Kim Hyeran, Kwon Hyeokjin, Kim Soohong, Kim Mi Kyung, Botella Miguel A, Yun Hye Sup, Kwon Chian
Max-Planck-Institut für Züchtungsforschung, Department of Plant Microbe Interactions, Carl-von-Linné-Weg 10, D-50829 Köln, Germany Center for Genome Engineering, Institute for Basic Science, Daejeon 305-811, Korea These authors contributed equally to this work.
Department of Molecular Biology, Dankook University, Yongin 448-701, Korea These authors contributed equally to this work.
Plant Cell Physiol. 2016 Jun;57(6):1133-41. doi: 10.1093/pcp/pcw061. Epub 2016 Mar 25.
PEN1, one of the plasma membrane (PM) syntaxins, comprises an immune exocytic pathway by forming the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex with SNAP33 and VAMP721/722 in plants. Although this secretory pathway is also involved in plant growth and development, how plants control their exocytic activity is as yet poorly understood. Since constitutive PEN1 cycling between the PM and endocytosed vesicles is critical for its immune activity, we studied here the relationship of PEN1 to synaptotagmin 1 (SYT1) that is known to regulate endocytosis at the PM. Interestingly, syt1 plants showed enhanced disease resistance to the Arabidopsis-adapted Golovinomyces orontii fungus, and elevated protein but not transcript levels of PEN1 Calcium-dependent promotion of PEN1-SYT1 interaction suggests that SYT1 controls defense activities of the PEN1-associated secretory pathway by post-translationally modulating PEN1. Increased PEN1-SYT1 interaction and inhibited PEN1 SNARE complex induction by G. orontii additionally suggest that the adaption of phytopathogens to host plants might partly result from effective suppression of the PEN1-related secretory pathway. Further genetic analyses revealed that SYT1 also regulates the atypical peroxisomal myrosinase PEN2-associated secretory pathway.
PEN1是一种质膜（PM） syntaxin蛋白，通过与植物中的SNAP33和VAMP721/722形成可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）复合体，构成一条免疫胞吐途径。尽管这条分泌途径也参与植物的生长和发育，但植物如何控制其胞吐活性目前仍知之甚少。由于PEN1在质膜和内吞小泡之间的组成型循环对其免疫活性至关重要，我们在此研究了PEN1与已知在质膜调节内吞作用的突触结合蛋白1（SYT1）之间的关系。有趣的是，syt1植物对适应拟南芥的白粉菌（Golovinomyces orontii）表现出增强的抗病性，并且PEN1的蛋白水平升高但转录本水平未升高。PEN1与SYT1相互作用的钙依赖性促进表明，SYT1通过翻译后调节PEN1来控制与PEN1相关的分泌途径的防御活性。白粉菌增加PEN1与SYT1的相互作用并抑制PEN1 SNARE复合体的诱导，这进一步表明植物病原体对宿主植物的适应性可能部分源于对PEN1相关分泌途径的有效抑制。进一步的遗传分析表明，SYT1还调节非典型过氧化物酶体黑芥子酶PEN2相关的分泌途径。
