Department of Agronomy, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University, Nakhon Pathom, Thailand.
Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
Theor Appl Genet. 2024 Jun 4;137(7):146. doi: 10.1007/s00122-024-04653-6.
The major QTL Sdp1.1+ controlling seed dormancy in cowpea was finely mapped, and two CCoAOMT1 genes were identified as candidate genes for the dormancy. Seed dormancy in wild cowpea may be useful in breeding cultivated cowpea with pre-harvest sprouting resistance. A previous study identified a major quantitative trait locus (QTL) for seed dormancy, Sdp1.1+ , using the population of the cross between cultivated cowpea 'JP81610' and wild cowpea 'JP89083.' However, the molecular basis of seed dormancy in cowpea is not yet known. In this study, we aimed to finely map the locus Sdp1.1+ and identify candidate gene(s) for it. Germination tests demonstrated that the seed coat is the major factor controlling seed dormancy in the wild cowpea JP89083. Microscopic observations revealed that wild cowpea seeds, unlike cultivated cowpea seeds, possessed a palisade cuticle layer. Fine mapping using a large F population of the cross JP81610 × JP89083 grown in Thailand revealed a single QTL, Sdp1.1+ , controlling seed dormancy. The Sdp1.1+ was confirmed using a small F population of the same cross grown in Japan. The Sdp1.1+ was mapped to a 37.34-Kb region containing three genes. Two closely linked genes, Vigun03g278900 (VuCCoAOMT1a) and Vigun03g290000 (VuCCoAOMT1b), located 4.844 Kb apart were considered as candidate genes for seed dormancy. The two genes encoded caffeoyl coenzyme A O-methyltransferase 1 (CCoAOMT1). DNA sequencing and alignment of VuCCoAOMT1a and VuCCoAOMT1b between JP89083 and JP81610 revealed a single nucleotide polymorphism (SNP) causing an amino acid change in VuCCoAOMT1a and several SNPs leading to six amino acid changes in VuCCoAOMT1b. Altogether, these results indicate that VuCCoAOMT1a and VuCCoAOMT1b are candidate genes controlling physical seed dormancy in the wild cowpea JP89083.
控制豇豆种子休眠的主要 QTL Sdp1.1+被精细定位，并且鉴定出两个 CCoAOMT1 基因为休眠的候选基因。野生豇豆的种子休眠可能有助于培育具有抗收获前发芽的栽培豇豆。先前的研究使用栽培豇豆“JP81610”和野生豇豆“JP89083”杂交群体鉴定出一个主要的数量性状位点（QTL），用于种子休眠，Sdp1.1+。然而，豇豆种子休眠的分子基础尚不清楚。在这项研究中，我们旨在精细定位 Sdp1.1+位点并鉴定其候选基因。发芽试验表明，种皮是控制野生豇豆 JP89083 种子休眠的主要因素。显微镜观察表明，野生豇豆种子与栽培豇豆种子不同，具有栅栏状角质层。使用在泰国种植的 JP81610×JP89083 大 F 群体进行的精细作图表明，单个 QTL Sdp1.1+控制种子休眠。使用在日本种植的同一杂交群体的小 F 群体证实了 Sdp1.1+。Sdp1.1+被映射到一个包含三个基因的 37.34-Kb 区域。两个紧密连锁的基因 Vigun03g278900（VuCCoAOMT1a）和 Vigun03g290000（VuCCoAOMT1b），彼此相距 4.844 Kb，被认为是种子休眠的候选基因。这两个基因编码咖啡酰辅酶 A O-甲基转移酶 1（CCoAOMT1）。在 JP89083 和 JP81610 之间对 VuCCoAOMT1a 和 VuCCoAOMT1b 进行 DNA 测序和比对，发现一个单核苷酸多态性（SNP）导致 VuCCoAOMT1a 中的一个氨基酸改变，以及几个 SNP 导致 VuCCoAOMT1b 中的六个氨基酸改变。总的来说，这些结果表明，VuCCoAOMT1a 和 VuCCoAOMT1b 是控制野生豇豆 JP89083 物理种子休眠的候选基因。
