Early Molecular Events in Plant-Fungus Interactions

摘要本研究计划以炭疽菌（Colletotrichum gloeosporioides）和血炭疽菌（Nectria haematococca）为试验生物，阐明真菌与植物角质层相互作用的早期分子事件。这些相互作用包括第一个启动阶段，涉及真菌分生孢子与坚硬表面的接触，随后由寄主的化学信号触发萌发和附着胞形成，以及穿透寄主的角质层和果胶屏障。通过克隆分生孢子与硬寄主表面接触诱导的基因，阐明gloeosporioides与寄主相互作用的早期分子事件。我们将对炭疽菌硬表面诱导蛋白（chip）基因进行干扰，以评估其在发病机制中是否必需，并探索芯片基因产物的功能。通过克隆参与激活的转录因子，并通过鉴定其在标记基因转化酵母中的功能，以及克隆的转录因子，来阐明植物羟基脂肪酸如何激活红葡萄球菌角质酶基因的转录。果胶裂解酶在发病机制中的作用将通过评估单一和双重干扰物的毒力来测试，其中果胶诱导的pelA基因和/或宿主诱导的pelD基因被破坏。纯化和鉴定了在植物中表达pelD基因的宿主因子。这些研究结果将为角质层在发病机制中的作用提供新的见解，并可能有助于设计新的方法来控制植物真菌病害，这些病害是造成粮食和纤维生产损失的主要原因之一。

9816868KolattukudyThe overall objective of this research program is to elucidate the early molecular events involved in the interactions of fungi with the plant cuticle using Colletotrichum gloeosporioides and Nectria haematococca as test organisms. These interactions include the first priming stage that involves the contact of the fungal conidia with hard surface followed by germination and appressorium formation triggered by the host's chemical signals, and penetration of the cuticle and pectin barriers of the host. Early molecular events involved in the interaction of C. gloeosporioides with its host will be elucidated by cloning the genes induced by contact of the conidia with hard host surface. The Colletotrichum Hard surface Induced Protein (chip) genes will be disrupted to assess whether they are required for pathogenesis and the functions of the chip gene products will be explored. How hydroxyfatty acids of plants activate cutinase gene transcription in N. haematococca will be elucidated by cloning the transcription factors involved in the activation and by assessing their functions in yeast transformed with marker genes and the cloned transacting factors. The role of pectate lyase in pathogenesis will be tested by assessing the virulence of single and double disruptants in which pectin-inducible pelA gene and/or host-inducible pelD gene are disrupted. The host factor that is responsible for the in Planta expression of pelD gene will be purified and identified. The results of the proposed studies will provide new insights into the role of the cuticle in pathogenesis, and may help to devise new methods to control fungal diseases of plants that constitute one of the major causes of losses in food and fiber production.