籼稻脂肪酶基因的遗传分析及定位

Mapping and Genetic Analysis of a Lipase Gene for indica Rice

对籼稻材料PT46(高脂肪酶活性)和WP20(低脂肪酶活性)及其F2群体进行了脂肪酶活性的定量测定和遗传分析。χ2测验结果表明,F2群体表现型分布符合1∶2∶1的孟德尔分离比,表明脂肪酶活性高低由1对单基因控制,低脂肪酶活性为隐性性状。结合SSR分子标记,以F2群体为定位群体,将脂肪酶活性基因定位在水稻第3染色体上,与SSR标记RM7和RM232之间的遗传距离分别为14.8cM和4.1cM,暂命名为la(lipase activity)。采用人工老化的方法,以种子发芽率和老化指数评价两亲本及其F2群体的耐储藏特性,结合所测定的脂肪酶活性数据进行相关性分析。结果表明,随着老化时间的延长,脂肪酶活性高的材料,发芽率降低迅速,老化指数增加很快,而脂肪酶活性较低的材料,老化指数变化相对较慢,即脂肪酶活性低的材料较耐储藏。经10、20d人工加速老化处理后的种子老化指数与种胚脂肪酶活性的相关系数分别为0.6165**和0.4703**,表明老化指数与脂肪酶活性呈显著正相关。

The quantitative and genetic analyses of lipase activity in rice embryos were conducted using two indica rice materials PT46 （containing high lipase activity in its embryos）, and WP20 （containing low lipase activity in its embryos） and their F2 population. It was found that the distribution of F2 phenotype fitted 1 ： 2 ： 1 Mendelian rule based on X^2 test of their lipase activity in rice embryos. This indicated that the activity of lipase in embryos was controlled by a single resessive gene. Moreover, the gene for lipase activity, temporarily designated as la （lipase activity） was mapped on the chromosome 3 of rice by bulk-segregation analysis of F2 population between PT46 and WP20, with the distances of 14.8 cM and 4.1 cM to SSR marker RM7 and RM232, respectively. Storability of two parents and their F2 population were evaluated with their grermination rate and aging index in artificial accelerated aging experiments. Correlation analysis showed that the seed germination rate of high lipase activity materials was decreased rapidly and the aging index was raised quickly with the increasing treatment time, whereas the aging index of low lipase activity materials was increased slowly, namely, the low lipase activity materials had better storability. After 10 and 20 days of artificial accelerated aging, the correlation coefficients were 0. 6165^＊＊and 0. 4703^＊＊ between the lipase activity and aging index, respectively, suggesting that there existed a stable positive correlation between the aging index and the lipase activity.