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BioMed Research International
Volume 2016, Article ID 7496569, 11 pages
http://dx.doi.org/10.1155/2016/7496569
Research Article

ChSte7 Is Required for Vegetative Growth and Various Plant Infection Processes in Colletotrichum higginsianum

The Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, Hubei 430070, China

Received 29 March 2016; Revised 19 May 2016; Accepted 30 June 2016

Academic Editor: Guo-Tian Li

Copyright © 2016 Qinfeng Yuan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Colletotrichum higginsianum is an important hemibiotrophic phytopathogen that causes crucifer anthracnose in various regions of the world. In many plant-pathogenic fungi, the Ste11-Ste7-Fus3/Kss1 kinase pathway is essential to pathogenicity and various plant infection processes. To date, the role of ChSte7 in C. higginsianum encoding a MEK orthologue of Ste7 in Saccharomyces cerevisiae has not been elucidated. In this report, we investigated the function of ChSte7 in the pathogen. The ChSte7 is predicted to encode a 522-amino-acid protein with a S_TKc conserved domain that shares 44% identity with Ste7 in S. cerevisiae. ChSte7 disruption mutants showed white colonies with irregularly shaped edges and extremely decreased growth rates and biomass productions. The ChSte7 disruption mutants did not form appressoria and showed defects in pathogenicity on leaves of Arabidopsis thaliana. When inoculated onto wounded leaf tissues, the ChSte7 disruption mutants grew only on the surface of host tissues but failed to cause lesions beyond the wound site. In contrast, both the wild-type and complementation strains showed normal morphology, produced appressoria, and caused necrosis on leaves of Arabidopsis. Analysis with qRT-PCR suggested that ChSte7 was highly expressed during the late stages of infection. Taken together, our results demonstrate that ChSte7 is involved in regulation of vegetative growth, appressorial formation of C. higginsianum, and postinvasive growth in host tissues.