Ethylene and Pathogen Infection Responses in Tomato and Arabidopsis

植物与致病病原体的相互作用一般分为两种类型：亲和性和不亲和性。不相容导致抵抗力，相容导致疾病。在缺乏抗性反应的情况下，疾病症状可能会传播，导致植物受到严重损害或死亡。对不能合成乙烯、水杨酸(SA)或茉莉酸(JA)的突变体进行分析，确定了亲和番茄过程中病害症状发展的多阶段序列：病原菌相互作用。所有这三种植物激素的合成对于完全症状的发展是必不可少的。疾病的传播与依赖乙烯的SA的积累有关。JA在这一系列事件中的地位尚未确定。我们打算阐明这三种激素是如何控制症状发展的。实验将在分子遗传水平上确定乙烯、水杨酸和茉莉酸在番茄症状发展中的作用。通过激素定量和加法的组合，将确定这三种激素相对于彼此的作用顺序。将进行微阵列分析，以确定从感染到细胞死亡的进程的组成部分。这些实验将得到有关拟南芥：黄单胞菌相互作用的工作的补充。在拟南芥中，各种激素受体上的乙烯不敏感突变体对疾病症状有不同程度的缓解作用。这一结果表明这五种乙烯受体具有不同的功能。分子和遗传方法将被用来定义差异反应。这些实验有可能确定迄今为止被认为是冗余受体家族的独特功能。

The interactions of plants and disease-causing pathogens generally fall into two types: compatible and incompatible. Incompatibility leads to resistance while compatibility leads to disease. In the absence of a resistant response, disease symptoms can spread, leading to severe damage or death of the plant. Analysis of mutants unable to synthesize ethylene, salicylic acid (SA) or jasmonic acid (JA), defined a multistage sequence of disease symptom development during a compatible tomato:pathogen interaction. Synthesis of all three phytohormones is essential for complete symptom development. The spread of disease is associated with an ethylene-dependent accumulation of SA. The position of JA within this cascade of events has yet to be determined. We intend to elucidate how these three hormones control symptom development. Experiments will define at a molecular genetic level the roles of ethylene, SA and JA in symptom development in tomato. Through a combination of hormone quantitation and add-backs, the order of action of the three hormones relative to one another will be determined. Microarray analyses will be performed to identify components of the progression from infection to cell death. These experiments will be complemented by work involving Arabidopsis:Xanthomonas interactions. In Arabidopsis, there is differential attenuation of disease symptoms with ethylene insensitive mutants in the various hormone receptors. This result suggests distinct functions for the five ethylene receptors. Molecular and genetic approaches will be used to define the differential responses. These experiments have the potential to identify unique functions for what has heretofore been considered a redundant receptor family.