Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2019
Publication Date: 3/17/2019
Citation: Brown, D.W., Kim, H.-S., Proctor, R. 2019. Oxylipins differentially impact Fusarium gene expression [abstract].
Technical Abstract: Oxylipins are low-molecular-weight metabolites that affect plant-fungal pathogen interactions and the production of mycotoxins and other secondary metabolites (SMs). Changes in maize oxylipin profiles can significantly affect mycotoxin production and development in fungi that infect maize. Seeds of a maize line in which the lipoxygenase LOX3 was inactivated repressed fumonisin production by Fusarium verticillioides and increased aflatoxin production by Aspergillus flavus. In contrast, seeds of the ZmLOX12 mutant were colonized more by F. verticillioides and led to more fumonisin synthesis. The cause(s) of these changes in mycotoxin production and susceptibility to infection are not known but are presumably mediated by changes in oxylipin content. Infection of the ZmLOX12 mutant led to less jasmonic acid (JA) synthesis and less JA biosynthetic gene transcription. To begin to determine how perturbation of oxylipin profiles regulate fumonisin production and colonization, we used RNA-seq to analyze changes in the transcriptome of F. verticillioides after exposure to the oxylipins 9-hydroperoxy-octadecadienoic acid (HpODE), 13-HpODE, 9-hydroxy-octadecadienoic acid (HODE) and 13-HODE. The results indicate that these metabolites differentially affect expression of hundreds of genes including multiple G-protein coupled receptor (GPCR) genes and the entire fumonisin gene cluster. In contrast, expression of the fusarin and fusaric acid gene clusters were not affected. Given the role of GPCRs in relaying environmental signals from the cell surface to transcriptional machinery in the nucleus, it is possible that some of these differentially expressed GPCRs and GPCR-like proteins are involved in the signaling pathway that allow oxylipins to affect SM gene expression in F. verticillioides.