Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea.
Theor Appl Genet. 2022 Jun;135(6):1923-1937. doi: 10.1007/s00122-022-04084-1. Epub 2022 Mar 31.
Unstable Restorer-of-fertility (Rf), conferring unstable fertility restoration in the pepper CGMS system, was delimited to a genomic region near Rf and is syntenic to the PPR-like gene-rich region in tomato. The use of cytoplasmic-genic male sterility (CGMS) systems greatly increases the efficiency of hybrid seed production. Although marker development and candidate gene isolation have been performed for the Restorer-of-fertility (Rf) gene in pepper (Capsicum annuum L.), the broad use of CGMS systems has been hampered by the instability of fertility restoration among pepper accessions, especially sweet peppers, due to the widespread presence of the Unstable Restorer-of-fertility (Rf) locus. Therefore, to investigate the genetic factors controlling unstable fertility restoration in sweet peppers, we developed a segregation population (BCF) from crosses using a male-sterile line and an Rf-containing line. Segregation did not significantly deviate from a 3:1 ratio for unstable fertility restoration to sterility, indicating single dominant locus control for unstable fertility restoration in this population. Genetic mapping delimited the Rf locus to a 398 kb genomic region on chromosome 6, which is close to but different from the previously identified Rf-containing region. The Rf-containing region harbors a pentatricopeptide repeat (PPR) gene, along with 10 other candidate genes. In addition, this region is syntenic to the genomic region containing the largest number of Rf-like PPR genes in tomato. Therefore, the dynamic evolution of PPR genes might be responsible for both the restoration and instability of fertility in pepper. During genetic mapping, we developed various molecular markers, including one that co-segregated with Rf. These markers showed higher accuracy for genotyping than previously developed markers, pointing to their possible use in marker-assisted breeding of sweet peppers.
不稳定育性恢复基因（Rf）可使辣椒 CGMS 系统中的育性恢复不稳定，该基因被限定在一个靠近 Rf 的基因组区域，并且与番茄中的 PPR 样基因丰富区域是同源的。细胞质雄性不育（CGMS）系统的使用大大提高了杂交种子生产的效率。尽管已经在辣椒（Capsicum annuum L.）中对育性恢复基因（Rf）进行了标记开发和候选基因分离，但由于广泛存在不稳定育性恢复基因（Rf）位点，CGMS 系统在甜椒中的广泛应用受到限制，尤其是甜椒。因此，为了研究控制甜椒不稳定育性恢复的遗传因素，我们利用雄性不育系和含有 Rf 的系进行杂交，开发了一个分离群体（BCF）。分离群体在不稳定育性恢复到不育的比例上没有显著偏离 3:1，表明该群体中不稳定育性恢复受单个显性基因控制。遗传图谱将 Rf 基因定位在 6 号染色体上的 398 kb 基因组区域，该区域接近但不同于先前鉴定的含有 Rf 的区域。含有 Rf 的区域包含一个五肽重复（PPR）基因以及其他 10 个候选基因。此外，该区域与番茄中含有最多数量的 Rf 样 PPR 基因的基因组区域是同源的。因此，PPR 基因的动态进化可能是导致辣椒育性恢复和不稳定的原因。在遗传图谱构建过程中，我们开发了各种分子标记，包括一个与 Rf 共分离的标记。这些标记在基因分型方面比以前开发的标记具有更高的准确性，这表明它们可能在甜椒的标记辅助育种中得到应用。
