Code-cracking TAL effector function and evolution in the rice-Xanthomonas oryzae system
A. PEREZ-QUINTERO (1), M. Hutin (2), T. Tran (3), A. Derepeer (4), S. Cunnac (1), L. Gagnevin (4), B. Szurek (4) (1) UMR IPME, IRD-CIRAD-Université Montpellier 2, France; (2) Department of Plant Pathology and Plant-Microbe Biology, Cornell University, U.S.A.; (3) Agricultural Genetics Institute, Vietnam; (4) UMR IPME, IRD-CIRAD-Université Montpellier 2, France

Transcription Activator-Like (TAL) effectors from Xanthomonas plant pathogenic bacteria can bind to the promoter region of plant genes and induce their expression. DNA-binding specificity is governed by a central domain made of nearly identical repeats, each determining the recognition of one base pair via two amino acid residues. Inferring functional and evolutionary relationships between TAL effectors is often challenging due to their repetitive nature. We thus developed the suite QueTAL to offer tailored tools for comparison of TAL effector genes: The program DisTAL can be used to align repetitive regions of TAL effectors and assess events of recombination between repeats. And the program FuncTAL is aimed at finding TAL effectors with similar DNA-binding capabilities. The programs accurately represented phylogenetic and functional relationships between TAL effectors using either simulated or literature-curated data. We used these programs to infer evolutionary patterns of these effectors in African strains from X. oryzae pv oryzae (Xoo), the causing agent of bacterial leaf blight in rice, this revealed different mechanisms of TAL effector evolution and highlighted the importance of recombination for the generation of new TAL effector variants. Finally, we used RNAseq to understand how different variants can contribute to virulence, this revealed some novel features of TAL effector activity that can be used to further improve predictions and functional analyses.

Abstract Number: C8-4, P12-405
Session Type: Concurrent