Molecular genetics of a mutator in rice

利用伽玛射线辐照同时诱导了一个突变体和一个隐性细长颖质基因（SG）。由SG向正常颖质基因的反向突变激活的突变子在数量和质量性状的许多位点上诱发多种类型的突变。本研究通过rflp分析和rapd分析，寻找与SG密切相关的DNA maker和突变诱导突变基因，分离出这些基因并阐明其分子结构。对SG的常规连锁分析表明，SG位点与位于第7染色体上的rfs位点有密切的连锁。这一结果使我们可以估计两个RFLP制造者20和152与SG位点有关。更紧密联系的RFLP制造者将通过使用这些联系关系来识别。本研究未发现SG基因座的RAPD制造者。突变诱导的垂湿叶基因（drop - wet-leaf gene, drop -m）的RFLP连锁分析表明，drop -m位点与位于第9染色体上的RFLP maker 385有密切连锁。这强烈提示drop -m位点就是drop -2位点。利用来自玉米、Al和Cl的花青素合成基因cDNA，可以在水稻有色系和非有色系之间检测到RFLP。这表明利用这些cdna作为探针可以分离出突变诱导的着色基因。

A mutaor and a recessive slender-glume gene(SG) were simultaneously induced by gamma-ray irradiation of seeds of a rice variety Gimbozu. The mutator which is activated by a reverse mutation of SG to normal-glume gene induces various types of mutations in many loci of both quantitative and qualitative characters. In this study, RFLP-analysis and RAPD-analysis were carried out to find out the DNA maker closely linked with the SG and the mutator-induced mutant genes for isolating these genes and elucidating their molecular structurers.The conventional linkage analysis for SG showed that SG locus was closely linked with rfs locus, which is located on seventh chromosome. This result allowed to estimate that two RFLP makers of 20 and 152 were linked with SG locus. More closely linked RFLP makers will be identified by using these linkage relationships. RAPD makers for SG locus were not found out in this study.The RFLP linkage analysis for mutator-induced drooping- wet-leaf gene(drp-m) showed that drp-m locus was closely linked with RFLP maker 385, which is located on ninth chromosome. This strongly suggests that drp-m locus is drp-2 locus. By using cDNA of anthocyanin-synthetic genes derived from maize, Al and Cl, RFLP could be detected between colored and non-colored lines of rice. This indicates that mutator-induced coloring gene can be isolated by the use of these cDNAs as probes.