A Rice PECTATE LYASE-LIKE Gene Is Required for Plant Growth and Leaf Senescence
A Rice PECTATE LYASE-LIKE Gene Is Required for Plant Growth and Leaf Senescence
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植物生长和叶子衰老需要水稻果胶酸裂解酶样基因
DOI：
10.1104/pp.16.01625
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发表时间：
2017-06-01
期刊：
影响因子：
7.4
通讯作者：
Zeng, Dali
中科院分区：
文献类型：
--
作者：
Leng, Yujia;Yang, Yaolong;Zeng, Dali
为了更好地理解单子叶植物生长和叶片衰老背后的分子机制，我们鉴定了一个表现出矮化和早衰叶表型的突变体，称为矮化和早衰叶1（del1）。组织学分析表明，异常生长是由细胞数量减少引起的。进一步的研究表明，细胞数量的下降在del 1细胞周期的影响。生理分析，透射电子显微镜，和TUNEL检测表明，叶片衰老是由活性氧的积累。DEL1基因的克隆使用地图为基础的方法。它被证明编码一个果胶酸裂解酶（PEL）的前体，含有PelC结构域。DEL1含有PEL的所有保守残基，与植物PelC有很强的相似性。DEL1在所有组织中表达，但主要在伸长组织中表达。功能分析表明，DEL1的突变降低了总的PEL酶活性，增加了甲基化的同型半乳糖醛酸的程度，并改变了细胞壁的组成和结构。此外，转录组分析表明，一组细胞壁功能和衰老相关基因的表达被改变的del 1植物。我们的研究表明，DEL1参与维持正常细胞分裂和诱导叶片衰老。这些发现揭示了一个新的分子机制，植物生长和叶片衰老介导的果胶裂解酶样基因。
To better understand the molecular mechanisms behind plant growth and leaf senescence in monocot plants, we identified a mutant exhibiting dwarfism and an early-senescence leaf phenotype, termed dwarf and early-senescence leaf1 (del1). Histological analysis showed that the abnormal growth was caused by a reduction in cell number. Further investigation revealed that the decline in cell number in del1 was affected by the cell cycle. Physiological analysis, transmission electron microscopy, and TUNEL assays showed that leaf senescence was triggered by the accumulation of reactive oxygen species. The DEL1 gene was cloned using a map-based approach. It was shown to encode a pectate lyase (PEL) precursor that contains a PelC domain. DEL1 contains all the conserved residues of PEL and has strong similarity with plant PelC. DEL1 is expressed in all tissues but predominantly in elongating tissues. Functional analysis revealed that mutation of DEL1 decreased the total PEL enzymatic activity, increased the degree of methylesterified homogalacturonan, and altered the cell wall composition and structure. In addition, transcriptome assay revealed that a set of cell wall function- and senescence-related gene expression was altered in del1 plants. Our research indicates that DEL1 is involved in both the maintenance of normal cell division and the induction of leaf senescence. These findings reveal a new molecular mechanism for plant growth and leaf senescence mediated by PECTATE LYASE-LIKE genes.