Zhang Hui, Zhang Wei, Xiang Fujiang, Zhang Zhengfeng, Guo Yiming, Chen Tingzhou, Duan Feifei, Zhou Quanyu, Li Xin, Fang Miaoquan, Li Xinmei, Li Bao, Zhao Xiaoying
College of Biology, Hunan Province Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan Engineering and Technology Research Center of Hybrid Rapeseed, Hunan University, Changsha, 410082 China.
Crop Research Institute, Hunan Academy of Agricultural Sciences, Changsha, 410125 China.
Mol Breed. 2023 Nov 10;43(11):80. doi: 10.1007/s11032-023-01429-6. eCollection 2023 Nov.
Chlorophyll is one of the key factors for photosynthesis and plays an important role in plant growth and development. We previously isolated an EMS mutagenized rapeseed (), which had yellow leaf, reduced chlorophyll content and fewer thylakoid stacks. Here, we found that showed attenuated utilization efficiency of both light energy and CO but enhanced heat dissipation efficiency and greater tolerance to high-light intensity. BSA-Seq analysis identified a single nucleotide change (C to T) and (G to A) in the third exon of the and , respectively. These two genes encode the magnesium chelatase subunit I 1 (CHLI1) that catalyzes the insertion of magnesium into protoporphyrin IX, a pivotal step in chlorophyll synthesis. The mutation sites resulted in an amino acid substitution P144S and G128E within the AAA+ domain of the CHLI1 protein. Two KASP markers were developed and co-segregated with the yellow leaf phenotype in segregating F population. Loss of and by CRISPR/Cas9 gene editing recapitulated the mutant phenotype. and were located in chloroplast and highly expressed in the leaves. Furthermore, RNA-seq analyses revealed the expression of chlorophyll synthesisrelated genes were upregulated in the mutant. These findings provide a new insight into the regulatory mechanism of chlorophyll synthesis in rapeseed and suggest a novel target for improving the photosynthetic efficiency and tolerance to high-light intensity in crops.
The online version contains supplementary material available at 10.1007/s11032-023-01429-6.
叶绿素是光合作用的关键因素之一，在植物生长发育中起着重要作用。我们之前分离出一个经甲基磺酸乙酯（EMS）诱变的油菜（品种），其叶片发黄，叶绿素含量降低，类囊体堆叠减少。在此，我们发现该突变体光能和二氧化碳的利用效率降低，但热耗散效率提高，对高光强度的耐受性更强。全基因组重测序结合混合分组分析法（BSA-Seq）分析分别在该突变体的 和 的第三个外显子中鉴定出一个单核苷酸变化（C突变为T）和（G突变为A）。这两个基因编码镁螯合酶亚基I 1（CHLI1），该酶催化镁插入原卟啉IX，这是叶绿素合成中的关键步骤。突变位点导致CHLI1蛋白AAA+结构域内的氨基酸替换P144S和G128E。开发了两个竞争性等位基因特异性PCR（KASP）标记，它们在分离的F群体中与黄叶表型共分离。通过CRISPR/Cas9基因编辑敲除 和 可重现突变体表型。 和 定位于叶绿体，在叶片中高表达。此外，RNA测序（RNA-seq）分析显示，在 突变体中叶绿素合成相关基因的表达上调。这些发现为油菜叶绿素合成的调控机制提供了新的见解，并为提高作物光合效率和对高光强度的耐受性提出了新的靶点。
在线版本包含可在10.1007/s11032-023-01429-6获取的补充材料。
