Functional analysis of the secretome of the vascular wilt pathogen Verticillium dahliae
03 / 2010 - 03 / 2013
De schimmel Verticillium dahliae veroorzaakt in ruim 200 plantensoorten een vernietigende verwelkingziekte. Tijdens infectie maakt de schimmel eiwitten aan die het immuunsysteem van de plant inactiveren. De onderzoekers gaan deze eiwitten opsporen om te achterhalen hoe ze werken.
Plant diseases cause severe crop losses worldwide with devastating effects on food and feed production. Vascular fungal pathogens are particularly notorious because they lack curative treatments and survive for decades in soil via persistent resting structures. The increased need to reduce the use of harmful pesticides and to develop novel control strategies requires in-depth understanding of the biology of vascular pathogens and the molecular mechanisms underlying pathogenicity and survival. The soil-borne vascular pathogen Verticillium dahliae causes wilt disease on >200 plant species, including economically important crops and Arabidopsis. Pathogen-secreted proteins (secretomes) generally determine the outcome of host-pathogen interactions. Bioinformatic analyses of the recently released Verticillium genome sequence predict
780 secreted proteins. When excluding the cell wall-degrading enzymes, 460 secretome genes are identified encoding potential effectors that potentially govern disease establishment. The overall objective of this project is to determine the functions of these effectors in modulation of host immunity. To this end, secretome components will be constitutively expressed in Arabidopsis and analyzed for effects on plant defense (by screening for altered susceptibility towards various pathogens) and host immune responses (by using reporters for specific defense pathways). Components that affect host immunity will be subjected to further genetic and biochemical analyses to reveal their mode of action. Secretome components may also play important roles in competition with saprophytes or to ward off mycoparasites outside the host. Therefore, the components will be screened for potential roles in microbial antagonism. To this end, secretome components will be constitutively expressed in yeast and tested for activity against various saprophytic
Microorganisms and mycoparasitic fungi. Overall, the proposed multidisciplinary approach to functionally analyze the Verticillium secretome will reveal the most potent effectors in modulation of host immunity and microbial antagonism and, in turn, provide potential novel targets for developing effective and sustainable disease control strategies.