Pro-domain processing of fungal effector proteins from plant pathogens

The generated peptides are biologically active and form tightly bound amyloid-like fibrils on the hyphal surface that repel water and facilitate the proper formation of aerial hyphae and hyphal attachment [2,3]. Ala, alanine; Arg, arginine; Glu, glutamic acid; Ile, isoleucine; K2PP, Kex2-processed pro-domain; Leu, leucine; Lys, lysine; Pro, proline; RiPP, ribosomally synthesised and post-translationally modified peptide; Thr, threonine; Val, valine. https://doi.org/10.1371/journal.ppat.1010000.g001 The second class of cleaved fungal effectors are processed via the removal of a pro-domain from the N-terminus of the effector [7] (Fig 1A). Effectors in this class were originally identified based on the presence of a canonical Kex2 protease cleavage motif and the absence of the proceeding N-terminal region of the protein (putative pro-domain) when isolated from source [7–12]. To search for putative K2PP effectors, we constrained our analysis to the first half of the effector protein sequences and searched for disorder promoting amino acids that proceeded canonical Kex2 cleavage motifs (KR, RR) or the expanded motif (LxxR) (Fig 1B) [7].