RESUMEN
Photo-(thermo-) sensitive genic male-sterile line is the key component of two-line hybridization system in foxtail millet (Setaria italica), but the genetic basis of male sterility in most male-sterile lines is still unclear. In the present study, a large F2 population was developed derived from a cross between the photo-(thermo-) sensitive male-sterile line A2 and the fertile-line 1484-5. Thirty plants with extreme high and extreme low fertility were selected from the population to construct a sterile DNA pool and a fertile DNA pool, respectively. Sequencing both DNA pools and data analysis revealed that two QTLs conferred male-sterility, qSiMS6.1 with a major effect and qSiMS6.2 with a minor effect, on chromosome 6. Both QTLs exhibited complete dominance. The major QTL, qSiMS6.1, was delimited to a 186-kb interval between the markers SiM20 and SiM9 by the joint analysis of QTL-seq and QTL mapping with SSR and structure variation markers. Millet_GLEAN_10020454 in this region is the most likely candidate gene for qSiMS6.1 since it is predicted to encode a male-sterile 5 like protein. These results lay a solid foundation for qSiMS6.1 cloning and provided gene resources for breeding new male-sterile lines. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-021-01269-2.
RESUMEN
Metabolomics aims at determining a sample's metabolites profile and hence provides a straight functional statement of an organism's physiological condition. Here, we investigated comprehensive profiling, natural variation and species-specific accumulation of both primary and secondary metabolites in foxtail millet using LC-MS, and inheritance patterns of metabolome in millet hybrids. The application of a broad target metabolomics method facilitated the simultaneous identification and quantification of more than 300 metabolites. The metabolic analysis of these compounds, such as flavonoids, phenolamides, hydrocinnamoyl derivatives, vitamins and LPCs, revealed their developmentally controlled accumulation, and natural variation in different tissues/varieties. Species-specific accumulation of secondary metabolites was observed based on a comparative metabolic analysis between millet and rice, such as flavonoid O-rutinosides/neohesperidosides and malonylated flavonoid O-glycosides. In analyzing the metabolic variations between hybrid progenies and their parental lines, including a photothermo-sensitive genic male sterility line and five Zhangzagu varieties, metabolic overdominant, and dominant patterns of inheritance could be observed. For example, hydrocinnamoyl derivatives and feruloylated flavonoids were identified as over-parent heterosis (overdominant) metabolites in milet hybrids. Our work paves the way for developing predictors of hybrid performance and the future analysis of the biosynthesis and regulation of relevant metabolic pathways in millet.