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。在上次资助期间，我们已经确认并初步鉴定了巴勒斯坦番茄品种P2的生殖耐热特性。此外，我们获得的证据表明，该品种在受精和坐果方面也表现出优异的耐盐性。在上一个资助期间，一个新兴的新概念是基于对拟南芥中依赖蒸腾的耐盐途径的确定。在这方面，我们不仅确定了CBL-CIPK复合物，而且确定了ROP GTPase作为该途径迄今未知的组分。我们成功地从番茄中鉴定并组装了同源的CBL-CIPK-RBOHF模块，并启动了遗传学方法来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的ROP11是蒸腾依赖的耐盐性的一个组成部分，我们同样对番茄中的小GTPase SlROP9 （AtROP11的同源物）进行了表征。基于这些成果，我们打算在申请的延期期内实现两个具体目标：(i)我们打算进一步表征P2品种的耐热生殖性状（正午耐热性和对夜间高温的潜在耐受性）的表型特征，并从遗传学上确定这种非生物胁迫性状的潜在遗传原因。同样，我们希望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，我们将结合体外和体内的方法，如雌蕊摄食试验，详细表征P2的耐高温和耐盐表型。随后，我们将使用已经存在的F2群体进行大规模表型分析，初始基于RAPD的QTL定位/验证，最后使用NGS方法进行基于图谱的克隆。（ii）此外，我们将研究我们在上一期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。这里的重点将放在转基因番茄系的进一步产生和表征上，以阐明这些蛋白质的功能和生理作用。总之，这些方法将显著增强我们对番茄耐高温耐盐机制和信号网络的理解。

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.