An RXLR effector PlAvh142 from Peronophythora litchii triggers plant cell death and contributes to virulence

摘要

Litchi downy blight, caused by the phytopathogenic oomycete , results in tremendous economic loss in litchi production every year To successfully colonize the host cell, species secret hundreds of RXLR effectors that interfere with plant immunity and facilitate the infection process. Previous work has already predicted 245 candidate RXLR effector‐encoding genes in , 212 of which have been cloned and tested for plant cell death‐inducing activity in this study. We found three such RXLR effectors could trigger plant cell death through transient expression in . Further experiments demonstrated that PlAvh142 could induce cell death and immune responses in several plants. We also found that PlAvh142 localized in both the cytoplasm and nucleus of plant cells. The cytoplasmic localization was critical for its cell death‐inducing activity. Moreover, deletion either of the two internal repeats in PlAvh142 abolished the cell death‐inducing activity. Virus‐induced gene silencing assays showed that cell death triggered by PlAvh142 was dependent on the plant transduction components (require for resistance), (suppressor of the G2 allele of ) and  (heat shock protein 90). Finally, knockout of resulted in significantly attenuated virulence on litchi plants, whereas the overexpressed mutants were more aggressive. These data indicated that PlAvh142 could be recognized in plant cytoplasm and is an important virulence RXLR effector of .