New Study Elucidates Overall Infection Strategies of Phytopathogen Fusarium Graminearum inside Wheat Coleoptiles through in Planta Stage-Specific Gene Profiling

The filamentous fungus Fusarium graminearum (sexual stage Gibberella zeae) is the casual agent of several crop diseases including wheat Fusarium head blight (FHB) and maize Gibberella stalk rot. In addition, it produces mycotoxins (e.g. DON, deoxynivalenol) which poses a significant threaten to human and animal health. The F. graminearum genome encodes about 14,000 genes, more than a hundred of which were proved to be required for virulence. However, a complete blueprint for pathogenesis is still lacking. Recently researchers from Chinese Academy of Sciences revealed the overall infection strategies of phytopathogen Fusarium Graminearum inside wheat coleoptiles through in planta stage-specific gene profiling.

F. graminearum can proliferate both inside host and in vitro cultured medium. The differences between in planta and in vitro growing transcriptomes can aid in understanding the molecular mechanisms of F. graminearum pathogenicity. However, conventional methods hinder to obtain high-resolution transcriptome of pathogen inside host.

Researchers led by TANG Wei-Hua, professor of the Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, CAS, carefully isolated F. graminearum from inside wheat coleoptiles at 16, 40, and 64 hours after inoculation using laser capture microdissection, and then performed fungal microarray analysis. Global expression profiles of in planta–grown and in vitro–grown F. graminearum were compared to elucidate overall infection strategies: stage-dependent deployment of plant cell wall degrading enzymes; early mitigation and later production of reactive oxygen species; later onset of potentially phytotoxic secondary metabolite production.

The role in pathogenesis for several individual genes in the above categories was further validated by targeted gene disruption and quantitative bioassay for virulence. The insights in infection strategies of F. graminearum might contribute to develop prevention strategies against FHB in the future.

The experiments were performed by Xiao-Wei Zhang, Lei-Jie Jia, Yan Zhang and Gang Jiang, who are PhD candidate students in Dr. Tang’s group. Professor Xuan Li in the Institute of Plant Physiology and Ecology and Associate professor Dong Zhang contributed in statistical analysis of microarray data.

This study entitled “In planta stage-specific fungal gene profiling elucidates the molecular strategies of Fusarium graminearum growing inside wheat coleoptiles” was published online in The Plant Cell on December 24th, 2012. This work was supported by National Basic Research Program of China, the Chinese Academy of Sciences Knowledge Innovation Program, and the Ministry of Agriculture.

Link：http://www.plantcell.org/content/early/2012/12/24/tpc.112.105957.abstract

Author Contact:
TANG Wei-Hua, Principal Investigator
National Key Laboratory of Plant Molecular Genetics,
Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences,
Chinese Academy of Sciences,
Shanghai 200032, China.
Tel: 86-21-54924072
Fax: 86-21-5494015
Email: whtang@sibs.ac.cn