苦荞裂壳突变体ch2遗传定位、基因克隆及分子机制研究

苦荞籽粒营养价值丰富，是药食兼用的小杂粮作物之一，而苦荞厚种壳性状导致生产加工脱壳困难且营养损失严重，因此创制新型易脱壳苦荞种质具有重要的生产实践意义。我们前期通过EMS诱变获得一个易脱壳的新型苦荞裂壳突变体cracked hull 2（ch2），但其籽粒发育过程中裂壳性状形成的分子机制目前尚不清楚。本项目拟通过比较分析突变体与亲本籽粒发育过程中种壳细胞学特征和纤维素合成相关酶活变化规律，找到与裂壳性状相关的细胞学和酶学证据；通过遗传作图精细定位裂壳基因ch2并进行克隆；采用转基因策略，解析ch2基因分子功能；利用籽粒发育过程中纤维素代谢组及转录组联合分析，揭示ch2基因调控种壳纤维素代谢及相关基因表达特征；利用基因编辑技术敲除苦荞厚种壳种质ch2等位基因，创制苦荞裂壳新种质。上述研究将阐明苦荞裂壳性状关键基因ch2控制种壳发育的分子遗传机制，为苦荞种壳性状分子育种提供理论依据和应用指导。

The grain of tartary buckwheat with abundant nutrition values is a kind of medicinal and edible minor cereal crops. However, the thick hull trait of grain led to dehull difficultly and lost lots of nutrition components during production and processing. Therefore, it is of great practical applications to develop a new easily dehulling tartary buckwheat germplasm. Previously, we bred a new type of cracked hull mutant (ch2) with a high hulling rate by EMS mutagenesis in Tartary buckwheat. But the underlying molecular mechanism on forming the cracked hull trait is still unknown during the grain development at present. In this project, we will be tried to find the cytological and enzymatic evidence related to cracked hull trait by comparing and analyzing the characteristics of cytology and enzyme activity during the grain development between the ch2 mutant and wildtype. The ch2 gene will be cloned using genetic mapping, and identified the molecular function by transgenic strategy. In further, the ch2 gene-regulating cellulose metabolism and related genes expression will be revealed by combined analysis of cellulose metabolome and grain hull transcriptome during grain development. The ch2 allele in tartary buckwheat germplasm with thick hull trait will be knocked out using gene-editing technology for breeding a new easily dehulling germplasm in the future. In summary, it will be elucidated the molecular genetic mechanism of the ch2 gene controlling the development of grain hull and provided a theoretical basis and practical instruction for molecular breeding grain hull traits of Tartary buckwheat.