杂交水稻骨干亲本Wx基因第一内含子+1位碱基多态性分析

Polymorphisms on First Base of Wx Gene Intron 1 in Parents of Hybrid Rice

【目的】直链淀粉含量是影响稻米品质的重要因素,而编码颗粒结合型淀粉合成酶(granule-bound starch synthetase,GBSS)的蜡质基因(Wx)是影响直链淀粉含量的主效基因。本研究拟分析120份杂交水稻亲本的Wx基因第一内含子+1位碱基的多态性,以期研究其对内含子的剪接效率及Wx的表达的影响,为亲本育种筛选提供理论参考。【方法】选取120份水稻亲本材料,采用CTAB法提取基因组DNA,并以此为模版PCR扩增Wx基因片段;采用限制性内切酶Acc I对PCR产物进行酶切分析,根据琼脂糖电泳结果分析Wx基因第一内含子+1位碱基类型;同时测定其中19份亲本的直链淀粉含量、胶稠度和碱消值。【结果】PCR扩增结果显示所有材料中均可扩增出清晰且单一的目的条带;PCR产物的Acc I酶切分析结果显示,其中81份亲本的Wx基因第一内含子+1位碱基是T,即为T型,占总数的67.5%,38份亲本为G型,占总数的31.67%,而仅有1份亲本为杂合型,即GT型,占总数的0.83%。19份亲本的直链淀粉含量测定结果表明,7份G型亲本的直链淀粉含量比12份T型亲本的高,且其中6个G型亲本的直链淀粉含量平均值均超过20%。另外,测定结果表明T型亲本和G型亲本的胶稠度和碱消值差别不明显。【结论】120份杂交水稻骨干亲本的Wx基因第一内含子+1位碱基类型测定结果表明,与T型亲本相比,G型亲本的直链淀粉含量明显较高,而胶稠度和碱消值没有明显差别。

【Objective】A polymorphism analysis on the first base of Wx gene intron 1 in parents of hybrid rice was conducted to reveal the possible effect of the splicing efficiency of intron on the granule-bound starch synthetase that relates to rice grain quality for new variety breeding.【Method】PCR amplified Wx fragments from genomic DNA of 120 parents of hybrid rice were obtained.A restriction enzyme analysis on the PCR products was performed by Acc I digestion.Polymorphism of the first base of Wx gene intron 1 was analyzed by agarose gel electrophoresis.Amylose content,gel consistency,and alkali spreading value of 19 parents were determined.【Result】The target fragments could be successfully amplified from all parents using PCR.The Acc I enzyme analysis showed the first base of Wx gene intron 1 of 81 parents to be T-type,accounting for 67.5%,and that of 38 parents to be G-type,accounting for 31.67%of the total.Only one parent of heterozygous genotype was found to be GT-type among all,accounting for the remaining 0.83%.The amylose contents of the 7 G-type parents were higher than those of the 12 T-type parents,and those of the 6 G-type parents were more than 20%.No significant difference was observed on the gel consistency or alkali spreading value between the G-and T-type parents.【Conclusion】The polymorphisms of the first base of Wx gene intron 1 in 120 parents of hybrid rice were analyzed.The amylose contents in the G-type parents were higher than those in the T-type parents,but no significant differences found on the gel consistency and alkali spreading value among the 19 parents.