title: A mutation in a coproporphyrinogen III oxidase gene confers growth inhibition, enhanced powdery mildew resistance and powdery mildew-induced cell death in Arabidopsis.
abstract: A gene encoding a coproporphyrinogen III oxidase mediates disease resistance in plants by the salicylic acid pathway. A number of genes that regulate powdery mildew resistance have been identified in Arabidopsis, such as ENHANCED DISEASE RESISTANCE 1 to 3 (EDR1 to 3). To further study the molecular interactions between the powdery mildew pathogen and Arabidopsis, we isolated and characterized a mutant that exhibited enhanced resistance to powdery mildew. The mutant also showed dramatic powdery mildew-induced cell death as well as growth defects and early senescence in the absence of pathogens. We identified the affected gene by map-based cloning and found that the gene encodes a coproporphyrinogen III oxidase, a key enzyme in the tetrapyrrole biosynthesis pathway, previously known as LESION INITIATION 2 (LIN2). Therefore, we designated the mutant lin2-2. Further studies revealed that the lin2-2 mutant also displayed enhanced resistance to Hyaloperonospora arabidopsidis (H.a.) Noco2. Genetic analysis showed that the lin2-2-mediated disease resistance and spontaneous cell death were dependent on PHYTOALEXIN DEFICIENT 4 (PAD4), SALICYLIC ACID INDUCTION-DEFICIENT 2 (SID2), and NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), which are all involved in salicylic acid signaling. Furthermore, the relative expression levels of defense-related genes were induced after powdery mildew infection in the lin2-2 mutant. These data indicated that LIN2 plays an important role in cell death control and defense responses in plants.
authors: College of Life Science, Shihezi University, Shihezi, 832003, Xinjiang, PR China. siweiguosongyao@163.com
authors: Chuan-yu
authors: CY
authors: Guo
authors: Guang-heng
authors: GH
authors: Wu
authors: Jin
authors: J
authors: Xing
authors: Wen-qi
authors: WQ
authors: Li
authors: Ding-zhong
authors: DZ
authors: Tang
authors: Bai-ming
authors: BM
authors: Cui
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001203:Ascomycota / Q000472:pathogenicity; D001483:Base Sequence; D016923:Cell Death / Q000235:genetics; D003304:Coproporphyrinogen Oxidase / Q000235:genetics* / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics*; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D009868:Oomycetes / Q000472:pathogenicity; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D030821:Plants, Genetically Modified; D020156:Salicylic Acid / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; C423568:EDR1 protein, Arabidopsis; D005030:Ethylenes; D054883:Oxylipins; C011006:jasmonic acid; C036216:ethylene; D003304:Coproporphyrinogen Oxidase; C585876:LESION INITIATION 2 protein, Arabidopsis; D020156:Salicylic Acid