State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China.
Department of Plant Sciences, University of Idaho, Moscow, ID, 83844, USA.
Theor Appl Genet. 2019 Aug;132(8):2413-2423. doi: 10.1007/s00122-019-03363-8. Epub 2019 Jun 17.
Plant male sterility is a valuable trait in breeding and hybrid seed production. The barley male-sterility gene msg26 was mapped to a 0.02-cM region that anchors to a 506-kb low-quality assembly between two cleaved amplified polymorphic sequence (CAPS) markers, SP1M14 and SP1M49. The barley gene HORVU4Hr1G074840, which encodes a putative cytochrome P450 CYP704B protein, appears to be a strong candidate for the MSG26 trait. Barley (Hordeum vulgare L.) is an important cereal crop worldwide. Traditional breeding in barley is time-consuming and labor-intensive. The use of male-sterile genotypes may significantly improve the efficacy of hybrid breeding and seed production. The barley accession 'GSHO745' is a spontaneous male-sterile mutant from the barley variety, 'Unitan'. The male sterility in 'GSHO745' is controlled by the recessive gene, msg26 (originally named as ms-u). We revealed that the barley plants homozygous for msg26 proceeded normally through Meiosis II until the tetrad stage, but became fully defective in the late uninucleate microspores and developed pollen-less anthers. Using seven barley F populations, we mapped MSG26 to a 0.02-cM region that anchored to a 506-kb low-quality assembly between two cleaved amplified polymorphic sequence markers, SP1M14 and SP1M49. The HORVU4Hr1G074840 gene that encodes a putative cytochrome P450 protein (CYP704B) was identified as the most plausible candidate for MSG26. First, HORVU4Hr1G074840 is located in a collinear region of the rice CYP704B2 and the maize CYP704B1. Both of these genes are essential for male gamete production. Second, the male-sterile allele of HORVU4Hr1G074840 in GSHO745 contained a 4-bp deletion in the last exon. The resulting frame shift causes a Gly436Gln substitution, scrambles the sequence of the remainder of the protein, and forms a new termination site at the 70th triplet of the shifted reading frame. We thus called the variant protein CYP704B:p.G436Qfs*70. Third, the barley HORVU4Hr1G074840 gene was specifically expressed in anthers. Altogether, HORVU4Hr1G074840 represents a strong candidate for MSG26 in barley.
植物雄性不育是在育种和杂交种子生产中的一个有价值的特征。大麦雄性不育基因 msg26 被定位到一个 0.02-cM 区域，该区域与两个切割扩增多态性序列 (CAPS) 标记 SP1M14 和 SP1M49 之间的 506-kb 低质量组装锚定。大麦基因 HORVU4Hr1G074840 编码一个假定的细胞色素 P450 CYP704B 蛋白，似乎是 MSG26 性状的一个强有力的候选基因。大麦（Hordeum vulgare L.）是世界范围内一种重要的谷类作物。传统的大麦育种既耗时又费力。雄性不育基因型的使用可能会显著提高杂交育种和种子生产的效率。大麦品系“GSHO745”是来自大麦品种“Unitan”的自发雄性不育突变体。“GSHO745”中的雄性不育受隐性基因 msg26（最初命名为 ms-u）控制。我们揭示了 msg26 纯合的大麦植株在减数分裂 II 过程中正常进行，直到四分体阶段，但在后期单核小孢子中完全缺陷，并发育出无花粉的花药。利用七个大麦 F 群体，我们将 MSG26 定位到一个 0.02-cM 区域，该区域与两个切割扩增多态性序列标记 SP1M14 和 SP1M49 之间的 506-kb 低质量组装锚定。编码一个假定的细胞色素 P450 蛋白（CYP704B）的 HORVU4Hr1G074840 基因被确定为 MSG26 的最合理候选基因。首先，HORVU4Hr1G074840 位于水稻 CYP704B2 和玉米 CYP704B1 的共线性区域。这两个基因对于雄性配子的产生都是必不可少的。其次，GSHO745 中的 HORVU4Hr1G074840 雄性不育等位基因在最后一个外显子中含有 4-bp 缺失。由此产生的移码导致 Gly436Gln 取代，打乱了剩余蛋白质的序列，并在移码阅读框的第 70 个三联体处形成一个新的终止位点。因此，我们将变体蛋白称为 CYP704B:p.G436Qfs*70。第三，大麦 HORVU4Hr1G074840 基因在花药中特异性表达。总之，HORVU4Hr1G074840 是大麦中 MSG26 的一个强有力的候选基因。
