ArabidopsisbZIP11 is a susceptibility factor duringPseudomonas syringaeinfection

Abstract

AbstractThe induction of plant nutrient secretion systems is critical for successful pathogen infection. Some bacterial pathogens,e.g. Xanthomonasspecies, use TAL (transcription activator-like) effectors to induce transcription of SWEET sucrose efflux transporters.Pseudomonas syringaepathovar (pv.)tomatostrain DC3000 lacks TAL effectors, yet is able to induce multiple SWEETs inArabidopsis thalianaby unknown mechanisms. Since bacteria require other nutrients besides sugars for efficient reproduction, we hypothesized thatPseudomonasmay depend on host transcription factors involved in secretory programs to increase access to essential nutrients. Bioinformatic analyses identified theArabidopsisbasic-leucine zipper transcription factor bZIP11 as a potential regulator of nutrient transporters, including SWEETs and UmamiT amino acid transporters. Inducible downregulation ofbZIP11expression inArabidopsisresulted in reduced growth ofP. syringaepv.tomatostrain DC3000, whereas inducible overexpression ofbZIP11resulted in increased bacterial growth, supporting the hypothesis that bZIP11 regulated transcription programs are essential for maximal pathogen titer in leaves. Our data are consistent with a model in which a pathogen alters host transcription factor expression upstream of secretory transcription networks to promote nutrient efflux from host cells.