今天，介绍的是新发表在《Plant Cell》上的研究论文，由北京林业大学林金星团队发表的论文《Secretion of Phospholipase Dδ Functions as a Regulatory Mechanism in Plant Innate Immunity》。
植物磷脂酶Ds（PLDs），磷脂信号传导的重要调节剂，在多个信号转导级联反应中起作用；然而，调节PLDs响应病原体的机制仍不清楚。在本文中，作者发现在大麦白粉病真菌Blumeria graminis f. sp. hordei (Bgh)的进入位点的细胞中，拟南芥PLDs大量积累。
使用光漂白后的荧光恢复（FRAP）和单分子分析，观察到几丁质处理后质膜的PLD密度更高；PLD也经历了快速胞吐作用。利用荧光寿命成像显微镜（FRET-FLIM）进行的荧光共振能量转移表明，PLD和微域标记蛋白AtREMORIN 1.3（AtREM 1.3）之间的相互作用随着几丁质的增加而增加，表明病原体刺激后，胞吐作用有助于将PLD快速有效地分类到病原体侵染的微区中。
作者进一步揭示了在不同条件下，布雷菲德菌素A（BFA）的耐药途径与PLD分泌的敏感途径之间的平衡。在病原体攻击后，PLD分泌涉及对BFA敏感的PEN1相关的VAMP721 / 722介导的胞吐作用。分析磷脂酸（PA），H2O2和茉莉酸（JA）的水平以及相关基因的表达表明，PLD的重新定位对于其活化产生PA并启动ROS和JA信号通路至关重要。
作者的发现表明，胞吐作用调节PLD的转运，从而在植物固有免疫中触发PA介导的信号传导。
Plant phospholipase Ds (PLDs), essential regulators of phospholipid signaling, function in multiple signal transduction cascades; however, the mechanisms regulating PLDs in response to pathogens remain unclear. Here, we found that Arabidopsis thaliana PLDδ accumulated in cells at the entry sites of the barley powdery mildew fungus, Blumeria graminis f. sp. hordei (Bgh). Using fluorescence recovery after photobleaching (FRAP) and single-molecule analysis, we observed higher PLDδ density in the plasma membrane after chitin treatment; PLDδ also underwent rapid exocytosis. Fluorescence resonance energy transfer with fluorescence lifetime imaging microscopy (FRET-FLIM) showed that the interaction between PLDδ and the microdomain marker AtREMORIN 1.3 (AtREM 1.3) increased in response to chitin, indicating that exocytosis facilitates rapid, efficient sorting of PLDδ into microdomains upon pathogen stimulus. We further unveiled a tradeoff between Brefeldin A (BFA)-resistant and sensitive pathways in secretion of PLDδ under diverse conditions. Upon pathogen attack, PLDδ secretion involved PEN1-associated VAMP721/722-mediated exocytosis sensitive to BFA. Analysis of phosphatidic acid (PA), H2O2 and jasmonic acid (JA) levels, and expression of related genes indicated that the relocalization of PLDδ is crucial for its activation to produce PA and initiate ROS and JA signaling pathways. Together, our findings revealed that the translocation of PLDδ to papillae is modulated by exocytosis, thus triggering PA-mediated signaling in plant innate immunity.
点击阅读原文，可以查看原文。
"植物病毒与抗逆研究"由浙江大学植物病理学博士研究生黑暗大邪神管理与运营。
欢迎读者交流投稿与合作，恳请读者多多宣传。
投稿、转载、信息发布与合作事宜，请联系xy_wu@
