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Review
. 2024 May 10:15:1400659.
doi: 10.3389/fpls.2024.1400659. eCollection 2024.

Greater than the sum of their parts: an overview of the AvrRps4 effector family

Katie N Horton  1 , Walter Gassmann  1
Affiliations
Review

Greater than the sum of their parts: an overview of the AvrRps4 effector family

Katie N Horton et al. Front Plant Sci. .

Abstract

Phytopathogenic microbes use secreted effector proteins to increase their virulence in planta. If these effectors or the results of their activity are detected by the plant cell, the plant will mount an immune response which applies evolutionary pressure by reducing growth and success of the pathogen. Bacterial effector proteins in the AvrRps4 family (AvrRps4, HopK1, and XopO) have commonly been used as tools to investigate plant immune components. At the same time, the in planta functions of this family of effectors have yet to be fully characterized. In this minireview we summarize current knowledge about the AvrRps4 effector family with emphasis on properties of the proteins themselves. We hypothesize that the HopK1 C-terminus and the AvrRps4 C-terminus, though unrelated in sequence and structure, are broadly related in functions that counteract plant defense responses.

Keywords: HopK1; Pseudomonas; Xanthomonas; XopAK; XopO; effector; pathogen; virulence.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision.

Figures

Figure 1
Figure 1
Visual representations of AvrRps4 effector family homology. (A) Proportional amino acid sequence homology indicated by color and pattern. AvrRps4N-type sequences are indicated in dark green, AvrRps4C-type sequences are indicated in light green, and HopK1C-type sequences are indicated in light blue. NCBI accession numbers for proteins used in this comparison are listed on the left. Percentages between the termini indicate % identity/% positives for each pair as predicted by NCBI’s blastp (Altschul et al., 1990). The ~50AA secretion signals (represented by dots) are included in this comparison but the 12AA central homologous regions (represented by stripes) are not. (B) Protein structural homology with Met1 indicated by an arrow. Structural predictions were made with ColabFold and visualized using ChimeraX (Pettersen et al., 2021; Mirdita et al., 2022).
See this image and copyright information in PMC

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