Institute for Dehesa Research (INDEHESA), Ingeniería Forestal y del Medio Natural, Universidad de Extremadura, Avenida Virgen del Puerto 2, 10600, Plasencia, Spain.
Escuela Técnica Superior de Ingeniería Agronómica y de Montes, Universidad de Córdoba, Carretera Nacional IV Km 396, 14014, Córdoba, Spain.
J Plant Physiol. 2019 Oct;241:153030. doi: 10.1016/j.jplph.2019.153030. Epub 2019 Aug 26.
Phytophthora cinnamomi (Pc) is a dangerous pathogen that causes root rot (ink disease) and threatens the production of chestnuts worldwide. Despite all the advances recently reported at molecular and physiological level, there are still gaps of knowledge that would help to unveil the defence mechanisms behind plant-Pc interactions. Bearing this in mind we quantified constitutive and Pc-induced stress-related signals (hormones and metabolites) complemented with changes in photosynthetic related parameters by exploring susceptible and resistant Castanea spp.-Pc interactions. In a greenhouse experiment, five days before and nine days after inoculation with Pc, leaves and fine roots from susceptible C. sativa and resistant C. sativa × C. crenata clonal 2-year-old plantlets were sampled (clones Cs14 and 111-1, respectively). In the resistant clone, stomatal conductance (g) and net photosynthesis (A) decreased significantly and soluble sugars in leaves increased, while in the susceptible clone g and A remained unchanged and proline levels in leaves increased. In the resistant clone, higher constitutive content of root SA and foliar ABA, JA and JA-Ile as compared to the susceptible clone were observed. Total phenolics and condensed tannins were highest in roots of the susceptible clone. In response to infection, a dynamic hormonal response in the resistant clone was observed, consisting of accumulation of JA, JA-Ile and ABA in roots and depletion of total phenolics in leaves. However, in the susceptible clone only JA diminished in leaves and increased in roots. Constitutive and Pc-induced levels of JA-Ile were only detectable in the resistant clone. From the hormonal profiles obtained in leaves and roots before and after infection, it is concluded that the lack of effective hormonal changes in C. sativa explains the lack of defence responses to Pc of this susceptible species.
樟疫霉（Pc）是一种危险的病原体，可导致根腐（墨水病），并威胁着全球栗树的生产。尽管最近在分子和生理水平上报告了所有进展，但仍存在知识空白，这些空白将有助于揭示植物与 Pc 相互作用背后的防御机制。考虑到这一点，我们通过探索易感和抗性栗属物种-Pc 相互作用，量化了组成性和 Pc 诱导的应激相关信号（激素和代谢物），并补充了与光合作用相关参数的变化。在温室实验中，在 Pc 接种前五天和接种后九天，从易感 C. sativa 和抗性 C. sativa×C. crenata 克隆 2 年生植株的叶片和细根中取样（克隆 Cs14 和 111-1，分别）。在抗性克隆中，气孔导度（g）和净光合作用（A）显著下降，叶片中可溶性糖增加，而在易感克隆中 g 和 A 保持不变，叶片中脯氨酸水平增加。在抗性克隆中，与易感克隆相比，根系中 SA 和叶片中 ABA、JA 和 JA-Ile 的组成性含量较高。易感克隆的根系中总酚和缩合单宁含量最高。在抗性克隆中，观察到对感染的动态激素反应，包括 JA、JA-Ile 和 ABA 在根部的积累和叶片中总酚的耗尽。然而，在易感克隆中，只有 JA 在叶片中减少，在根部中增加。在抗性克隆中仅可检测到组成性和 Pc 诱导的 JA-Ile 水平。从感染前后叶片和根系中获得的激素谱得出结论，C. sativa 中缺乏有效的激素变化解释了该易感物种对 Pc 缺乏防御反应的原因。
