Cellular and molecular biology of verticillium diseases

点击翻译按钮获取中文摘要

Verticillium is an important plant pathogen. Each year wilt diseases cause major economic losses in hundreds of different crops worldwide. Our research program is a long-term one, focusing on the cellular and molecular mechanisms of resistance and pathogenesis associated with verticillium wilt disease of tomato. In this pathosystem resistance is usually associated with low levels of fungal colonization and minimal symptom expression in the host and susceptibility with high levels of colonization resulting in plant disease and death. However, tolerant interactions can occur in which the levels of avirulent pathogen infection are similar to compatible interactions but little or no disease develops. In fact, host plants are taller and more robust than even uninfected plants and can even protect tomatoes from more virulent races of Verticillium. However, this can lead to pathogen buildup in fields. The best method of control is breeding for resistance. However, traditional breeding approaches have been somewhat ineffective since, in most hosts, resistance is polygenic and difficult to work with. Biotechnology offers more promise but is currently hampered by lack of information about the molecular mechanisms controlling resistance, tolerance and susceptibility to Verticillium spp. Here we ask the following questions: 1) Are there distinct gene expression patterns that characterize and act as genetic fingerprints of resistance, susceptibility and tolerance and, if so, what are the genes? 2) What downstream genes are affected by the silencing or over expression of the Ve1 and/or Ve2 genes that provide resistance against virulent strains of the fungus and what are the biological consequences? 3) What other genes are critical to resistance, susceptibility and tolerance? 4) In tomato plants colonized by both avirulent (Dvd-E6) and virulent (Vd1) isolates, is there genetic interplay between Dvd-E6 and the host that could explain protection against Vd1? If so, what tomato genes are involved? The end goal is to genetically engineer healthier crops, which would be of benefit to both farmers and consumers.