Gebremeskel Haileslassie, Umer Muhammad Jawad, Hongju Zhu, Li Bingbing, Shengjie Zhao, Yuan Pingli, Xuqiang Lu, Nan He, Wenge Liu
Henan Joint International Research Laboratory of South Asian Fruits and Cucurbits, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, China.
Department of Horticulture, Ethiopian Institute of Agricultural Research, Addis Ababa, Ethiopia.
Front Plant Sci. 2023 Apr 20;14:1152644. doi: 10.3389/fpls.2023.1152644. eCollection 2023.
Leaf color mutants are common in higher plants that can be used as markers in crop breeding and are important tools in understanding regulatory mechanisms of chlorophyll biosynthesis and chloroplast development. Genetic analysis was performed by evaluating F, F and BC populations derived from two parental lines (Charleston gray with green leaf color and Houlv with delayed green leaf color), suggesting that a single recessive gene controls the delayed green leaf color. In this study, the delayed green mutant showed a conditional pale green leaf color at the early leaf development but turned to green as the leaf development progressed. Delayed green leaf plants showed reduced pigment content, photosynthetic, chlorophyll fluorescence parameters, and impaired chloroplast development compared with green leaf plants. The locus was mapped to 7.48 Mb on chromosome 3 through bulk segregant analysis approach, and the gene controlling delayed green leaf color was narrowed to 53.54 kb between SNP130 and SNP135 markers containing three candidate genes. Sequence alignment of the three genes indicated that there was a single SNP mutation (G/A) in the coding region of in the Houlv parent, which causes an amino acid change from Arginine to Lysine. The encoded FtsH extracellular protease protein family is involved in early delayed green leaf development. The expression level of was significantly reduced in delayed green leaf plants than in green leaf plants. These results indicated that the might control watermelon green leaf color and the single SNP variation in may result in early delayed green leaf color development during evolutionary process.
叶色突变体在高等植物中很常见，可作为作物育种的标记，也是理解叶绿素生物合成和叶绿体发育调控机制的重要工具。通过对两个亲本系（绿叶色的查尔斯顿灰和叶色延迟变绿的厚绿）衍生的F1、F2和BC群体进行评估，进行了遗传分析，结果表明一个单隐性基因控制叶色延迟变绿。在本研究中，延迟变绿突变体在叶片发育早期呈现条件性淡绿色叶色，但随着叶片发育进程会转变为绿色。与绿叶植株相比，延迟变绿叶植株的色素含量、光合及叶绿素荧光参数降低，叶绿体发育受损。通过混合分组分析法将该基因座定位到3号染色体上7.48 Mb处，控制延迟变绿叶色的基因被定位到SNP130和SNP135标记之间53.54 kb的区间内，该区间包含三个候选基因。对这三个基因的序列比对表明，厚绿亲本中该基因的编码区存在一个单SNP突变（G/A），导致氨基酸从精氨酸变为赖氨酸。该基因编码FtsH细胞外蛋白酶蛋白家族，参与叶片早期延迟变绿发育过程。延迟变绿叶植株中该基因的表达水平显著低于绿叶植株。这些结果表明该基因可能控制西瓜叶色，且该基因的单SNP变异可能在进化过程中导致叶片早期延迟变绿发育。
