Gachon Claire M M, Müller Dieter G, Strittmatter Martina, Murúa Pedro, Beckmann Max, Tsirigoti Amerssa, Wawra Stephan, Katsaros Christos, van West Pieter, Küpper Frithjof C
The Scottish Association for Marine Science, Scottish Marine Institute, Culture Collection for Algae and Protozoa, Oban, Argyll PA37 1QA, Scotland.
UMR 7245, Muséum National d'Histoire Naturelle - CNRS, CP 54, 57 rue Cuvier, 75005 Paris, France.
iScience. 2025 Jul 24;28(9):113195. doi: 10.1016/j.isci.2025.113195. eCollection 2025 Sep 19.
Brown algae (Phaeophyta) encompass key primary producers of temperate and cold coastal seas, such as kelps, the cultivation of which is rapidly expanding worldwide. Here, we show that across ten brown algal species, innate resistance against the intracellular oomycete pathogen is mediated by local cell death and accompanied by cell-wide deposition of β1-3 glucans and fluorescent metabolites, the accumulation of reactive oxygen species, and the expression of programmed cell death (PCD) markers. This response also occurs in compatible strains for a fraction of the infected algal cells, which makes it a quantitative trait. It is followed by the induction of two inducible autophagy-mediated defense responses already known for the oomycete pathogen . Overall, we unveil hypersensitive-like cell death as a conserved, core part of brown algal innate defenses, that is intertwined with a second line of inducible, autophagy-mediated defenses. These results open unprecedented avenues to elucidate the molecular mechanisms of pathogen recognition and disease resistance in brown algae.
褐藻（褐藻门）是温带和寒带沿海水域的关键初级生产者，例如海带，其养殖在全球范围内正在迅速扩张。在此，我们表明，在十种褐藻物种中，对细胞内卵菌病原体的先天抗性由局部细胞死亡介导，并伴随着全细胞范围内β1-3葡聚糖和荧光代谢物的沉积、活性氧的积累以及程序性细胞死亡（PCD）标记物的表达。这种反应在一部分受感染的藻类细胞的兼容菌株中也会发生，这使其成为一种数量性状。随后会诱导出两种已知的针对卵菌病原体的可诱导自噬介导的防御反应。总体而言，我们揭示了类过敏细胞死亡是褐藻先天防御的一个保守核心部分，它与第二条可诱导的、自噬介导的防御防线相互交织。这些结果为阐明褐藻中病原体识别和抗病性的分子机制开辟了前所未有的途径。
