类胡萝卜素使小米呈黄色，是小米重要营养物质之一。然而小米贮藏过程中类胡萝卜素降解导致褪色，严重影响小米及其加工产品营养与商品价值。我们已发现SiLOX4基因是调控小米褪色的关键基因。本项目拟通过Western-blot分析SiLOX4蛋白在不同品种、不同贮藏时期表达模式，进一步明确其与小米褪色的关系；采用CRISPR基因编辑技术和Gateway系统对SiLOX4基因在谷子中分别进行基因编辑及超表达，分析基因编辑后和超表达转基因对小米褪色的影响,验证SiLOX4基因功能；将400份核心种质资源(已有全基因组序列)的SiLOX4基因SNP/Indel与贮藏期小米褪色性状进行关联分析，筛选高度相关的变异位点；利用KASP高通量检测技术在100份山西谷子资源中验证变异位点与小米褪色性状的关联性。解析SiLOX4基因调控小米褪色的分子机制，为深入认识小米类胡萝卜素代谢以及谷子米色分子育种奠定基础。

Carotenoids, one class of the important nutrients in foxtail millet, give the millet its yellow color. The millet discoloration during the storage caused by the degradation of carotenoids seriously reduces the nutritional and commercial value of millet products. Our previous study showed that SiLOX4 was a key gene in regulating the millet discoloration. This project is proposed to use Western-blot to analyze the expression profiles of SiLOX4 among different varieties at the same storage stage and the same variety at the different storage stages. Genome editing and over-expression vectors of target gene SiLOX4 will be constructed by using CRISPR and Gateway systems respectively, and transformed into foxtail millet. The discoloration trait of the transgenic plants will be analyzed to test the function of SiLOX4 gene. In order to select the key variation loci of SiLOX4 associated with the millet discoloration, association study will be carried out between the SNP/Indel of SiLOX4 gene sequence from 400 core germplasm accessions with known genome data and phenotype of the millet discoloration during storage. KASP high-throughput sequencing technique will be used on 100 germplasm accessions from Shanxi to test the association variation loci identified above. The function of SiLOX4 gene in regulating the millet discoloration mechanism will be elucidated, which would lay the foundation for further understanding of the carotenoid metabolism and molecular breeding on millet quality in foxtail millet.