EffectorP 3.0: Prediction of Apoplastic and Cytoplasmic Effectors in Fungi and Oomycetes

• Published in: Molecular plant-microbe interactions Vol. 35; no. 2; pp. 146 - 156
• Main Authors: Sperschneider, Jana, Dodds, Peter N.
• Format: Journal Article
• Language: English
• Published: United States American Phytopathological Society 01.02.2022; The American Phytopathological Society
• Subjects: Amino acids; Apoplast; artificial intelligence; Cysteine; Cytoplasm; Cytoplasm - metabolism; Effectors; Fungal Proteins - metabolism; Fungi; fungus–plant interactions; Homology; Host plants; Learning algorithms; Machine learning; Oomycetes; Oomycetes - metabolism; oomycete–plant interactions; Pathogens; Plant Diseases - microbiology; Plants - microbiology; prediction; Predictions; Proteins; sequence homology; signal peptide; oomycete–plant interactions; fungus–plant interactions
• ISSN: 0894-0282; 1943-7706; 1943-7706
• DOI: 10.1094/MPMI-08-21-0201-R

Many fungi and oomycete species are devasting plant pathogens. These eukaryotic filamentous pathogens secrete effector proteins to facilitate plant infection. Fungi and oomycete pathogens have diverse infection strategies and their effectors generally do not share sequence homology. However, they occupy similar host environments, either the plant apoplast or plant cytoplasm, and, therefore, may share some unifying properties based on the requirements of these host compartments. Here, we exploit these biological signals and present the first classifier (EffectorP 3.0) that uses two machine-learning models: one trained on apoplastic effectors and one trained on cytoplasmic effectors. EffectorP 3.0 accurately predicts known apoplastic and cytoplasmic effectors in fungal and oomycete secretomes with low estimated false-positive rates of 3 and 8%, respectively. Cytoplasmic effectors have a higher proportion of positively charged amino acids, whereas apoplastic effectors are enriched for cysteine residues. The combination of fungal and oomycete effectors in training leads to a higher number of predicted cytoplasmic effectors in biotrophic fungi. EffectorP 3.0 expands predicted effector repertoires beyond small, cysteine-rich secreted proteins in fungi and RxLR-motif containing secreted proteins in oomycetes. We show that signal peptide prediction is essential for accurate effector prediction, because EffectorP 3.0 recognizes a cytoplasmic signal also in intracellular, nonsecreted proteins. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .