Abstract Non-host resistance (NHR) describes the immunity state of plant species against non-adapted pathogen species and has been considered the most durable and effective form of plant resistance in nature. The objective of this work was to study the non-host resistance mechanisms involved in Arabidopsis thaliana and Malus domestica against Colletotrichum fructicola and Colletotrichum higginsianum, respectively. For this, the development of preinfective structures of Colletotrichum species, hypersensitivity responses and callose accumulation were monitored in host and non-host plants. Conidial germination and appressorial formation of Colletotrichum were affected on non-host leaf surfaces. Conidial germination and appressorial melanization of both Colletotrichum species occurred in a faster manner on arabidopsis than on apple leaves. On apple leaves, appressoria of C. higginsianum became more pedicelate, while on its host (arabidopsis) they were typically sessile. Hypersensitive response (HR) and appressorium-associated HR occurred at low frequency in epidermal cells of both plants, and no relationship could be established with NHR. Callose accumulation was significantly higher in inoculated non-host plants, mainly at attempted entry sites of Colletotrichum. Our results demonstrate that the mechanisms of NHR involved in this heterologous interaction were associated to pre-invasive events as demonstrated by the changes in development of preinfective structures and the accumulation of papillary callose at sites of penetration attempts.

中文翻译：

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拟南芥和苹果的非寄主抗性与炭疽菌属的胼胝质积累和感染前结构变化有关

摘要 非寄主抗性（NHR）描述了植物物种对非适应病原体物种的免疫状态，被认为是自然界中最持久、最有效的植物抗性形式。这项工作的目的是研究拟南芥和海棠分别对果炭黑炭疽菌和希金丝炭疽菌的非寄主抗性机制。为此，在寄主和非寄主植物中监测炭疽菌属感染前结构的发展、超敏反应和胼胝质积累。炭疽菌的分生孢子萌发和附着物形成在非寄主叶表面受到影响。两种炭疽病菌的分生孢子萌发和贴壁黑化在拟南芥上比在苹果叶上发生得更快。在苹果叶子上，C. higginsianum 的附着胞变得更加有蒂，而在其寄主（拟南芥）上，它们通常是无柄的。在两种植物的表皮细胞中，超敏反应 (HR) 和附着胞相关 HR 发生频率较低，并且与 NHR 没有关系。在接种的非寄主植物中，胼胝质积累显着更高，主要是在炭疽菌的尝试进入部位。我们的结果表明，NHR 参与这种异源相互作用的机制与侵入前事件相关，如感染前结构发展的变化和渗透尝试部位乳头状胼胝质的积累所证明的。在两种植物的表皮细胞中，超敏反应 (HR) 和附着胞相关 HR 发生频率较低，并且与 NHR 没有关系。在接种的非寄主植物中，胼胝质积累显着更高，主要是在炭疽菌的尝试进入部位。我们的结果表明，NHR 参与这种异源相互作用的机制与侵入前事件相关，如感染前结构发展的变化和渗透尝试部位乳头状胼胝质的积累所证明的。在两种植物的表皮细胞中，超敏反应 (HR) 和附着胞相关 HR 发生频率较低，并且与 NHR 没有关系。在接种的非寄主植物中，胼胝质积累显着更高，主要是在炭疽菌的尝试进入部位。我们的结果表明，NHR 参与这种异源相互作用的机制与侵入前事件相关，如感染前结构发展的变化和渗透尝试部位乳头状胼胝质的积累所证明的。