水稻脆秆突变体bc-wy7的鉴定与基因定位

发布时间：2018-12-24 09:07

【摘要】：脆秆突变体是研究植物茎秆机械强度遗传机制的理想材料。本研究利用~(60)Co-γ诱变粳稻品种‘武运粳7号’(‘Wuyunjing7’,wy7),在其后代中选到1份叶片、叶鞘、茎秆等组织易折断的脆性突变体,命名为bc-wy7(brittle culm from‘Wuyunjing7’)。与野生型相比,突变体bc-wy7在全生育期期间均表现出脆性,其株高变矮、穗长变短、穗粒数减少、生育期推迟,并出现包颈的表型。茎秆细胞壁糖组分分析表明,突变体bc-wy7茎秆细胞壁中纤维素和葡萄糖含量显著降低,木糖及阿拉伯糖的含量显著增加,其他糖成分含量与野生型无显著差异。荧光显微镜观察表明,突变体bc-wy7茎秆表皮层下方厚壁组织及厚壁细胞细胞壁变薄,薄壁细胞呈现变小的趋势,但排列更紧密。遗传分析结果表明,突变体bc-wy7的脆性性状由1对隐性核基因控制,利用图位克隆技术将该基因定位于第2染色体分子标记S2-52与S2-56间180 kb的物理区段内,该区段内包含1个已克隆的与茎秆机械强度相关的基因Brittle Culm 3(BC3)。测序结果表明,突变体bc-wy7中BC3基因第9外显子处有2个碱基缺失,造成移码突变使翻译提前终止;定量RT-PCR结果表明,脆秆突变体bc-wy7茎秆和叶片中BC3基因的表达量均降低。据此推断定位的脆秆基因bc-wy7为BC3基因的等位基因。
[Abstract]:Brittle culm mutant is an ideal material for studying the genetic mechanism of mechanical strength of plant stem. In this study, the japonica rice variety 'Wuyunjing 7' ('Wuyunjing7',wy7') was induced by ~ (60) Co- 纬, and a fragile mutant was selected from its progeny, such as leaves, sheaths and stems, which were easily broken off. Named bc-wy7 (brittle culm from'Wuyunjing7'. Compared with the wild type, the mutant bc-wy7 showed brittleness during the whole growth period, the plant height became shorter, the ear length became shorter, the number of grains per spike decreased, the growth period was delayed, and the phenotype of envelop appeared. The analysis of sugar components in stem cell wall showed that the content of cellulose and glucose in the stem cell wall of mutant bc-wy7 significantly decreased, the content of xylose and arabinose increased significantly, but the other sugars content was not significantly different from that of wild type. The results of fluorescence microscope showed that the thick-walled tissue and thick-walled cell wall became thinner and the parenchyma cells became smaller but arranged more closely under the epidermis of bc-wy7 stem. Genetic analysis showed that the fragile character of the mutant bc-wy7 was controlled by a pair of recessive nuclear genes. The gene was mapped to the physical region of 180 kb between S2-52 and S2-56 by map cloning technique. There was a cloned gene Brittle Culm 3 (BC3) related to the mechanical strength of stem. The sequencing results showed that there were two base deletions in exon 9 of BC3 gene in the mutant bc-wy7, which resulted in the early termination of translation due to the frameshift mutation. The results of quantitative RT-PCR showed that the expression of BC3 gene in bc-wy7 stems and leaves decreased. It was concluded that the brittle culm gene bc-wy7 was the allele of BC3 gene.
【作者单位】：扬州大学农学院植物功能基因组学教育部重点实验室/江苏省粮食作物现代产业技术协同创新中心;中国科学院遗传与发育生物学研究所植物基因组学国家重点实验室;
【基金】：国家重点基础研究发展计划(“973”)(2013CBA01402) 江苏高校品牌专业建设工程(PPZY2015A060)~~
【分类号】：S511;Q943.2

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