Mechanisms of abiotic stress responses in tomato (Solanum lycopersicum)

该项目的长期目标是促进我们对番茄耐热性和耐盐性的分子机制和潜在遗传成分的理解。在上一个资助期间，我们已经确认并初步表征了巴勒斯坦番茄栽培品种P2的生殖耐热性性状。此外，我们获得的证据表明，该品种似乎也表现出特殊的耐盐性施肥和坐果。在上一个资助期间出现的一个新概念是基于拟南芥中蒸腾依赖性耐盐途径的鉴定。在这方面，我们不仅确定了CBL-CIPK复合物，而且还确定了ROP GT3作为迄今为止未知的该途径的组分。我们成功地从番茄中鉴定和组装了同源CBL-CIPK-RBOHF模块，并启动了遗传方法，以研究这些蛋白质的分子和生理功能。基于我们从拟南芥中鉴定出ROP 11作为蒸腾依赖性耐盐性的组分，我们类似地进行了来自番茄的小GTTRs SlROP 9（AtROP 11的同源物）的表征。基于这些成就，我们打算在请求的延长期内追求两个具体目标：（i）我们打算进一步表型表征P2品种的耐热性生殖性状（中午耐热性和对升高的夜间温度的潜在耐受性），并从遗传学上鉴定这种非生物胁迫性状的潜在遗传原因。同样地，我们想要阐明我们在该品种中观察到的生殖耐盐性的特征和遗传原因。为此，我们将结合联合收割机在体外和体内的方法，如雌蕊喂养试验，详细表征耐热和耐盐表型的P2。随后，我们将使用已经存在的F2群体进行大规模的表型分析，初步的基于RAPD的QTL定位/验证，最后使用NGS方法进行图位克隆。(ii)此外，我们将研究我们在上一个资助期间组装的番茄CBL-CIPK-RBOH-ROP模块的分子机制和生理功能。在这里，重点将是进一步生成和表征的转基因番茄线，允许阐明这些蛋白质的功能和生理作用。总之，这些方法应显着提高我们的理解的机制和信号网络的基础上的耐热性和耐盐性的番茄。

The long-term goal of this project is to advance our understanding of the molecular mechanisms and the underlying genetic components that function in heat and salt stress tolerance in tomato. During the last funding period we have confirmed and initially characterized a generative heat tolerance trait of the Palestinian tomato cultivar P2. Moreover, we obtained evidence that this cultivar appears to exhibit also exceptional salt tolerance with respect to fertilization and fruit set. An emerging new concept during the last funding period was based on the identification of a transpiration dependent salt tolerance pathway in Arabidopsis. In this regard we identified not only a CBL-CIPK complex but also a ROP GTPase as so far unknown components of this pathway. We succeeded in identifying and assembling a homologous CBL-CIPK-RBOHF module from tomato and initiated genetic approaches to enable the study of the molecular and physiological function of these proteins. Based on our identification of ROP11 from Arabidopsis as a component of transpiration dependent salt tolerance we similarly performed the characterization of the small GTPase SlROP9 (the homolog of AtROP11) from tomato. Based on these achievements we intend to pursue two specific aims during the requested extension period:(i) We intend to further phenotypically characterize the heat tolerant generative trait of the P2 variety (midday heat tolerance and potential tolerance to elevated night temperatures) and to genetically identify the underlying genetic cause(s) for this abiotic stress trait(s). Similarly, we want to elucidate the characteristics and genetic causes of the generative salt tolerance that we observed in this variety. To this end we will combine in vitro and in vivo approaches, like pistil feeding assays, for detailed characterization of the heat and salt tolerant phenotypes of P2. Subsequently, we will use the already existing F2 populations for a large-scale phenotyping, initial RAPD based QTL mapping/verification and finally a map-based cloning using NGS approaches. (ii) Moreover, we will investigate the molecular mechanisms and physiological function of the tomato CBL-CIPK-RBOH-ROP module that we have assembled during the last funding period. Here the focus will be on the further generation and characterization of genetically modified tomato lines that allow to elucidate the function and physiological roles of these proteins. Together, these approaches should significantly enhance our understanding of the mechanisms and signaling networks that underlie heat and salt tolerance in tomato.