Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, Cologne, Germany.
PLoS Pathog. 2012;8(4):e1002643. doi: 10.1371/journal.ppat.1002643. Epub 2012 Apr 5.
Phytopathogens secrete effector proteins to manipulate their hosts for effective colonization. Hemibiotrophic fungi must maintain host viability during initial biotrophic growth and elicit host death for subsequent necrotrophic growth. To identify effectors mediating these opposing processes, we deeply sequenced the transcriptome of Colletotrichum higginsianum infecting Arabidopsis. Most effector genes are host-induced and expressed in consecutive waves associated with pathogenic transitions, indicating distinct effector suites are deployed at each stage. Using fluorescent protein tagging and transmission electron microscopy-immunogold labelling, we found effectors localised to stage-specific compartments at the host-pathogen interface. In particular, we show effectors are focally secreted from appressorial penetration pores before host invasion, revealing new levels of functional complexity for this fungal organ. Furthermore, we demonstrate that antagonistic effectors either induce or suppress plant cell death. Based on these results we conclude that hemibiotrophy in Colletotrichum is orchestrated through the coordinated expression of antagonistic effectors supporting either cell viability or cell death.
植物病原体分泌效应蛋白来操纵宿主，以实现有效的定植。半活体真菌在最初的活体生长阶段必须维持宿主的活力，并引发宿主死亡，以进行后续的坏死生长。为了鉴定介导这些相反过程的效应蛋白，我们对侵染拟南芥的炭疽菌进行了深度转录组测序。大多数效应基因是由宿主诱导的，并在与致病性转变相关的连续波中表达，表明在每个阶段都部署了不同的效应蛋白套件。通过荧光蛋白标记和透射电子显微镜-免疫金标记，我们发现效应蛋白定位于宿主-病原体界面的特定阶段的隔室中。特别是，我们发现效应蛋白从前驱体渗透孔中定点分泌，在宿主入侵之前，揭示了这个真菌器官新的功能复杂性。此外，我们还证明了拮抗效应蛋白可以诱导或抑制植物细胞死亡。基于这些结果，我们得出结论，炭疽菌的半活体特性是通过拮抗效应蛋白的协调表达来调控的，这些效应蛋白支持细胞活力或细胞死亡。
