两种水稻短穗突变体的形态特征、遗传分析和基因定位

Morphological Characteristics, Genetic Analysis and Gene Location of Two Short Panicle Mutants of Rice

通过辐射诱变籼稻品种明恢86,获得两种短穗突变体,分别命名为rpl1(reduced panicle length 1)和rpl2(reduced panicle length 2)。两突变体都表现为穗变短、枝梗数和穗粒数减少、枝梗缩短,但其再生植株的穗长有所恢复,与野生型的差异明显减少。等位性测验表明,rpl1和rpl2是等位突变。利用M4分离群体和基于高通量测序的分离体混合分析(BSA-seq)方法,发现rpl2中LOC_Os11g12740基因的剪接位点发生了单碱基置换突变。进一步对rpl1测序分析,发现该基因完全缺失。这说明rpl1和rpl2都是LOC_Os11g12740突变引起的,由此证实它就是目标基因。该基因与已报道的SP1是同一个基因,因此rpl1和rpl2是SP1的新等位突变,但二者的表型与已报道的3种短穗突变体并不完全相同,说明不同突变和遗传背景会影响基因功能的表现。本研究进一步验证了SP1的功能,并为深入研究其分子作用机理提供新材料。

By radiation muta genesis of the indica rice cultivar Minghui86, two short panicle mutants were obtained, named rpll （reduced panicle length 1） and rpl2 （reduced panicle length 2）, respectively. Both mutants exhibited shorter panicles, fewer panicle branches and grains, shorter branches; but the panicle lengths in their regenerated plants were partially restored, significantly diminishing their difference from the wild type. Allelism test showed that rpll and rpl2 were allelic mutations. Using M4 segregating populations and the method of high-throughput sequencing-based bulked segregant analysis （BSA-seq）, a single nucleotide substitution mutation at a splicing site of LOCOs 11 g 12740 gene was detected in rpl2. Subsequent sequencing analysis revealed that this gene was completely deleted in rpll. This indicated that both rpll and rpl2 resulted from the mutation of LOC_Osl lg12740, confirming that it was the target gene. This gene is the same as the reported SP1. Therefore, rpll and rpl2 are new mutant alleles of SP1. However, these two mutants are not exactly the same as the three previously reported mutants of SP1 in phenotype, suggesting that different mutations and genetic backgrounds may influence the expression of gene function. The results of this study further verified the function of SP1, and would provide new materials for deep research of its molecular mechanisms.