Functions of Conserved Oomycete Effector Proteins

卵霉菌植物病原体对作物和自然生态系统造成极具破坏性的疾病。人们对使卵菌成为如此成功的病原体的分子武器知之甚少。对最近完成的四种卵菌基因组的分析表明，卵菌将数十或数百种自己的“效应”蛋白输出到植物细胞内部。这些病原体效应物有望破坏植物的免疫反应，并引发其他有利于病原体的效应。然而，对卵菌效应物的分子功能几乎一无所知。本项目将研究拟南芥霜霉病病原菌Hyaloperonospora parasitica和大豆根腐病病原菌疫霉（Phytophthora sojae）这两种亲缘较远的卵菌之间保守的6对效应物的功能。预计对保守效应的关注将揭示适用于大多数卵菌病原体的见解。研究人员将进行一系列分子遗传学实验，以确定这些效应物是否能够抑制植物免疫或改变植物细胞结构或生理，以及当这些基因沉默或过度表达时，病原体引起疾病的能力是否受到影响。最后，选择一对保守蛋白进行实验，以确定其在植物细胞内的确切靶标。这些实验有望揭示重要的、广泛保守的分子策略，这些策略支持卵菌引起疾病的能力，这反过来将为更复杂的疾病控制策略开辟新的途径。该项目将为研究生和本科生提供多学科培训。该项目的某些方面将与弗吉尼亚理工大学的一个推广项目合作，该项目将在高中科学课堂上使用拟南芥反向遗传学。

Oomycete plant pathogens cause extremely destructive diseases on crops and in natural ecosystems. Little is known about the molecular weapons that enable oomycetes to be such successful pathogens. Analyses of four recently completed oomycete genomes suggest that oomycetes export dozens or hundreds of their own 'effector' proteins to the interior of plant cells. These pathogen effectors are expected to sabotage plant immune responses and trigger other effects that benefit the pathogen. However, almost nothing is known about the molecular functions of oomycete effectors. This project will investigate the functions of six pairs of effectors that are conserved between two distantly related oomycetes: the Arabidopsis downy mildew pathogen Hyaloperonospora parasitica and the soybean root rot pathogen Phytophthora sojae. It is expected that a focus on conserved effectors will reveal insights that are applicable to the majority of oomycete pathogens. The investigators will perform a series of molecular genetic experiments to determine whether these effectors are capable of suppressing plant immunity or altering plant cell structure or physiology, and whether the pathogen's ability to cause disease is affected when these genes are silenced or overexpressed. Finally, one pair of conserved proteins will be selected for experiments to identify their exact targets inside plant cells. These experiments are expected to reveal important, broadly conserved molecular strategies that underpin oomycetes' ability to cause disease, which will in turn open new avenues toward more sophisticated disease control strategies. The project will provide multidisciplinary training for graduate students and undergraduates. Some aspects of the project will be collaboratively integrated with an outreach program at Virginia Tech that uses Arabidopsis reverse genetics in high school science classrooms.