利用RT-PCR技术从甘蓝型油菜耐淹品系WR-4中克隆获得BnADH3基因,其完整开放阅读框为1137 bp。该基因编码379个氨基酸,与甘蓝BoADH3基因和拟南芥AtADH3基因高度同源,同源性分别达到96%和91%。利用定量RT-PCR检测BnADH3基因在油菜耐淹系WR-4和不耐淹系WR-24中的表达表明,在淹水处理下该基因表达受到一定的诱导,淹水处理6 h后表达开始上调,说明BnADH3基因在油菜耐淹机制中发挥作用；将其转化到模式生物拟南芥中,采用幼苗淹水3 d后去水处理,测定表明转基因株系叶片和根系中乙醇脱氢酶活性均高于野生型；生长4周和6周的拟南芥植株淹水3 d后的表型显示,BnADH3的表达可增强拟南芥对淹水胁迫的耐性,处理的T2代转基因幼苗大部分恢复,但野生型幼苗枯死；调查表明,淹水5 d后野生型植株的存活率为26.7%,转基因株系ADH33和ADH44的存活率分别为80.0%和66.7%。%BnADH3 gene was cloned from submergence-tolerant line WR-4 ofBrassica napus L. using RT-PCR technique. The full-length open reading frame is 1137 bp, encoding 379 amino acids. Homology analysis showed thatBnADH3gene was highly homologous toBoADH3 fromBrassica oleracea andAtADH3 fromArabidopsis, with the 96% and 91% similarity, respectively. Quantitative RT-PCR assay was carried out to compareBnADH3 expression between the submergence-tolerant line WR-4 and the submergence-susceptible line WR-24. The result showed that theBnADH3 expression was induced by submergence and the up-regulation occurred since 6-hour post treatment. TheBnADH3 transgenicArabidopsis was obtained and the transgenic seed-lings were exposed to three-day submergence stress. Overexpression of BnADH3 resulted in higher ADH activity in leaf and root of transgenicArabidopsis compared to that of the wild type. The four- and six-week seedlings of T2 generation showed higher tolerance to submergence stress after three-day submergence treatment and most T2 seedlings were recovered with nor-mal growth when the stress was relieved for three days. However, the wild-type seedlings withered until death. After five-day submergence, the survival ratios were 26.7% for the wild type, 80.0% for transgenic line ADH33, and 66.7% for transgenic line ADH44.
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