The interactions between arbuscular mycorrhizal fungi (AMF) and non-host species are poorly studied. Particularly scarce is information on members of the Amaranthaceae/Chenopodiaceae family. Sugar beet (Beta vulgaris) plants were co-cultivated with a host species (Hordeum vulgare) in the presence (+AMF) or absence of Rhizophagus intraradices to explore the hypothesis that the presence of an active, pre-established AMF mycelium induces defense responses in the non-host species. Biomass of sugar beet did not respond to the +AMF treatment, while its root exudation of organic acids and phenolic acids was drastically decreased upon co-cultivation with +AMF barley. The most conspicuous effect was observed on a wide range of potential defense parameters being differentially influenced by the +AMF treatment in this non-host species. Antioxidant defense enzymes were activated and the level of endogenous jasmonic acid was elevated accompanied by nitric oxide accumulation and lignin deposition in the roots after long-term +AMF treatment. In contrast, significant reductions in the levels of endogenous salicylic acid and tissue concentration and exudation of phenolic acids indicated that AM fungus hyphae in the substrate did not induce a hypersensitive-type response in the sugar beet roots and downregulated certain chemical defenses. Our results imply that the fitness of this non-host species is not reduced when grown in the presence of an AMF mycelium because of balanced defense costs. Further studies should address the question of whether or not such modulation of defense pattern influences the pest resistance of sugar beet plants under field conditions.

中文翻译：

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大麦的丛枝菌根菌丝体在共培养下对非寄主甜菜的各种防御参数产生不同的影响。

丛枝菌根真菌（AMF）与非寄主物种之间的相互作用研究很少。关于the菜科/藜科的成员的信息尤其稀少。将甜菜（Beta vulgaris）植物与宿主物种（大麦（Hordeum vulgare））在存在（+ AMF）或不存在根瘤菌的情况下共培养，以探讨以下假设：存在活性的，预先建立的AMF菌丝体会诱导防御反应在非寄主物种中。甜菜的生物量对+ AMF处理无反应，而与+ AMF大麦共培养后，有机酸和酚酸的根系分泌物急剧减少。在该非寄主物种中，在+ AMF处理的不同影响下，对广泛的潜在防御参数产生了最明显的影响。长期+ AMF处理后，抗氧化防御酶被激活，内源性茉莉酸水平升高，同时一氧化氮积累和木质素在根部沉积。相反，内源性水杨酸的水平和组织浓度的显着降低以及酚酸的渗出表明底物中的AM真菌菌丝没有在甜菜根中诱导超敏型反应，并且下调了某些化学防御作用。我们的结果暗示，由于平衡的防御成本，当在AMF菌丝体存在下生长时，这种非寄主物种的适应性不会降低。进一步的研究应解决以下问题：防御模式的这种调节是否会影响田间条件下甜菜植物的抗虫性。