Comparative secretome analysis of Zymoseptoria tritici isolates and Dothideomycete species to identify conserved secreted effector proteins

Authors: GOMEZ, SANDRA - PURDUE UNIVERSITY; Goodwin, Stephen - Steve; GRIBSKOV, MICHAEL - PURDUE UNIVERSITY

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/21/2022
Publication Date: 1/13/2023
Citation: Gomez, S., Goodwin, S.B., Gribskov, M. 2023. Comparative secretome analysis of Zymoseptoria tritici isolates and Dothideomycete species to identify conserved secreted effector proteins. Plant and Animal Genome 30. 13-18 Jan 2023, San Diego, CA.

Interpretive Summary:

Technical Abstract: Zymoseptoria tritici (Zt) is the cause of Septoria tritici blotch in wheat crops. This disease has an asymptomatic stage for 1–13 days, followed by a rapid transition to necrotrophy. Pathogens secrete effectors that modulate innate immunity of the plant and can overcome pattern-triggered immunity mechanisms to facilitate infection. Effector molecules from fungal pathogens are small, secreted proteins (SSPs). They typically are fewer than 300 amino acids in length, are cysteine-rich, contain signal peptides at the N-terminus, and lack transmembrane domains. Proteins of five Zt isolates and seven Dothideomycete species with representative lifestyles within the class were retrieved from JGI Mycocosm and NCBI databases. Functional domain annotations were conducted using BLAST+ 2.12.0., Pfam v.35.0, dbCAN, and the MEROPs protease database. Secreted proteins were identified by the presence of signal peptides and the absence of transmembrane domains detected by Phobius v1.01, Target P v.2.0. and SignalP v4.1. EffectorP v.3.0, ApoplastP and LOCALIZER were applied to identify effector features and predict the localization of the effectors within the plant cell. The four European isolates of Zt showed the highest number of secreted proteins among all the organisms. The Zt IPO323 strain has similar numbers of SSPs and predicted effector proteins as Cladosporium fulvum and Parastagonospora nodorum. A clustering analysis was conducted to identify conserved predicted effectors among the Dothideomycete species, and at least two clusters that contain effectors with significant sequence similarity were identified among all the species. We identified shared effectors in 11 species including non-pathogens Baudoinea compniacensis and Cryomyces antarcticus.