^(60)Co-γ射线诱导水稻卷叶突变体基因组缺失的分析

Analysis of Genomic Deletion of a Rice Rolled-leaf Mutant Mutagenized by ^(60)Co-γ Ray

为探明60Co-γ射线诱导水稻卷叶突变体γ-rl产生的原因,对早期研究中分子标记定位区间内的4个候选基因进行PCR扩增分析,发现其中的OsF MO(t)基因在γ-rl突变体中不能扩增出特异条带。通过PCR扩增和Southern杂交进一步分析,证明γ-rl基因组中存在1个包含OsF MO(t)基因的最大范围约为16.47 kb的缺失区间,该结果为电离辐射可致植物基因组DNA产生较大范围的缺失提供了一个新的确凿证据。利用FGENESH软件对此缺失区间的DNA序列进行基因预测,发现除了OsF MO(t)基因外,该缺失区间内可能还包含1个编码类似拟南芥中假设的核糖核酸酶H基因、1个编码类似人类中E2调节蛋白基因和2个未知功能基因。这些基因的缺失可能是突变体γ-rl产生的主要原因。本研究结果为γ-rl突变体相关基因的克隆及功能分析提供了理论依据。

In order to understand the mutagenic mechanism of the rolled-leaf mutant γ- rl induced by^60-γ irradiation in rice,PCR technique was used to analyze four candidate genes localized in an anchored region mapped in our prior research. The results showed that one of the candidate gene,OsF MO（ t）,was unable to produce specific amplification fragment in the mutant γ- rl. Further analysis by PCR and Southern Hybridization revealed that a large region about16. 47 kb containing the gene of OsF MO（ t）was deleted in the genome of mutant γ- rl. The results directly provide a new evidence that^60-γ ray irradiation can produce a large DNA fragment deletion in plant genome. FGENESH software was utilized to predict genes probably existed in the deleted region,and the results showed that besides OsF MO（ t）gene,the deleted region may also contain a putative ribonuclease H gene similar to that of Arabidopsis,a putative E2 regulation protein gene similar to that of homo sapiens,and other two genes with unknown function. Therefore,the deletion of these genes may be the main cause for the generation of mutation in γ- rl. The results of this study provided a theoretical basis for gene cloning and functional analysis related to the rolled leaf mutant γ- rl in rice.