Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
Phytopathology. 2022 Jun;112(6):1335-1344. doi: 10.1094/PHYTO-11-21-0489-R. Epub 2022 Apr 27.
Pear is an important fruit tree worldwide, but it is often infected by the pathogen , which causes pear ring rot disease. To explore the effect of exogenous melatonin on the disease resistance of pear, we treated inoculated pear fruits with different concentrations of melatonin. The results showed that 100 μΜ of melatonin had the most significant effect with resistance to In addition, melatonin treatment significantly reduced the diameter of disease lesions and enhanced the endogenous melatonin content in pears inoculated with . Compared with the control treatment, melatonin treatment suppressed increases in reactive oxygen species (ROS) and activated ROS-scavenging enzymes. Treatment with exogenous melatonin maintained ascorbic acid-glutathione at more reductive status. The expression levels of core autophagic genes and autophagosome formation were elevated by melatonin treatment in pear fruits. Silencing of in conferred sensitivity to inoculation that was only slightly attenuated by melatonin treatment. After inoculation with , exogenous melatonin treatment led to higher levels of soluble sugars and organic acids in pear fruits than HO treatment. Overall, our results demonstrate that melatonin enhances resistance to by increasing autophagic activity and soluble sugar/organic acid accumulation.
梨是世界范围内重要的果树，但它经常受到病原体的感染，导致梨轮纹病。为了探索外源褪黑素对梨抗病性的影响，我们用不同浓度的褪黑素处理接种的梨果实。结果表明，100μM 的褪黑素效果最显著，可提高梨对 的抗性。此外，褪黑素处理显著降低了病斑的直径，并增强了接种 后的梨内源褪黑素含量。与对照处理相比，褪黑素处理抑制了活性氧（ROS）的增加，并激活了 ROS 清除酶。外源褪黑素处理使抗坏血酸-谷胱甘肽保持在更还原的状态。褪黑素处理可提高梨果实中核心自噬基因的表达水平并促进自噬体的形成。在 沉默后，接种导致对 的敏感性增加，而褪黑素处理的缓解作用很小。接种 后，外源褪黑素处理导致梨果实中可溶性糖和有机酸的含量高于 HO 处理。总之，我们的结果表明，褪黑素通过增加自噬活性和可溶性糖/有机酸积累来增强对 的抗性。
