A Cdc42 homolog in Colletotrichum gloeosporioides regulates morphological development and is required for ROS-mediated plant infection

• Published in: Current genetics 2018-10, Vol.64 (5), p.1153-1169
• Main Authors: Wang, Xiaolian, Xu, Xin, Liang, Yingmei, Wang, Yonglin, Tian, Chengming
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological - genetics; Anthracnose; Appressoria; Biochemistry; Biomedical and Life Sciences; cdc42 GTP-Binding Protein - genetics; cdc42 GTP-Binding Protein - metabolism; Cdc42 protein; Cell Biology; Cell Wall - metabolism; Cell walls; Chitin; Clonal deletion; Colletotrichum - genetics; Colletotrichum - metabolism; Colletotrichum - pathogenicity; Colletotrichum gloeosporioides; Conidia; Defects; Deletion mutant; Elongation; Fungal Proteins - genetics; Fungal Proteins - metabolism; Fungi; Gene Deletion; Gene expression; Gene regulation; Genes, Fungal; Guanosine triphosphatases; Homology; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Hyphae - metabolism; Integrity; Leaves; Life Sciences; Microbial Genetics and Genomics; Microbiology; Morphogenesis; Morphology; Mutation; Original Article; Pathogenicity; Pathogens; Plant Development; Plant Diseases - microbiology; Plant Sciences; Plants - microbiology; Polarity; Poplar; Proteomics; Reactive Oxygen Species - metabolism; Transcription; Virulence
• ISSN: 0172-8083; 1432-0983
• DOI: 10.1007/s00294-018-0833-9

The Rho GTPase Cdc42 is conserved in fungi and plays a key role in regulating polarity establishment, morphogenesis and differentiation. In this study, we identified an ortholog of Cdc42, CgCdc42 , and functionally characterized it to determine the role of Cdc42 in the development and pathogenicity of Colletotrichum gloeosporioides , a causal agent of poplar anthracnose. Targeted deletion of CgCdc42 resulted in reduced vegetative growth and dramatic morphological defects, including the formation of elongated conidia and abnormally shaped appressoria. Moreover, CgCdc42 deletion mutants were less virulent on poplar leaves than were wild type. Appressoria formed by Δ CgCdc42 mutants were morphologically abnormal and present in lower numbers on poplar leaves than were those formed by wild type. However, an ROS scavenging assay indicated that the Δ CgCdc42 mutants maintained wild type pathogenicity in the absence of ROS despite having fewer appressoria than wild type, suggesting that the Δ CgCdc42 mutants were deficient in their tolerance of ROS. Additionally, we also found that the distribution of ROS was different after the deletion of CgCdc42 , the Δ CgCdc42 mutants were hypersensitive to H 2 O 2 , and transcriptional analysis revealed that CgCdc42 is involved in the regulation of ROS-related genes. Furthermore, loss of CgCdc42 caused defects in cell wall integrity and an uneven distribution of chitin. These data collectively suggest that CgCdc42 plays an important role in the regulation of vegetative growth, morphological development, cell wall integrity and ROS-mediated plant infection in C. gloeosporioides .