基于多组学的谷子后熟米色变化机制研究

米色是评价黄色小米品质重要指标，小米的黄色主要成分是类胡萝卜素。我们前期研究发现谷子后熟过程中小米米色及类胡萝卜素含量变化较大，而且品种间差异也比较大，说明后熟过程对小米米色形成有着重要的作用。因此，本研究拟对300份中国谷子核心种质资源后熟过程中的米色和类胡萝卜素含量变化进行分析，筛选出变化模式不同的品种或种质，分析其不同时期转录组、代谢组、蛋白组变化特征，利用多组学联合分析手段探索基因表达、代谢物积累与后熟米色变化的关系。将后熟米色性状数据与种质资源全基因组序列进行全基因组关联分析，结合功能注释与转录组中相关基因的表达模式以及多组学代谢通路富集信息，确定候选基因。构建候选基因过表达转基因载体及基因编辑载体，验证候选基因与谷子后熟米色的关系，探索候选基因作用机制。从而发掘后熟米色优异等位变异基因，拓展对谷子类胡萝卜素代谢机制的认知，为谷子品质分子育种及优质小米生产奠定基础。

Millet color is an important indicator to evaluate the quality of yellow foxtail millets, and the main components of the yellow color are carotenoids. Our preliminary results showed that the millet color and carotenoids content varied considerably at certain stages after harvest, the differences among varieties were large as well, indicating that post-harvest plays a crucial role in the development of the millet color. Based on these discoveries, we propose to investigate a population of 300 accessions from the Chinese core collection of foxtail millet germplasm resources, for the changes in the millet color and carotenoids content during post-harvest stages, to screen for varieties or germplasms with different change patterns. The characteristics of transcriptome, metabolome and proteome at different stages would be analyzed, and the relationship between gene expression, metabolites accumulation and the millet color variance at different post-harvest stages would be explored by using multi-omics analysis. A genome-wide association study would be conducted on the post-harvest millet color data and the whole genome sequence of the germplasm resources, and candidate genes are to be identified by combining functional annotation, the expression pattern of related genes in the transcriptome and enriched metabolic pathways from multi-omics. Over-expression transgenic vector and gene editing vector of candidate genes would be constructed to transform foxtail millet and verify the relationship between candidate genes and the millet color, and to explore the mechanisms of candidate genes. It is expected that this study would identify allelic variants useful to breeding, add to the understanding of carotenoids metabolism mechanism in foxtail millets, and lay the foundation for the molecular quality breeding of foxtail millet and production of high quality millets.