The fungal metabolite 4-hydroxyphenylacetic acid from Neofusicoccum parvum modulates defence responses in grapevine.

In a consequence of global warming, grapevine trunk diseases (GTDs) have become a pertinent problem to viticulture, because endophytic fungi can turn necrotrophic upon host stress killing the plant. In Neofusicoccum parvum Bt-67, plant-derived ferulic acid makes the fungus release Fusicoccin aglycone triggering plant cell death. Now, we show that the absence of ferulic acid lets the fungus secrete 4-hydroxyphenylacetic acid (4-HPA), mimicking the effect of auxins on grapevine defence and facilitating fungal spread. Using Vitis suspension cells, we dissected the mode of action of 4-HPA during defence triggered by the bacterial cell-death elicitor, harpin. Early responses (cytoskeletal remodelling and calcium influx) are inhibited, as well as the expression of Stilbene Synthase 27 and phytoalexin accumulation. In contrast to other auxins, 4-HPA quells transcripts for the auxin conjugating GRETCHEN HAGEN 3. We suggest that 4-HPA is a key component of the endophytic phase of N. parvum Bt-67 preventing host cell death. Therefore, our study paves the way to understand how GTDs regulate their latent phase for successful colonisation, before turning necrotrophic and killing the vines. © 2023 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Citation

Noemi Flubacher, Raymonde Baltenweck, Philippe Hugueney, Jochen Fischer, Eckhard Thines, Michael Riemann, Peter Nick, Islam M Khattab. The fungal metabolite 4-hydroxyphenylacetic acid from Neofusicoccum parvum modulates defence responses in grapevine. Plant, cell & environment. 2023 Nov;46(11):3575-3591

PMID: 37431974

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