Multiple acquisitions of XopJ2 effectors in populations of Xanthomonas perforans

• Published in: Molecular plant-microbe interactions Vol. 37; no. 10; pp. 736 - 747
• Main Authors: Sharma, Anuj, Iruegas-Bocardo, Fernanda, Bibi, Shaheen, Chen, Yun-Chu, Kim, Jung-Gun, Abrahamian, Peter, Minsavage, Gerald V, Hurlbert, Jason C, Vallad, Gary E, Mudgett, Mary B, Jones, Jeffrey B, Goss, Erica M
• Format: Journal Article
• Language: English
• Published: United States The American Phytopathological Society 01.10.2024
• Subjects: acetyltransferase; AvrBsT; tomato; type III effector; Xanthomonas
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI-05-24-0048-R

Type III effectors (T3Es) are major determinants of virulence and targets for resistance breeding. XopJ2 (syn. AvrBsT) is a highly conserved YopJ-family T3E acquired by , the pathogen responsible for bacterial spot disease of tomato. In this study, we characterized a new variant (XopJ2b) of XopJ2, which is predicted to have a similar 3D structure as the canonical XopJ2 (XopJ2a) despite sharing only 70% sequence identity. XopJ2b carries an acetyltransferase domain and the critical residues required for its activity, and the positions of these residues are predicted to be conserved in 3D structure of the proteins. We demonstrated that XopJ2b is a functional T3E and triggers hypersensitive response when translocated into pepper cells. Like XopJ2a, XopJ2b triggers HR in that is suppressed by the deacetylase, SOBER1. We found in genome sequences of , , , , and strains, suggesting widespread horizontal transfer. In , was present in strains collected in North and South America, Africa, Asia, Australia, and Europe, whereas had a more narrow geographic distribution. This study expands the T3E repertoire, demonstrates functional conservation in T3E evolution, and further supports the importance of XopJ2 in fitness on tomato.