Soil Science Department, Agriculture College, Isfahan University of Technology, Isfahan, Iran.
Jean-Pierre Bourgin Institute, INRA-Agro Paris Tech, Univ. Paris-Saclay, Versailles, France.
J Plant Physiol. 2020 Mar-Apr;246-247:153129. doi: 10.1016/j.jplph.2020.153129. Epub 2020 Jan 30.
Micronutrients provide a potentially interesting alternative to fungicides for the protection of crops against fungal pathogens. Here we studied the effect of foliar-applied manganese (Mn) in the form of MnSO on severity of anthracnose disease, caused by Colletotrichum lagenarium in cucumber (Cucumis sativus L.) plant. The study was done aimed to characterize the optimum dose and application time of Mn fertilizer on disease suppression as well as to identify the defense mechanisms by which Mn-treated plants resist to fungal disease. In preliminary tests, Mn was applied at different concentrations (1.8, 4.5 and 7.2 mM) and various time points (three days before or two hours before inoculation, or three days after inoculation). Results showed that application of Mn either before or after inoculation suppressed the fungal infection in leaves and cotyledons, with a higher efficiency when applied three days prior to inoculation. However, all applied concentrations of Mn equally reduced the disease severity. Mn treatment in the absence of the pathogen promoted lignification and reactive oxygen species (ROS) accumulation. Also, pre-inoculation Mn treatment enhanced pathogen-induced lignification, callose or ROS production and reduced pathogen-induced cell death. The increase of lignin, callose and ROS induction by Mn application were 34, 30 and 31 % compared to control, respectively. Together, the results suggested the effectiveness of Mn treatments on anthracnose alleviation in cucumber plants. The findings here have a practical importance in plant physiology studies to identify the resistance-relevant mechanisms to pathogens and in sustainable agriculture to control the fungal diseases by a safe method.
微量营养素为保护作物免受真菌病原体侵害提供了一种有潜力的替代杀菌剂的方法。在这里，我们研究了叶面喷施硫酸锰（MnSO）形式的锰对黄瓜（Cucumis sativus L.）炭疽病严重程度的影响，炭疽病由胶孢炭疽菌引起。这项研究旨在确定最佳施锰剂量和施用时间，以抑制病害，并确定锰处理植物抵抗真菌病害的防御机制。在初步试验中，Mn 以不同浓度（1.8、4.5 和 7.2 mM）和不同时间点（接种前三天或两小时，或接种后三天）施用。结果表明，接种前或接种后施用 Mn 均可抑制叶片和子叶中的真菌感染，在接种前三天施用效果更高。然而，所有施用浓度的 Mn 均可同等程度地降低病害严重程度。在没有病原体的情况下，Mn 处理会促进木质化和活性氧（ROS）积累。此外，接种前 Mn 处理增强了病原体诱导的木质化、胼胝质或 ROS 产生，并减少了病原体诱导的细胞死亡。与对照相比，Mn 处理分别使木质素、胼胝质和 ROS 诱导增加了 34%、30%和 31%。综上所述，Mn 处理对减轻黄瓜炭疽病具有有效性。这些发现对植物生理学研究具有实际意义，可以识别与病原体抗性相关的机制，在可持续农业中可以通过安全的方法来控制真菌病害。
