水杨酸结合蛋白2在野生醋栗番茄植株盐响应中的作用研究

The yield of tomato plants is seriously affected by salty soil. The mechanisms of tomato salt tolerance should be discovered and prominent varieties be improved with high salt resistance as soon as possible. Wild halophytic tomato has long been considered as an ideal gene donor for improving salt tolerance of tomato cultivars. Extensive research has been focused on physiological and quantitative trait locus (QTL) characterization of wild tomato species. However, the research of key genes and regulatory pathways in salt response of wild tomato is very limited. In our previous work, an extremely salt-tolerant wild accession, Solanum pimpinellifolium ‘PI365967’, was compared on its gene expression profile in response to salinity with a salt-sensitive cultivated one, Solanum lycopersicum ‘Moneymaker’. It was found that a gene encoding salicylic acid-binding protein 2 (SABP2) was remarkably induced by salinity only in PI365967, suggesting a possible role in the salt response of PI365967 for SABP2, which is the key component of salicylic acid signaling. To confirm this hypothesis, full length sequences of SABP2 gene and cDNA would be cloned from PI365967 in this project, with the methyl salicylate (MeSA) esterase activity of SABP2 also characterized. Furthermore, functional analysis of SABP2 would be performed to elucidate its involvement in salt response and salicylic acid pathway by over-expressing and virus-induced gene silencing of SABP2 in tomato plantlet. The efforts might play an important role in discovering some mechanisms special to wild tomato and promoting the practical enlightenment and even transfer of such mechanisms to tomato cultivar in order to get a genetic improvement of salt tolerance.

番茄产量受高盐土壤影响严重。深入了解番茄抗盐机理，培育优良抗盐品种，刻不容缓。野生耐盐番茄一直以来都是番茄抗盐遗传改良中的理想基因供体，但对其多数的研究集中在生理水平和对数量性状位点的鉴定上，关于关键基因和调控途径的研究很少。我们通过对强耐盐性的野生品种——醋栗番茄PI365967与栽培番茄的盐响应基因表达谱进行比较研究，发现水杨酸结合蛋白2（SABP2）基因仅在醋栗番茄中受盐胁迫的强烈诱导，推测醋栗番茄的抗盐能力与SABP2参与的水杨酸途径可能相关。为证实这一假设，本项目拟克隆醋栗番茄SABP2基因，分析其蛋白的甲基水杨酸盐(MeSA)酯酶活性，并分别通过该基因的过表达和基因沉默研究其对番茄植株抗盐性和水杨酸途径相关组分的影响，以初步阐明SABP2在番茄植株盐响应过程中的作用。研究结果将对于揭示野生番茄耐盐的特殊机制，进而将其应用乃至移植到栽培番茄进行抗盐遗传改良有着重要理论和实践意义。

番茄产量受高盐土壤影响严重。深入了解番茄抗盐机理，培育优良抗盐品种，刻不容缓。野生耐盐番茄一直以来都是番茄抗盐遗传改良中的理想基因供体，但对其多数的研究集中在生理水平和对数量性状位点的鉴定上，关于关键基因和调控途径的研究很少。我们通过对强耐盐性的野生品种——醋栗番茄PI365967与栽培番茄的盐响应基因表达谱进行比较研究，发现水杨酸结合蛋白2（SABP2）基因仅在醋栗番茄中受盐胁迫的强烈诱导，推测醋栗番茄的抗盐能力与SABP2参与的水杨酸途径可能相关。为证实这一假设，本项目克隆醋栗番茄SABP2基因，分析预测其蛋白特性，并主要通过该基因的过表达研究了其对番茄植株抗盐性的影响，以初步阐明SABP2在番茄植株盐响应过程中的作用。研究结果发现SABP2对番茄耐盐性并无明显影响，可能与醋栗番茄与栽培番茄耐盐性差别不够强烈有关。