The very long‐chain fatty acid elongase FgElo2 governs tebuconazole sensitivity and virulence in Fusarium graminearum

Abstract

Very long‐chain fatty acids (VLCFAs), the precursors for the synthesis of sphingolipids (SLs), play pivotal roles in the development and stress response in eukaryotes. In Saccharomyces cerevisiae, VLCFAs are synthesized in the endoplasmic reticulum (ER) through a four‐step elongation cycle. However, the functions of VLCFA elongases in phytopathogenic fungi remain largely unexplored. Here, we identified a single copy of the VLCFA elongase gene FgELO2 in Fusarium graminearum that causes Fusarium head blight worldwide. FgElo2 localized to ER membrane, and deletion mutant of FgELO2 exhibited serious defects in vegetative growth and conidiation. Importantly, ΔFgElo2 led to ergosterol content reduction and disrupted the ER‐localization of 14‐α‐demethylase FgCyp51s, indicating that the scarce of SLs reduced ergosterol, which ultimately elevated the sensitivity of ΔFgElo2 to tebuconazole. Fluorescent microscopic examination suggested that FgElo2 was degraded upon cell membrane stress. ΔFgElo2 showed decreased phosphorylation of high osmolarity glycerol (HOG) pathway and subsequently exhibited remarkable sensitivity to osmotic stress. In addition, fungal virulence was dramatically reduced in ΔFgElo2 via inhibiting deoxynivalenol production and formation of infection structures. Together, this study demonstrates that the VLCFA elongase FgElo2 modulates fungal development, tebuconazole sensitivity, stress responses and virulence, which may advance our understanding of pathogen–host interactions mediated by VLCFAs.

Low Molecular Weight and High Deacetylation Degree Chitosan Batch Alleviates Pathogenesis, Toxin Accumulation, and Fusarium Gene Regulation in Barley Leaf Pathosystem

“…The synthesis of fatty acids is important for vegetative growth and for the response to stress in eukaryotes. In Fg , deletion mutation of the ergosterol pathway gene (elongase gene; Fg ELO2 ) decreased fungi sensitivity to tebuconazole and also reduced virulence [ 40 ]. In the case of chitosan-treated Fg , we observed a strong up-regulation of genes connected directly with response to oxidative stress such as: catalase 1 (FGSG_06554), catalase 3 (FGSG_06733), catalase 4 (FGSG_12369) up-regulated, respectively, 6.32, 4.02 and 2.18 fold [ 41 ].…”

“…Similarly, the up-regulated expression of FGSG_0007 was consistent with the qPCR data, and the results confirmed the RNA-Seq approach to quantify the expression. Previously, several articles have used qPCR as an alternative to gene expression data to verify the authenticity of results [ 27 , 40 , 44 ].…”

A fatty acid elongase complex regulates cell membrane integrity and septin‐dependent host infection by the rice blast fungus

“…Our study identified VLCFA biosynthesis as another metabolic pathway crucial for host infection by M. oryzae . Due to the conservation of enzymes involved in VLCFA biosynthesis, it is very likely that this metabolic pathway is broadly important for pathogenesis of many other fungal pathogens such as F. graminearum (Wang, Chen, et al., 2022 ).…”

“…In plants, VLCFAs are imperative to programmed cell death during the abiotic stress response, cell elongation of cotton fibres, cell plate formation, cell proliferation in shoot apex and regeneration of callus (Bach et al., 2011 ; Du Granrut & Cacas, 2016 ; Haslam & Kunst, 2013 ; Liu et al., 2024 ; Luzarowska et al., 2023 ; Shang et al., 2016 ; Yang et al., 2023 ; Zheng et al., 2005 ). Increasing evidence has demonstrated the importance of VLCFAs for host infection by pathogens including M. oryzae (He et al., 2020 ), Fusarium graminearum (Wang, Chen, et al., 2022 ), protozoan parasite Toxoplasma gondii (Ramakrishnan et al., 2015 ) and human cytomegalovirus (Koyuncu et al., 2013 ). However, the biosynthesis and mechanistic role of VLCFAs remains poorly understood in microbial pathogens.…”