Comprehensive prediction of plant cytoplasmic and apoplastic effectors underlying Erwinia psidii pathogenicity. (15th September 2022)

• Record Type: Journal Article
• Authors: Alves, Francisco Henrique Nunes da Silva; Pereira, Isadora Cristófoli; dos Santos, Samuel Alves; Monteiro, Ana Leticia Rocha; Vidigal, Pedro Marcus Pereira; Alfenas, Acelino Couto; Badel, Jorge Luis
• Is Part Of: Plant pathology. Volume 72:Number 1(2023)
• Page Start: 130
• Page End: 143
• Publication Date: 2022-09-15
• Subjects: eucalypt -- guava -- Sec/Tat secretion -- type III secretion -- virulence; Agricultural pests -- Periodicals; Plant diseases -- Periodicals; 632
• DOI: 10.1111/ppa.13636
• Languages: English
• ISSNs: 0032-0862

Abstract

Abstract: Erwinia psidii (Eps) is the causal agent of emerging diseases of eucalypt and guava; however, the mechanisms underlying its pathogenicity are not fully understood. Here, we predicted factors involved in the ability of Eps to cause disease on its host plants. For that, the genomes of four Eps strains exhibiting different virulence on eucalypt were sequenced, and hrp / hrc genes coding for the type III secretion system (T3SS), effectors injected into the plant cell cytoplasm through the T3SS (T3SEs) and their plant subcellular localizations, as well as proteins deployed to the host apoplast, were predicted. It was found that Eps possesses a complete hrp / hrc gene cluster based on comparison with Erwinia amylovora . A total of 18 T3SEs were predicted, 11 of which were shared among all strains, none were exclusive to any strain and seven were absent in at least one strain. No sequence variation among strains was found for five T3SE candidates whereas extensive variation was found for six, suggesting the latter may be determinants of virulence differences. The T3SE candidates are predicted to target the plant cell nucleus, cytoplasm, mitochondrion, chloroplast and peroxisome. The predicted apoplastic effector repertoire common to all four strains was over‐represented in proteins of unknown functions or predicted to possess enzymatic activities, among which the most abundant were oxidoreductases and peptidases. Proteins with lytic transglycosylase activity were predicted in strain‐specific apoplastic effector repertoires. These results provide an important framework for future research aimed at uncovering the factors underlying Eps pathogenicity. Abstract : Genome sequencing and bioinformatic analysis identified 18 type III and diverse apoplastic effectors with predicted unknown or enzymatic activities putatively associated with the ability of Erwinia psidii to infect its host plants.