Xue Meihui, Li Jiahang, Liao Ruiqi, Xu Junjie, Zhou Mingwei, Yao Runpeng, Liu Zhiyong, Feng Hui, Huang Shengnan
College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China.
Tonghua Horticulture Research Institute, Tonghua, 134000, China.
BMC Plant Biol. 2025 Jan 14;25(1):49. doi: 10.1186/s12870-025-06076-x.
Chinese cabbage is a cross-pollinated crop with remarkable heterosis, and male-sterile line is an important mean to produce its hybrids. In this study, a male-sterile mutant msm7 was isolated from a Chinese cabbage DH line 'FT' by using EMS-mutagenesis.
Compared with the wild-type 'FT', the anthers of mutant msm7 were completely aborted, accompanied by the defects in leaf and petal development. Genetic analysis showed that a single recessive nuclear gene controlled the sterile phenotype of mutant msm7. Cytological observation indicated that the anther abortion of mutant msm7 was caused by the degenarated microspores and premature degradation of tapetum. MutMap and KASP analyses identified that BraA01g038270.3 C, encoding the large subunit of ribonucleotide reductase (RNR1) which involved in the biosynthesis of dNTPs, was the candidate gene, named BrRNR1. Compared with the wild-type 'FT', a G-A mutation occurred on the 4th exon of the BrRNR1 gene, leading to the premature termination of encoded amino acid in mutant msm7. Expression analysis indicated that the BrRNR1 gene was ubiquitously expressed in all organs and was significantly decreased in flower bud and anther of mutant msm7 compared with the wild-type 'FT'. Subcellular localization revealed that BrRNR1 was an endoplasmic reticulum localization protein.
Our study is the first to characterize the function of BrRNR1 gene associated with male sterility and lays a foundation for exploring the molecular mechanism of anther abortion caused by the mutation in BrRNR1 gene of Chinese cabbage.
大白菜是一种具有显著杂种优势的异花授粉作物，雄性不育系是生产其杂交种的重要手段。本研究通过甲基磺酸乙酯（EMS）诱变，从大白菜双单倍体（DH）系‘FT’中分离出一个雄性不育突变体msm7。
与野生型‘FT’相比，突变体msm7的花药完全败育，同时叶片和花瓣发育也存在缺陷。遗传分析表明，单个隐性核基因控制突变体msm7的不育表型。细胞学观察表明，突变体msm7的花药败育是由小孢子退化和绒毡层过早降解引起的。MutMap和竞争性等位基因特异性PCR（KASP）分析确定，编码参与脱氧核糖核苷酸三磷酸（dNTPs）生物合成的核糖核苷酸还原酶大亚基（RNR1）的BraA01g038270.3 C为候选基因，命名为BrRNR1。与野生型‘FT’相比，BrRNR1基因第4外显子发生了G-A突变，导致突变体msm7中编码氨基酸过早终止。表达分析表明，BrRNR1基因在所有器官中均有广泛表达，与野生型‘FT’相比，在突变体msm7的花芽和花药中表达显著降低。亚细胞定位显示，BrRNR1是一种内质网定位蛋白。
本研究首次对与雄性不育相关的BrRNR1基因功能进行了表征，为探究大白菜BrRNR1基因突变导致花药败育的分子机制奠定了基础。
