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Title: Diverse MarR bacterial regulators of auxin catabolism in the plant microbiome
Abstract Chemical signalling in the plant microbiome can have drastic effects on microbial community structure, and on host growth and development. Previously, we demonstrated that the auxin metabolic signal interference performed by the bacterial genusVariovoraxvia an auxin degradation locus was essential for maintaining stereotypic root development in an ecologically relevant bacterial synthetic community. Here, we dissect theVariovoraxauxin degradation locus to define the genesiadDEas necessary and sufficient for indole-3-acetic acid (IAA) degradation and signal interference. We determine the crystal structures and binding properties of the operon’s MarR-family repressor with IAA and other auxins. Auxin degradation operons were identified across the bacterial tree of life and we define two distinct types on the basis of gene content and metabolic products:iac-like andiad-like. The structures of MarRs from representatives of each auxin degradation operon type establish that each has distinct IAA-binding pockets. Comparison of representative IAA-degrading strains from diverse bacterial genera colonizingArabidopsisplants show that while all degrade IAA, only strains containingiad-like auxin-degrading operons interfere with auxin signalling in a complex synthetic community context. This suggests thatiad-like operon-containing bacterial strains, includingVariovoraxspecies, play a key ecological role in modulating auxins in the plant microbiome.  more » « less
Award ID(s):
1917270
PAR ID:
10376376
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
Nature Publishing Group
Date Published:
Journal Name:
Nature Microbiology
Volume:
7
Issue:
11
ISSN:
2058-5276
Page Range / eLocation ID:
p. 1817-1833
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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