Systematic Characterization Of Homeobox Genes In Fusarium Graminearum

The Fusarium graminearum (teleomorph Gibberella zeae) is one of the main causal agents of Fusarium head blight (FHB) or scab, which causes the most destructive disease on wheat and barley throughout the world. In addition to yield losses, Fusarium graminearum produces some certain mycotoxins in infected crops leading to huge damages in both human and animals. However, it is rarely reported about the mechanisms concerning its development, sporulation, toxin production and pathogen invasion, especially in the case of regulatory machinery in molecular level. The Homeobox genes, as transcriptional factors, play a vital role in regulating the development and cellular differentiation in eukaryote. It is shown that there are13Homeobox genes according to the bioinformatic analysis in Fusarium graminearum. Among13genes deletion mutants generated respectively through homologue recombination strategy, Fghtf8deletion mutant displays dense colony with severe delayed in growth, as well as profuse braches of aerial hyphae in comparison with the wide type strain. While biomass, conidiation and pathogenecity of the deletion mutant remained unchanged. The complementation test indicated that the FgHTF8coding gene was not only able to recover its own knock-out mutant but also its homologue functional loss mutant in Magnaporthe oryzae. The Fghtf5deletion mutant showsed great compromising capacity of conidiation in conidiophore, but can produce conidia at the end of mycelia with normal infection on wheat. In the test of complementation, FgHTF5knock out mutant was recovered. The FgHTF8and FgHTF5double deletion mutant displayed severe delay in colony growth and remarkable reduction in conidiation, which implicated that both genes functioned independently in the regulation of colony growth and conidiation. The GFP localization test showed stable expression of protein during the time course for Oh,4h and8h in germination, and GFP signal over-laped with nucleus dyed by DAPI, which demonstrated that FgHtf13localize in nucleus, consistent with transcription factors’sub-cellular localization.