Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China.
Int J Mol Sci. 2019 Aug 1;20(15):3770. doi: 10.3390/ijms20153770.
Autophagy is a well-defined catabolic mechanism whereby cytoplasmic materials are engulfed into a structure termed the autophagosome. Methyl jasmonate (MeJA), a plant hormone, mediates diverse developmental process and defense responses which induce a variety of metabolites. In plants, little is known about autophagy-mediated responses against MeJA. In this study, we used high-throughput comparative proteomics to identify proteins of latex in the laticifers. The isobaric tags for relative and absolute quantification (iTRAQ) MS/MS proteomics were performed, and 298 proteins among MeJA treated groups and the control group of Euphorbia kansui were identified. It is interesting to note that 29 significant differentially expressed proteins were identified and their associations with autophagy and ROS pathway were verified for several selected proteins as follows: α-L-fucosidase, β-galactosidase, cysteine proteinase, and Cu/Zn superoxide dismutase. Quantitative real-time PCR analysis of the selected genes confirmed the fact that MeJA might enhance the expression of some genes related to autophagy. The western blotting and immunofluorescence results of ATG8 and ATG18a which are two important proteins for the formation of autophagosomes also demonstrated that MeJA could promote autophagy at the protein level. Using the electron microscope, we observed an increase in autophagosomes after MeJA treatment. These results indicated that MeJA might promote autophagy in E. kansui laticifers; and it was speculated that MeJA mediated autophagy through two possible ways: the increase of ROS induces ATG8 accumulation and then aotophagosome formation, and MeJA promotes ATG18 accumulation and then autophagosome formation. Taken together, our results provide several novel insights for understanding the mechanism between autophagy and MeJA treatment. However, the specific mechanism remains to be further studied in the future.
自噬是一种明确的分解代谢机制，其中细胞质物质被吞噬到称为自噬体的结构中。茉莉酸甲酯（MeJA）是一种植物激素，介导多种发育过程和防御反应，诱导多种代谢物。在植物中，对自噬介导的对 MeJA 的反应知之甚少。在这项研究中，我们使用高通量比较蛋白质组学来鉴定乳管中的乳胶蛋白质。进行了等重标记相对和绝对定量（iTRAQ）MS/MS 蛋白质组学分析，鉴定了 MeJA 处理组和对照的Euphorbia kansui 中的 298 种蛋白质。有趣的是，鉴定出 29 种显着差异表达的蛋白质，并验证了它们与自噬和 ROS 途径的关联，选择了几种选定的蛋白质如下：α-L-岩藻糖苷酶，β-半乳糖苷酶，半胱氨酸蛋白酶和 Cu/Zn 超氧化物歧化酶。所选基因的定量实时 PCR 分析证实了 MeJA 可能增强与自噬相关的某些基因表达的事实。自噬体形成的两个重要蛋白质 ATG8 和 ATG18a 的 Western 印迹和免疫荧光结果也表明 MeJA 可以在蛋白质水平上促进自噬。使用电子显微镜，我们观察到 MeJA 处理后自噬体增加。这些结果表明，MeJA 可能促进 E. kansui 乳管中的自噬；并且推测 MeJA 通过两种可能的方式介导自噬：ROS 的增加诱导 ATG8 积累，然后形成自噬体，MeJA 促进 ATG18 积累，然后形成自噬体。总之，我们的结果为理解自噬与 MeJA 处理之间的机制提供了一些新的见解。然而，具体的机制仍有待进一步研究。
