The Fusarium oxysporum Avr2-Six5 Effector Pair Alters Plasmodesmatal Exclusion Selectivity to Facilitate Cell-to-Cell Movement of Avr2  

作　　者：Lingxue Cao Mila C. Blekemolen Nico Tintor Ben J.C. Cornelissen Frank L.W. Takken 

机构地区：[1]Molecular Plant Pathology, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, the Netherlands

出　　处：《Molecular Plant》2018年第5期691-705,共15页分子植物（英文版）

摘　　要：Pathogens use effector proteins to manipulate their hosts. During infection of tomato, the fungus Fusarium oxysporum secretes the effectors Avr2 and Six5. Whereas Avr2 suffices to trigger I-2-mediated cell death in heterologous systems, both effectors are required for I-2-mediated disease resistance in tomato. How Six5 participates in triggering resistance is unknown. Using bimolecular fluorescence complementation assays we found that Avr2 and Six5 interact at plasmodesmata. Single-cell transformation revealed that a 2xRFP marker protein and Avr2-GFP only move to neighboring cells in the presence of Six5. Six5 alone does not alter plasmodesmatal transduction as 2xRFP was only translocated in the presence of both effectors. In SIX5-expressing transgenic plants, the distribution of virally expressed Avr2-GFP, and subsequent onset of I-2-mediated cell death, differed from that in wild-type tomato. Taken together, our data show that in the presence of Six5, Avr2 moves from cell to cell, which in susceptible plants contributes to virulence, but in I-2 containing plants induces resistance.Pathogens use effector proteins to manipulate their hosts. During infection of tomato, the fungus Fusarium oxysporum secretes the effectors Avr2 and Six5. Whereas Avr2 suffices to trigger I-2-mediated cell death in heterologous systems, both effectors are required for I-2-mediated disease resistance in tomato. How Six5 participates in triggering resistance is unknown. Using bimolecular fluorescence complementation assays we found that Avr2 and Six5 interact at plasmodesmata. Single-cell transformation revealed that a 2xRFP marker protein and Avr2-GFP only move to neighboring cells in the presence of Six5. Six5 alone does not alter plasmodesmatal transduction as 2xRFP was only translocated in the presence of both effectors. In SIX5-expressing transgenic plants, the distribution of virally expressed Avr2-GFP, and subsequent onset of I-2-mediated cell death, differed from that in wild-type tomato. Taken together, our data show that in the presence of Six5, Avr2 moves from cell to cell, which in susceptible plants contributes to virulence, but in I-2 containing plants induces resistance.

关 键 词：PLASMODESMATA immunity EFFECTOR PATHOGEN FUSARIUM disease 

分 类 号：S823.4[农业科学—畜牧学] TS261.17[农业科学—畜牧兽医]