On January 3rd, the team of Professor Song Xiyi from the College of Agriculture of Northwest A&F University published an online titled”Identification and Applied Genetics” in Theoretical and Applied Genetics. Validation of Genetic Locus Rfk1 for Wheat Fertility Restoration in the Presence of Aegilops kotschyiCytoplasm” research article. The results of this study will help to further explore the molecular mechanism of fertility restoration of K-type cytoplasmic thermosensitive male sterile wheat, and make an important supplement to the function of plant CMS fertility restoration genes. Chen Yanru, a postgraduate student at Northwest A&F University, and Jia Yulin, a graduate student, are the co-first authors of the paper. Professor Song Xili and Associate Professor Zhang Lingli from Northwest A&F University are the co-corresponding authors.
Wheat is an important food crop. As the world’s population continues to grow and the area of arable land shrinks, increasing wheat production is of great significance to the security of global food demand. Utilizing heterosis is one of the most effective ways to increase wheat yield, and cytoplasmic male sterility (CMS) is an important way to use this approach. Among the many CMS types, the temperature-sensitive male sterility (TCMS-K) type of wheat under the cytoplasmic background of Aegilops kotschyi has obvious fertility conversion, high conversion critical temperature, complete sterility, and wide recovery sources. And other outstanding advantages, it has important research value and application prospects in the utilization of wheat heterosis.
This study used wheat TCMS-K line KTP116A, its isotype maintainer line TP116B, and restorer line LK783 carrying a pair of dominant restorer genes (Rfk1Rfk1) as materials. Construct BC1F1 backcross positioning group. Using BSA, Bulked Segregant Analysis, combined with transcriptome sequencing (RNA-seq) and KASP (Kompetitive allele-specific polymerase chain reaction) genotyping technology, the genetic locus of wheat TCMS-K fertility is restored Point Rfk1 has been finely positioned. According to the results of simple repetitive sequence (SSR) and single nucleotide polymorphism (SNP) genotyping, the restoration site was finally located on the short arm of wheat 1B chromosome, which is located in the physical candidates of approximately 26.0 Mb with markers Xnwafu_6 and Xnwafu_1B32 Within the interval. Through the screening and identification of differentially expressed genes in anthers in the candidate interval, it was revealed that TraesCS1B02G197400LC is the most likely candidate gene for Rfk1. The protein encoded by this gene contains a conserved PMEI_like domain, belonging to the pectin esterase superfamily of genes, which may be involved in the metabolic pathway of pectin, which in turn affects the male fertility of TCMS-K wheat. This finding is important for plant CMS fertility The functional annotation of the restorer gene provides an important supplement; at the same time, according to its gene structure characteristics, the corresponding marker Xnwafu_4 was developed, which can be used for marker-assisted selection of fertility restorer genes.
KTP116A is the TCMS-K wheat created by the research team, which is sown in the season (autumn or winter) in Yangling, Shaanxi, Shijiazhuang, Hebei, Guiyang, Guizhou, Yuanmou, Yunnan Sowing), showing complete male sterility, can be used for hybrid wheat seed production. In these areas, off-season sowing (spring or summer) shows male fertility and self-breeding. The one-line and dual-use characteristics of the material make it have great application potential in hybrid wheat breeding. Exploring the genetic locus of TCMS-K wheat fertility restoration and developing corresponding molecular markers for marker-assisted selection are of great significance for promoting the utilization of wheat heterosis and commercial breeding.
Full text link:https://doi.org/10.1007/s00122-020-03738-2