Identification of an Asexual Reproduction Inducer of Phytopathogenic and Toxigenic Fusarium

Abstract

Asexual and sexual reproduction are the most important biological events in the life cycle of phytopathogenic and toxigenic Fusarium and are responsible for disease epidemics.H owever,t he signaling molecules whichi nduce the asexual reproduction of Fusarium are unknown. Herein we describe the structure elucidation, including the absolute configuration, of Fusarium asexual reproduction inducer (FARI), an ew sesquiterpene derivative,b ys pectroscopic analysis,t otal synthesis,a nd conidium-inducing assays of synthetic isomers.W eh ave also uncovered the universality of FARI among Fusarium species.M oreover,amechanism-ofaction study suggested that the Gpmk1 and LaeA signaling pathwaysa re required for conidium formation induced by FARI;c onversely,t he Mgv1 of mitogen-activated protein kinase is not involved in conidium formation. FARI exhibited conidium-inducing activity at an extremely low dose and high stereoselectivity,w hichm ay suggest the presence of as tereospecific target.

DNA Methylation Is Responsive to the Environment and Regulates the Expression of Biosynthetic Gene Clusters, Metabolite Production, and Virulence in Fusarium graminearum

“…A total of 12 mass features (having positive loading in PC 1) were significantly enriched in the WT strain, including pigmented molecules such as aurofusarin, rubrofusarin, and fuscofusarin along with fusarins, fusaristatin A, and the metabolite FARI (Fusarium asexual reproduction inducer (Qi et al, 2018 ), also co-named as tricinolone (Adpressa et al, 2019 ). The differential pigment production was consistent with observed culture phenotypes (i.e., loss of pigment production in Δ FgDim2 /Δ FgRid strain compared to WT) as well as the RNA-Seq and RT-qPCR experiments that showed downregulation of a majority of the genes in the aurofusarin gene cluster in the double mutant strain ( Supplementary Data Sheet 3 ; Supplementary Figure 7 ).…”

“…Under NPN conditions, both WT and Δ FgDim-2 /Δ FgRid mutant strains were observed to produce trichothecenes, fusaoctaxins, and gramillins and by day 14, growth of the WT strain progressed into advanced stressed conditions, conducive to produce conidia that coincided with the production of the molecule FARI (Fusarium Asexual Reproduction Inducer—a universal regulator for asexual spore formation in Fusarium ) (Qi et al, 2018 ) and pigment molecules such as aurofusarin, fucofusarin, and rubrofusarin. FARI is a stereospecific signaling molecule that initiates a signaling cascade involved with Gpmk1 MAPK and Fg LaeA- Fg VeA velvet pathways (Qi et al, 2018 ). The Fg LaeA carries a conserved methyltransferase domain and is proposed to play a role in chromatin-based regulation of asexual development (in the dark) in F. graminearum , along with secondary metabolism and regulatory pathways essential for disease development in wheat (Kim et al, 2013 ).…”