ABC转运蛋白基因与植物的多抗耐药性密切相关,是植物抗农药机理研究的热点。克隆黄瓜ABC转运蛋白基因abca19,分析其编码蛋白的氨基酸序列、理化性质和结构,了解其在霜霉威胁迫条件下的表达规律,为abca19的研究奠定基础,为黄瓜抗农药霜霉威机理研究积累材料。以D0351为材料,根据黄瓜基因组数据库中Csa7M368750.1基因编码区全序列,应用Primer Premier 5.0软件设计引物,从黄瓜果实cDNA中克隆abca19基因的开放阅读框。定量PCR分析霜霉威胁迫处理条件下,黄瓜果实不同处理时间和黄瓜不同部位abca19的表达变化。abca19序列长度为921bp,注册到Gene Bank,登录号为KC123181。abca19编码306个氨基酸,与大豆（Glycine max）等植物abca19的同源性为80%。该蛋白是一个疏水蛋白,无跨膜结构,包含6个α-螺旋结构,无信号肽。具有蛋白激酶C磷酸化位点、N-豆蔻酰化位点、N-糖基化位点和酪蛋白激酶Ⅱ磷酸化位点等多个活性位点。霜霉威处理条件下,0.5-6h黄瓜果实处理组abca19相对表达量极显著高于对照,9-48h对照组abca19相对表达量高于处理组,但二者间差异不显著。不同处理时间点（3、9和24h）,叶片中abca19相对表达量最高,果实中其次,茎中最低。成功克隆到黄瓜abca19,该基因具有已知物种abca19的特征。霜霉威处理条件下,黄瓜果实abca19参与农药霜霉威胁迫响应,反应迅速且具有时限性。在黄瓜叶片和果实中,abca19积极参与对农药霜霉威胁迫的响应,茎中响应较弱。
Propamocarb （PM） residue in cucumber （Cucumis sativus L.） receives little attention. As is well known to all, high PM residue of cucumber could lead to increase in the violation rates of maximum residue limits and ultimately cause harm to human health. Knowledge of PM residue could help cucumber breeders in developing cultivars with low PM residue and improving cucumber quality. In this study, 32 representative cucumber accessions （26 breeding lines and six cultivars） from different regions of China were evaluated for their PM residue in fruit and leaf to provide meaning to the subjective rating, which was highly correlated with PM residual content of fruit （r=0.97） and leaf （r=0.94）. In addition, PM residual content of North China ecotype was the highest and Pickling ecotype was the lowest in fruit and leaf of cucumber. The leaf had significantly higher （P〈0.01） PM residual content than the fruit, and poor correlation between leaf and fruit was represented. This study verified PM residual relationship between fruit and leaf, and laid the foundation for further identification of germplasm resources and breeding of new varieties for low PM residue of cucumber.
