糯性水稻中蜡质基因第1内含子的剪接活性

Studies on the Splicing Ability of Wx Gene Intron 1 in Glutinous Rice

以前的研究结果表明 ,非糯性的稻米中直链淀粉的含量与各品种中蜡质基因 (Wx)第 1内含子被剪接的效率有关 ,即剪接效率高的品种直链淀粉含量也高。为弄清糯米中不含直链淀粉是否也与此内含子剪接效率有关系 ,构建了蜡质基因启动子 (来自籼稻品种2 32 )、蜡质基因第 1内含子 [来自籼稻品种 2 32 (高直链淀粉含量的品种 )或粳稻品种寒丰 6 36 6 (中、低直链淀粉含量的品种 ) ]与GUS报告基因组成的两种嵌合基因 ,将含有这两种嵌合基因的质粒分别转化进粳性糯稻品种奉糯 5 93中 ,同时还分别转化进非糯性的籼稻品种特青和粳稻品种中花 11中作为对照 ,测定它们的抗性愈伤组织与转基因植株未成熟种子胚乳中的GUS酶活性。结果表明与在非糯性的籼稻和粳稻中一样 ,这两种嵌合质粒在不合成直链淀粉的糯稻中也有相当水平的表达。从此结果可以推测 ,糯稻品种有从嵌合基因的转录本中剪接蜡质基因第 1内含子的正常能力 。

Two chimeric plasmids with Wx gene promoter(from O.sativa subsp. indica cv. 232)、 Wx first intron (from O.sativa subsp. indica cv. 232 or subsp. japonica cv. Hanfeng) and coding region of GUS reporter gene were constructed(Fig. 1), then they were introduced into glutinous rice O.sativa subsp. japonica cv.Fengnuo 593. These two chimeric genes were also introduced into nonglutinous indica rice Teqing and japonica rice Zhonghua11 to serve as control. The GUS activities in the transformed calli(Fig. 2) and the immature seeds of transgenic plants(Fig. 3) were determined. The data show that these two plasmids conferred a level of GUS activities on glutinous rice as high as that on nonglutinous rice, which suggests that glutinous rice has normol activity to splice intron 1 from transcript of waxy gene,and the lack of amylose in grains of glutinous rice may be caused by other mutations located in Wx intron 1.