交链格孢菌是常见的植物病原真菌，对我国柑橘产业威胁重大。已有研究证明交链格孢对侵染过程中产生的ROS解毒能力与其致病性密切相关。前期研究发现病菌自身产生ROS系统，NADPH氧化酶复合体(NOX)，也参与包括ROS解毒在内的多个生物学过程。在抗氧化和抗渗透等方面，NOX一个亚基(NoxA)突变表现与Ap1、Skn7和Hog1等突变类似的表型，但对NoxA如何调控这些基因以及相应的调控层次尚不清楚。本研究拟通过构建NOX亚基的单、双和三基因突变体，结合目的信号通路中已有的关键基因的突变体，通过表型分析、qRT-PCR、基因表达谱和蛋白互作研究，明确NOX复合体与相关通路中关键基因的调控关系，并通过免疫共沉淀方法鉴定其他与NOX复合体直接互作的蛋白，最终阐明NOX介导的交链格孢菌在抗氧化、抗渗透以及产孢等信号途径中的关联调控机理。预期研究结果可为研究和开发防治链格孢菌病害的新途径提供科学依据。

Alternaria alternata is a notorious fungus that causes great losses in economically important crops, including citrus, apple, pear, rice, strawberry, tomato, broccoli, cauliflower, carrot, and potato. This fungus is capable of detoxifying the ROS generated by host during infection. Pioneering work has made significant contribution on understanding the molecular mechanisms of ROS detoxification in A. alternata. NADPH oxidase complex (NOX), however, is one of the most attractive proteins/complexes that function not only in ROS detoxification, but also in biological activities such as ROS producing, osmotic tolerance and conidiation. The mutant of NoxA, a subunit of NOX complex, showed similar impairment on ROS and osmotic tolerance compared with mutants of Ap1, Skn7 and Hog1, implying the regulation beyond. However, the mechanism how NOX mediates the crosstalk between signal pathways is still elusive. In this proposed work, we intend to construct the mutants of three NOX subunits, and extensively investigate their roles on interacting with the keys proteins in the related signal pathways by using comprehensive approaches at both transcription and protein levels. The prospective results will answer the following questions: (1) whether and how does NOX interact with AP1, SKN7 and HOG1 to orchestrate the ROS detoxification and osmotic tolerance; (2) whether the two MFS genes are functional downstream the NOX; (3) what are those proteins directly interacted with NOX. The fulfillment of this work will expand the knowledge on NOX regulating networks in eukaryotes, and also shed light on the development of novel strategies for disease control.