随着一系列粉质胚乳突变体的研究取得重要进展,我们对于胚乳中营养物质储藏调控的认识也不断提高。完善突变体籽粒种质资源信息, 有利于准确利用遗传材料进行分子机制的研究。粉质胚乳突变体3901l来源于美国种质中心,该突变体胚乳呈现完全不透明表型。生化分析发现,该突变体α-和β-醇溶蛋白剧烈下降,同时伴随着非醇溶蛋白的大幅度升高。通过玉米SNP3072芯片进行基因分型分析,我们发现3901l基因定位于7号染色体约33M的区间。通过与o2突变体进行等位测试,确认3901l是o2的等位突变体。进一步研究表明,该突变体的O2转录本缺失了一个61-bp的外显子,造成开放阅读框移码和翻译提前终止。利用O2特异抗体检测籽粒总蛋白,发现突变体中O2蛋白完全缺失,不能检测到提前终止的O2蛋白,说明错误翻译的O2蛋白被机体快速识别并降解。因此,本研究鉴定了一个新的o2等位突变体,其突变方式与已知o2等位均不相同,完善了玉米突变体籽粒种质资源信息,也为O2蛋白稳定性研究提供新的遗传材料。
英文摘要:
Along with the significant progress made in studying of maize opaque/floury mutant, knowledge about the regulation of nutrient storage increases constantly. Improving information of mutant seed resources is beneficial to accurately use genetic materials in molecular mechanism studying. An opaque mutant 3901 was obtained from Maize Genetics Cooperation Stock Center. The mutant seeds exhibit a completely non-transparency endosperm. Biochemical analysis showed that α- and β-zein was drastically decreased, accompanied with significantly increased nonzein. Through maize SNP3072 genotyping array analysis, 3901l was mapped to a 33 Mb interval on chromosome 7. The allelism test with o2 indicated that 3901l is a new mutant allele of o2. Further studying indicated that the O2 transcript in 3901l had a 61-bp deletion of exon, causing a frame-shift in O2 Open Reading Frame and an early termination in O2 protein. Using O2-specific antibody against total protein, we found that O2 protein is completely lost in 3901l with no early terminated O2 protein detected. Thus, this study identified a new o2 mutant allele, whose mutagenesis is different from any other known o2 allele, completing the information of maize seed resource and providing new genetic material in studying the stability of O2 protein.
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