Graduate School of Agriculture, Kindai University, Nara, Nara, 631-8505, Japan.
Faculty of Agriculture, Kindai University, Nara, Nara, 631-8505, Japan.
Theor Appl Genet. 2022 Jul;135(7):2437-2452. doi: 10.1007/s00122-022-04125-9. Epub 2022 Jun 2.
A begomovirus resistance gene Pepy-2 encoding the DFDGD-Class RNA-dependent RNA polymerase 3a was identified in pepper (C. annuum) through the forward and reverse genetic analyses. In several countries throughout the world, the whitefly-transmitted begomovirus causes massive yield losses in pepper (Capsicum spp.) production. Although introgression of the genetic resistance against begomovirus to commercial cultivars is strongly required, the recently discovered recessive resistance gene pepy-1, which encodes the messenger RNA surveillance factor Pelota, is the only begomovirus resistance gene identified in Capsicum so far. In this study, we fine-mapped another begomovirus resistance gene from PG1-1 (C. annuum), which is resistant to pepper yellow leaf curl Indonesia virus (PepYLCIV) and pepper yellow leaf curl Aceh virus (PepYLCAV), to further speed up the marker-assisted breeding of begomovirus resistance in peppers. A single dominant locus, Pepy-2, conferring resistance against PepYLCIV in PG1-1 was identified on chromosome 7 by screening recombinants from the F and F segregating populations derived from a cross between PG1-1 and begomovirus susceptible SCM334. In the target region spanning 722 kb, a strong candidate gene, the RNA-dependent RNA polymerase 3a (CaRDR3a), was identified. The whole-genome and transcriptome sequences of PG1-1 and SCM334 revealed a single Guanine (G) deletion in CaRDR3a first exon, causing a frameshift resulting in loss-of-function in SCM334. In addition, multiple loss-of-function alleles of CaRDR3a were identified in the reference sequences of C. annuum, C. chinense, and C. baccatum in the public database. Furthermore, virus-induced gene silencing of CaRDR3a in PG1-1 resulted in the loss of resistance against PepYLCIV. PG1-1 and the DNA marker developed in this study will be useful to breeders using Pepy-2 in their breeding programs.
通过正向和反向遗传学分析，在辣椒（C. annuum）中鉴定出一个编码 DFDGD 类 RNA 依赖性 RNA 聚合酶 3a 的 Begomovirus 抗性基因 Pepy-2。在世界上许多国家，粉虱传播的 Begomovirus 导致辣椒（Capsicum spp.）产量大量损失。尽管强烈需要将针对 Begomovirus 的遗传抗性导入商业品种，但迄今为止在 Capsicum 中发现的唯一 Begomovirus 抗性基因是最近发现的隐性抗性基因 pepy-1，它编码信使 RNA 监测因子 Pelota。在这项研究中，我们从 PG1-1（C. annuum）中精细定位了另一个 Begomovirus 抗性基因，该基因对辣椒黄卷叶印度病毒（PepYLCIV）和辣椒黄卷叶 Aceh 病毒（PepYLCAV）具有抗性，以进一步加速辣椒中 Begomovirus 抗性的标记辅助育种。通过筛选 PG1-1 与感病 SCM334 杂交衍生的 F 和 F 分离群体中的重组体，在染色体 7 上鉴定出一个单个显性位点 Pepy-2，该位点赋予 PG1-1 对 PepYLCIV 的抗性。在跨越 722 kb 的目标区域中，鉴定出一个强候选基因，即 RNA 依赖性 RNA 聚合酶 3a（CaRDR3a）。PG1-1 和 SCM334 的全基因组和转录组序列显示 CaRDR3a 第一外显子中单个鸟嘌呤（G）缺失，导致移码，从而导致 SCM334 功能丧失。此外，在公共数据库中，在 C. annuum、C. chinense 和 C. baccatum 的参考序列中鉴定出多个 CaRDR3a 的功能丧失等位基因。此外，PG1-1 中 CaRDR3a 的病毒诱导基因沉默导致对 PepYLCIV 的抗性丧失。PG1-1 和本研究中开发的 DNA 标记将有助于育种者在其育种计划中使用 Pepy-2。
