Shetty Nandini P, Mehrabi Rahim, Lütken Henrik, Haldrup Anna, Kema Gert H J, Collinge David B, Jørgensen Hans Jørgen Lyngs
University of Copenhagen, Faculty of Life Sciences, Department of Plant Biology, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
Plant Research International, Wageningen University and Research Centre, PO Box 16, 6700 AA Wageningen, the Netherlands.
New Phytol. 2007;174(3):637-647. doi: 10.1111/j.1469-8137.2007.02026.x.
Hydrogen peroxide (H(2)O(2)) is reported to inhibit biotrophic but benefit necrotrophic pathogens. Infection by necrotrophs can result in a massive accumulation of H(2)O(2) in hosts. Little is known of how pathogens with both growth types are affected (hemibiotrophs). The hemibiotroph, Septoria tritici, infecting wheat (Triticum aestivum) is inhibited by H(2)O(2) during the biotrophic phase, but a large H(2)O(2) accumulation occurs in the host during reproduction. Here, we infiltrated catalase, H(2)O(2) or water into wheat during the biotrophic or the necrotrophic phase of S. tritici and studied the effect of infection on host physiology to get an understanding of the survival strategy of the pathogen. H(2)O(2) removal by catalase at both early and late stages made plants more susceptible, whereas H(2)O(2) made them more resistant. H(2)O(2) is harmful to S. tritici throughout its life cycle, but it can be tolerated. The late accumulation of H(2)O(2) is unlikely to result from down-regulation of photosynthesis, but probably originates from damage to the peroxisomes during the general tissue collapse, which is accompanied by release of soluble sugars in a susceptible cultivar.
据报道，过氧化氢（H₂O₂）可抑制活体营养型病原体，但对死体营养型病原体有益。死体营养型病原体感染可导致宿主中大量积累H₂O₂。对于兼具两种生长类型的病原体（半活体营养型）受何影响知之甚少。感染小麦（Triticum aestivum）的半活体营养型病原体小麦叶枯病菌（Septoria tritici）在活体营养阶段受到H₂O₂抑制，但在繁殖期间宿主中会大量积累H₂O₂。在此，我们在小麦叶枯病菌的活体营养或死体营养阶段将过氧化氢酶、H₂O₂或水注入小麦，并研究感染对宿主生理的影响，以了解该病原体的生存策略。在早期和晚期通过过氧化氢酶去除H₂O₂会使植物更易感病，而H₂O₂则使其更具抗性。H₂O₂在小麦叶枯病菌的整个生命周期中都是有害的，但它可以被耐受。H₂O₂的后期积累不太可能是光合作用下调的结果，而可能源于在一般组织崩溃期间过氧化物酶体受到的损伤，这伴随着感病品种中可溶性糖的释放。
