Journal of Integrative Agriculture ›› 2016, Vol. 15 ›› Issue (12): 2786-2794.DOI: 10.1016/S2095-3119(16)61472-7

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  • 收稿日期:2016-01-25 出版日期:2016-12-01 发布日期:2016-12-02

MAP kinase gene STK1 is required for hyphal, conidial, and appressorial development, toxin biosynthesis, pathogenicity, and hypertonic stress response in the plant pathogenic fungus Setosphaeria turcica

LI Po1, 2*, GONG Xiao-dong1*, JIA Hui1*, FAN Yong-shan1, 3, ZHANG Yun-feng1, 3, CAO Zhi-yan1, HAO Zhi-min1, HAN Jian-min1, GU Shou-qin1, 4, DONG Jin-gao   

  1. 1 Mycotoxin and Molecular Plant Pathology Laboratory, Agricultural University of Hebei, Baoding 071000, P.R.China
    2 Institute of Plant Protection, Hebei Academy of Agriculture and Forestry Sciences, Baoding 071000, P.R.China
    3 Tangshan Normal University, Tangshan 063000, P.R.China
  • Received:2016-01-25 Online:2016-12-01 Published:2016-12-02
  • Contact: GU Shou-qin, Tel: +86-312-7528142, E-mail: gushouqin@126.com; DONG Jin-gao, Tel: +86-312-7528266, E-mail: shmdjg@hebau.edu.cn
  • About author:LI Po, Tel: +86-312-7528142, E-mail: lipo-0524@163.com; GONG Xiao-dong, Tel: +86-312-7528142, E-mail: gxdjiy123@gmail.com; JIA Hui, Tel: +86-312-7528260, E-mail: shmjiahui@hebau.edu.cn;
  • Supported by:

    This study was supported by the National Natural Science Foundation of China (31171805 and 31371897).

Abstract: The mitogen-activated protein kinase (MAPK), a key signal transduction component in the MAPK cascade pathway, regulates a variety of physiological activities in eukaryotes.  However, little is known of the role MAPK plays in phytopathogenic fungi.  In this research, we cloned the MAPK gene STK1 from the northern corn leaf blight pathogen Setosphaeria turcica and found that the gene shared high homology with the high osmolality glycerol (HOG) MAPK gene HOG1 of Saccharomyces cerevisiae.  In addition, gene knockout technology was employed to investigate the function of STK1.  Gene knockout mutants (KOs) were found to have altered hyphae morphology and no conidiogenesis, though they did show similar radial growth rate compared to the wild-type strain (WT).  Furthermore, microscope observations indicated that STK1 KOs did not form normal appressoria at 48 h post-inoculation on a hydrophobic surface.  STK1 KOs had reduced virulence, a significantly altered Helminthosporium turcicum (HT)-toxin composition, and diminished pathogenicity on the leaves of susceptible inbred corn OH43.  Mycelium morphology appeared to be significantly swollen and the radial growth rates of STK1 KOs declined in comparison with WT under high osmotic stress.  These results suggested that STK1 affects the hyphae development, conidiogenesis, and pathogenicity of S. turcica by regulating appressorium development and HT-toxin biosynthesis.  Moreover, the gene appears to be involved in the hypertonic stress response in S. turcica.

Key words:  Setosphaeria turcica ,  MAPK ,  conidiogenesis ,  HT-toxin ,  pathogenicity