In Normandy, flax is a plant of important economic interest because of its fibres. Fusarium oxysporum, a telluric fungus, is responsible for the major losses in crop yield and fibre quality. Several methods are currently used to limit the use of phytochemicals on crops. One of them is the use of plant growth promoting rhizobacteria (PGPR) occurring naturally in the rhizosphere. PGPR are known to act as local antagonists to soil‐borne pathogens and to enhance plant resistance by eliciting the induced systemic resistance (ISR). In this study, we first investigated the cell wall modifications occurring in roots and stems after inoculation with the fungus in two flax varieties. First, we showed that both varieties displayed different cell wall organization and that rapid modifications occurred in roots and stems after inoculation. Then, we demonstrated the efficiency of a Bacillus subtilis strain to limit Fusarium wilt on both varieties with a better efficiency for one of them. Finally, thermo‐gravimetry was used to highlight that B. subtilis induced modifications of the stem properties, supporting a reinforcement of the cell walls. Our findings suggest that the efficiency and the mode of action of the PGPR B. subtilis is likely to be flax variety dependent.

中文翻译：

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枯草芽孢杆菌菌株对亚麻对尖孢镰刀菌的保护作用及其对根和干细胞壁的影响。

在诺曼底，亚麻因其纤维而成为具有重要经济意义的植物。尖孢镰刀菌，一种碲化真菌，是造成农作物产量和纤维质量的主要损失。当前使用几种方法来限制在作物上使用植物化学物质。其中之一是利用根际中天然存在的促进植物生长的根际细菌（PGPR）。已知PGPR可以作为土壤传播病原体的局部拮抗剂，并通过引起诱导的系统抗性（ISR）来增强植物的抗性。在这项研究中，我们首先研究了在两种亚麻品种中接种真菌后在根和茎中发生的细胞壁修饰。首先，我们表明两种变种都显示出不同的细胞壁组织，并且接种后根和茎发生了快速修饰。然后，我们证明了枯草芽孢杆菌菌株能够有效限制镰刀菌在两个品种上都枯萎，其中之一变好。最后，用热重分析法强调了枯草芽孢杆菌可引起茎特性的改变，从而增强了细胞壁。我们的发现表明，PGPR枯草芽孢杆菌的效率和作用方式可能取决于亚麻品种。