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在60 Co-γ射线辐射诱变籼稻中恢8015的突变体库内发现了一个花器官发育突变体,暂命名为开颖不育突变体ohms1(open hull and male sterile 1)。ohms1突变体表现为颖花开裂,在雄蕊和柱头之间形成类似内外稃的结构,使得突变体的颖花形成类似“三齿稃”状的三个颖壳,小穗完全不育,花粉育性为60%~70%,但自交不结实。遗传分析和基因定位结果表明,ohms1受一对隐性单基因控制,位于第3染色体短臂KY2和KY29标记之间,物理距离约42kb,该区域包含4个开放阅读框ORFs。进一步序列分析发现,突变体中一个编码MADS盒的基因LOC_Os03g11614的第5内含子末位碱基由A突变为G。酶切实验和cDNA测序证实,该基因的第5内含子未被剪切,致使该基因的第6外显子所编码的14个氨基酸完整缺失,但并未造成该蛋白MADS结构域的改变或移码。qRT-PCR结果显示,突变体中OsMADS1基因的表达水平显著降低,水稻开花调控因子和内外稃发育调控基因的表达量也发生了显著变化。说明该基因对水稻花器官发育尤其是内外稃发育和小花原基的分化具有重要作用。
A floral organ development mutant was found in a mutant pool of 8015 indica rice, which was induced by 60 Co-γ-ray irradiation, and tentatively named as open hull and male sterile 1. The ohms1 mutant showed spikelets cracking, forming a structure similar to that of the outer and outer stigma between the stamens and stigma, making the spikelets of the mutant form three glume shells similar to the “Tridentate Trichomes”, the spikelets were completely sterile, Pollen fertility of 60% to 70%, but not self-fertility. Genetic analysis and gene mapping showed that ohms1 was controlled by a pair of recessive single genes and located between chromosomes KY2 and KY29 on chromosome 3 with a physical distance of about 42 kb. This region contains four open reading frame ORFs. Further sequence analysis revealed that the fifth intron base of LOC_Os03g11614, a gene encoding MADS box, mutated from A to G. Enzyme digestion and cDNA sequencing confirmed that the fifth intron of the gene was not cleaved, resulting in the complete deletion of the 14 amino acids encoded by exon 6 of the gene, but did not result in the alteration of the MADS domain of the protein Or frame shift. The results of qRT-PCR showed that the expression level of OsMADS1 gene in the mutant was significantly reduced, and the expression regulation of flowering regulators and the regulation genes of both the ectocarpa and pombe in rice also changed significantly. The results indicated that this gene plays an important role in the development of floral organs in rice, especially the development of inflorescences and the differentiation of inflorescence primordia.