RXLR effectors: Master Modulators, Modifiers and Manipulators

Shumei Wang, Hazel McLellan, Petra C. Boevink, Paul R. J. Birch (Lead / Corresponding author)

Research output: Contribution to journalReview articlepeer-review


Cytoplasmic effectors with an Arg-any amino acid-Arg-Leu (RxLR) motif are encoded by hundreds of genes within the genomes of oomycete Phytophthora spp. and downy mildew pathogens. There has been a dramatic increase in our understanding of the evolution, function, and recognition of these effectors. Host proteins with a wide range of subcellular localizations and functions are targeted by RxLR effectors. Many processes are manipulated, including transcription, post-translational modifications, such as phosphorylation and ubiquitination, secretion, and intracellular trafficking. This involves an array of RxLR effector modes-of-action, including stabilization or destabilization of protein targets, altering or disrupting protein complexes, inhibition or utility of target enzyme activities, and changing the location of protein targets. Interestingly, approximately 50% of identified host proteins targeted by RxLR effectors are negative regulators of immunity. Avirulence RxLR effectors may be directly or indirectly detected by nucleotide-binding leucine-rich repeat resistance (NLR) proteins. Direct recognition by a single NLR of RxLR effector orthologues conserved across multiple Phytophthora pathogens may provide wide protection of diverse crops. Failure of RxLR effectors to interact with or appropriately manipulate target proteins in nonhost plants has been shown to restrict host range. This knowledge can potentially be exploited to alter host targets to prevent effector interaction, providing a barrier to host infection. Finally, recent evidence suggests that RxLR effectors, like cytoplasmic effectors from fungal pathogen Magnaporthe oryzae, may enter host cells via clathrin-mediated endocytosis.

Original languageEnglish
Pages (from-to)754-763
Number of pages10
JournalMolecular Plant - Microbe Interactions
Issue number12
Early online date26 Sept 2023
Publication statusPublished - Dec 2023


  • effector-triggered susceptibility
  • susceptibility factor
  • RxLR and EER motifs
  • effector targets
  • oomycete


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