A Plant Pathogen Type III Effector Protein Subverts Translational Regulation to Boost Host Polyamine Levels

• Published in: Cell host & microbe Vol. 26; no. 5; pp. 638 - 649.e5
• Main Authors: Wu, Dousheng, von Roepenack-Lahaye, Edda, Buntru, Matthias, de Lange, Orlando, Schandry, Niklas, Pérez-Quintero, Alvaro L., Weinberg, Zasha, Lowe-Power, Tiffany M., Szurek, Boris, Michael, Anthony J., Allen, Caitilyn, Schillberg, Stefan, Lahaye, Thomas
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 13-11-2019
• Subjects: arginine decarboxylase (ADC); Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Carboxy-Lyases - genetics; Carboxy-Lyases - metabolism; Host Microbial Interactions - genetics; microbiota; Plant Diseases - microbiology; Plant Leaves - metabolism; Plant Roots - metabolism; Plants - microbiology; polyamines; Polyamines - metabolism; Protein Biosynthesis - genetics; putrescine; Ralstonia solanacearum; Ralstonia solanacearum - genetics; Ralstonia solanacearum - metabolism; rhizosphere; translational regulation; type III effectors; upstream open reading frame (uORF); microbiota; Ralstonia solanacearum; arginine decarboxylase (ADC); translational regulation; upstream open reading frame (uORF); polyamines; putrescine; type III effectors; rhizosphere
• ISSN: 1931-3128; 1934-6069
• DOI: 10.1016/j.chom.2019.09.014

Pathogenic bacteria inject effector proteins into host cells to manipulate cellular processes and facilitate the infection. Transcription-activator-like effectors (TALEs), an effector class in plant pathogenic bacteria, transcriptionally activate host genes to promote disease. We identify arginine decarboxylase (ADC) genes as the host targets of Brg11, a TALE-like effector from the plant pathogen Ralstonia solanacearum. Brg11 targets a 17-bp sequence that was found to be part of a conserved 50-bp motif, termed the ADC-box, upstream of ADC genes involved in polyamine biosynthesis. The transcribed ADC-box attenuates translation from native ADC mRNAs; however, Brg11 induces truncated ADC mRNAs lacking the ADC-box, thus bypassing this translational control. As a result, Brg11 induces elevated polyamine levels that trigger a defense reaction and likely inhibits bacterial niche competitors but not R. solanacearum. Our findings suggest that Brg11 may give R. solanacearum a competitive advantage and uncover a role for bacterial effectors in regulating ternary microbe-host-microbe interactions.
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•A Ralstonia solanacearum TALE activates host ADC genes•Due to a truncated 5′ UTR, the TALE-induced ADC mRNA subverts translational control•ADCs inhibit in planta growth of Pseudomonas syringae but not of R. solanacearum•Brg11-induced responses possibly aid R. solanacearum by hindering niche competitors
Plant pathogen transcription-activator-like effectors (TALEs) activate host genes to promote disease. Wu et al. identify a 17-bp sequence upstream of arginine decarboxylase (ADC) genes that is targeted by TALE-like Brg11 from Ralstonia solanacearum. Brg11 induces 5′-truncated ADC transcripts that subvert translational control and lead to inhibition of potentially competing pathogens.