能与叶绿素的降解及叶片早衰相关。遗传分析表明，les1的叶片早衰表型由单基因隐性突变所致；进一步通过混池建库和全基因重测序将les1的突变位点初步定位在了2号染色体。本研究对于解析玉米叶片衰老的生理机制及遗传基础有着重要意义，并为后续精细定位突变体les1的突变位点及其分子机制的研究奠定了基础。

Leaves are major photosynthetic organs. Premature senescence of leaves restricts maize yield potential, resulting to substantial reduction in maize production. In the present study, a maize leaf premature senescence mutant les1 was identified. Les1 exhibits leaf-yellowing phenotype from seven-leaf stage. During growth, the area of leaf-yellowing was increased gradually. In addition, underground biomass, length of ears, the size of seeds and thousand-grain weight were apparently reduced. In accord with the leaf-yellowing phenotype, the chlorophyll content and the net photosynthetic rate were significantly decreased in les1. ROS and MDA were also significantly accumulated in les1, which may be related to the degradation of chlorophyll and the premature senescence of les1 leaves. Moreover, genetic analysis implied that the leaf premature senescence phenotype of les1 was caused by a recessive mutation in a single locus. The mutate locus of les1 was preliminarily located on chromosome 2 through DNA mixed pool construction and whole-genome widely re-sequencing. This present research is of great significance for deciphering physiological mechanism and genetic basis underlying leaf senescence in maize. Moreover, the study lays a foundation for further fine-mapping the mutant gene and exploring its molecular mechanism in leaf senescence.

国家级大学生创新创业训练计划一般项目(202110364064)