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Review
. 2020 Apr 24;1(4):100050.
doi: 10.1016/j.xplc.2020.100050. eCollection 2020 Jul 13.

All Roads Lead to Susceptibility: The Many Modes of Action of Fungal and Oomycete Intracellular Effectors

Qin He  1   2 , Hazel McLellan  2 , Petra C Boevink  3 , Paul R J Birch  2   3
Affiliations
Review

All Roads Lead to Susceptibility: The Many Modes of Action of Fungal and Oomycete Intracellular Effectors

Qin He et al. Plant Commun. .

Abstract

The ability to secrete effector proteins that can enter plant cells and manipulate host processes is a key determinant of what makes a successful plant pathogen. Here, we review intracellular effectors from filamentous (fungal and oomycete) phytopathogens and the host proteins and processes that are targeted to promote disease. We cover contrasting virulence strategies and effector modes of action. Filamentous pathogen effectors alter the fates of host proteins that they target, changing their stability, their activity, their location, and the protein partners with which they interact. Some effectors inhibit target activity, whereas others enhance or utilize it, and some target multiple host proteins. We discuss the emerging topic of effectors that target negative regulators of immunity or other plant proteins with activities that support susceptibility. We also highlight the commonly targeted host proteins that are manipulated by effectors from multiple pathogens, including those representing different kingdoms of life.

Keywords: defense; effectors; fungi; immunity; oomycete; susceptibility factor.

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Figures

Figure 1
Figure 1
Processes Targeted by Filamentous Phytopathogen Effector Proteins. The pie chart shows the percentage of effectors that interact with host proteins from each biological category; total numbers of effectors are indicated in brackets. Within each pie segment, the numbers indicate oomycete (outer ring) or fungal (inner ring) effectors within that category.
Figure 2
Figure 2
Plant Targets and Modes of Action of Filamentous Phytopathogen Effectors. Effectors are shown in yellow. Positive regulators of immunity are shown in blue, and negative regulators of immunity are shown in red. The mode of action of the effectors is written in purple text, with an upward arrow denoting increase and a downward arrow denoting decrease.
Figure 3
Figure 3
Effectors Target Both Positive and Negative Regulators of Immunity. (A) The pie chart shows the percentage of effectors that interact with host proteins that positively or negatively regulate immunity; actual effector numbers are indicated on the chart. (B) The stacked column bar chart shows the percentage of effectors that target both positive and negative defense regulators from each biological category; actual effector numbers are indicated on the chart.
Figure 4
Figure 4
Effectors that Interact with Multiple Host Targets and Interfere with Different Processes. Effectors are shown in yellow. Effector targets that are positive regulators of immunity are shown in blue, and negative regulators of immunity are shown in red. Pathogens and MAMPs are shown in brown. BIC, biotrophic interfacial complex; Ub, ubiquitin; K+, potassium ions; ICD, INF1-triggered cell death.
See this image and copyright information in PMC

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