School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, China.
Int J Mol Sci. 2020 Dec 30;22(1):322. doi: 10.3390/ijms22010322.
The leaf is an important photosynthetic organ and plays an essential role in the growth and development of plants. Leaf color mutants are ideal materials for studying chlorophyll metabolism, chloroplast development, and photosynthesis. In this study, we identified an EMS-induced mutant, , which exhibited yellow cotyledons and true leaves that did not turn green with leaf growth. The locus was controlled by a recessive nuclear gene. The was mapped to a 166.7-kb genomic region on chromosome 2, which contains 24 predicted genes. Only one non-synonymous single nucleotide polymorphism (SNP) was found between and wt-WD1 that was located in Exon 7 of , resulting in an amino acid substitution. encodes a plastid isoform of triose phosphate isomerase (pdTPI), which catalyzes the reversible conversion of dihydroxyacetone phosphate (DHAP) to glyceraldehyde-3-phosphate (GAP) in chloroplasts. was highly expressed in the cotyledons and leaves. The mesophyll cells of the leaves contained reduced chlorophyll and abnormal chloroplasts. Correspondingly, the photosynthetic efficiency of the leaves was impaired. Identification of is helpful in elucidating the function of ptTPI in the chlorophyll metabolism and chloroplast development and understanding the molecular mechanism of this leaf color variant in cucumber.
叶片是重要的光合作用器官，在植物的生长和发育中起着至关重要的作用。叶色突变体是研究叶绿素代谢、叶绿体发育和光合作用的理想材料。本研究中，我们鉴定了一个 EMS 诱导的突变体 ，其表现为子叶和真叶呈黄色，随着叶片生长，真叶不变绿。 位点由一个隐性核基因控制。 被定位到 2 号染色体上的一个 166.7-kb 基因组区域，该区域包含 24 个预测基因。 和 wt-WD1 之间仅发现一个非同义单核苷酸多态性 (SNP)，位于 的第 7 外显子，导致氨基酸替换。 编码三磷酸甘油醛异构酶 (pdTPI) 的质体同工型，该酶在叶绿体中催化二羟丙酮磷酸 (DHAP) 到甘油醛-3-磷酸 (GAP) 的可逆转化。 在子叶和叶片中高度表达。 的叶片中叶肉细胞中的叶绿素含量减少，叶绿体异常。相应地， 叶片的光合作用效率受损。鉴定 有助于阐明 ptTPI 在叶绿素代谢和叶绿体发育中的功能，并理解黄瓜中这种叶色变体的分子机制。
