Regulation of Cell Wall-Bound Invertase in Pepper Leaves by Xanthomonas campestris pv. vesicatoria Type Three Effectors

Sonnewald S, Priller J, Schuster J, Glickmann E, Hajirezaei MR, Siebig S, Mudgett MB, Sonnewald U (2012)

Publication Status: Published

Publication Type: Journal article

Publication year: 2012

Journal

PLoS ONE Public Library of Science

Publisher: PUBLIC LIBRARY SCIENCE

Book Volume: 7

Journal Issue: 12

DOI: 10.1371/journal.pone.0051763

Abstract

Xanthomonas campestris pv. vesicatoria (Xcv) possess a type 3 secretion system (T3SS) to deliver effector proteins into its Solanaceous host plants. These proteins are involved in suppression of plant defense and in reprogramming of plant metabolism to favour bacterial propagation. There is increasing evidence that hexoses contribute to defense responses. They act as substrates for metabolic processes and as metabolic semaphores to regulate gene expression. Especially an increase in the apoplastic hexose-to-sucrose ratio has been suggested to strengthen plant defense. This shift is brought about by the activity of cell wall-bound invertase (cw-Inv). We examined the possibility that Xcv may employ type 3 effector (T3E) proteins to suppress cw-Inv activity during infection. Indeed, pepper leaves infected with a T3SS-deficient Xcv strain showed a higher level of cw-Inv mRNA and enzyme activity relative to Xcv wild type infected leaves. Higher cw-Inv activity was paralleled by an increase in hexoses and mRNA abundance for the pathogenesis-related gene PRQ. These results suggest that Xcv suppresses cw-Inv activity in a T3SS-dependent manner, most likely to prevent sugar-mediated defense signals. To identify Xcv T3Es that regulate cw-Inv activity, a screen was performed with eighteen Xcv strains, each deficient in an individual T3E. Seven Xcv T3E deletion strains caused a significant change in cw-Inv activity compared to Xcv wild type. Among them, Xcv lacking the xopB gene (Xcv Delta xopB) caused the most prominent increase in cw-Inv activity. Deletion of xopB increased the mRNA abundance of PRQ in Xcv Delta xopB-infected pepper leaves, but not of Pti5 and Acre31, two PAMP-triggered immunity markers. Inducible expression of XopB in transgenic tobacco inhibited Xcv-mediated induction of cw-Inv activity observed in wild type plants and resulted in severe developmental phenotypes. Together, these data suggest that XopB interferes with cw-Inv activity in planta to suppress sugar-enhanced defense responses during Xcv infection. Citation: Sonnewald S, Priller JPR, Schuster J, Glickmann E, Hajirezaei M-R, et al. (2012) Regulation of Cell Wall-Bound Invertase in Pepper Leaves by Xanthomonas campestris pv. vesicatoria Type Three Effectors. PLoS ONE 7(12): e51763. doi:10.1371/journal.pone.0051763

Authors with CRIS profile

Sophia Sonnewald Lehrstuhl für Biochemie Johannes Priller Lehrstuhl für Biochemie Uwe Sonnewald Lehrstuhl für Biochemie

Involved external institutions

Stanford University US United States (USA) (US) Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) / Leibniz Institute of Plant Genetics and Crop Plant Research DE Germany (DE)

How to cite

APA:

Sonnewald, S., Priller, J., Schuster, J., Glickmann, E., Hajirezaei, M.-R., Siebig, S.,... Sonnewald, U. (2012). Regulation of Cell Wall-Bound Invertase in Pepper Leaves by Xanthomonas campestris pv. vesicatoria Type Three Effectors. PLoS ONE, 7(12). https://dx.doi.org/10.1371/journal.pone.0051763

MLA:

Sonnewald, Sophia, et al. "Regulation of Cell Wall-Bound Invertase in Pepper Leaves by Xanthomonas campestris pv. vesicatoria Type Three Effectors." PLoS ONE 7.12 (2012).

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