利用分子标记鉴定水稻品种的Wx等位基因及其与直链淀粉含量的关系

The Genotype of Waxy Gene and Their Relationship to Amylose Content in Indica and Japonica Rice (Oryza sativa L.)

应用Wx基因的微卫星标记4 84 4 85和PCR- AccⅠ分子标记对93份籼、粳水稻品种(系)的Wx基因的多态性进行了研究,并探讨了不同基因型与直链淀粉含量的关系。4 84 4 85扩增结果表明,该微卫星标记表现为3种基因型,即Wx1 Wx1 、Wx2 Wx2 和Wx3Wx3,其中籼稻以Wx1 Wx1 和Wx3Wx3为主,粳稻以Wx2 Wx2 为主,具有Wx1 Wx1 和Wx2 Wx2 的品种(系)直链淀粉含量低,具有Wx3Wx3的品种(系)直链淀粉含量高。PCR- AccⅠ分子标记检测到两种基因型,即GG和TT型,其中GG型水稻品种的直链淀粉含量较高,TT型水稻品种的直链淀粉含量较低。两种分子标记检测结合分析,具有Wx2 Wx2 的品种(系)为TT型,Wx3Wx3的品种(系)为GG型;Wx1 Wx1 的品种(系)既有TT型又有GG型,但GG型品种的直链淀粉含量显著高于TT型品种。统计分析表明,利用微卫星标记和PCR AccⅠ分子标记检测93个水稻品种(系)中Wx基因与直链淀粉含量的相关系数分别为0 .86 7 和0 .881 ,Wx基因的遗传变异可解释这些品种(系)直链淀粉含量变异的75 %以上;因此,在水稻育种中,利用上述分子标记对辅助选择改良稻米的直链淀粉含量,提高育种效率具有重要意义。

Wx gene were highly linked with microsatellite marker named 484/485 and CAPs marker named PCR-AccⅠ. In order to estimate the different Wx genotypes and the relationships between Wx genotype and amylose content (AC), these two kinds of molecular marker were used to amplify polymorphisms of 93 rice lines including indica and japonica subspecies. The polymorphism of 484/485 amplification produced three genotypes, Wx1Wx1, Wx2Wx2 and Wx3Wx3. Wx1Wx1 and Wx3Wx3 genotypes were mainly found in indica lines, and Wx2Wx2 were mainly found in japonica lines. The correlation coefficient between Wx genotype and AC was 0.867 ** and reached a very significant level. Wx1Wx1 and Wx2Wx2 genotypes showed significantly lower amylose content and Wx3Wx3 genotype higher amylose content. A PCR-AccⅠ molecular marker was used to determine whether the first nucleotide of splice donor site of waxy intron 1 was G or T in 93 rice cultivars 1 lines collected from different areas. Most Wx1Wx1 and Wx2Wx2 genotypes were TT genotype and most Wx3Wx3 genotypes were GG genotype. The correlation coefficient between Wx genotype and PCR-AccⅠ genotype was 0.881 ** with very significant level. 75% of AC difference among the 93 lines could be explained by the variation of the Wx genotypes. All the results indicated that marker-assisted selection(MAS) is a highly efficient way for AC selection in rice quality breeding.