Gene Ontology annotation through association of InterPro records with GO terms

A single bacterial genus maintains root growth in a complex microbiome.

Identified a conserved auxin-degradation operon across Variovorax genomes that is necessary and sufficient for reverting auxin- and microbiome-induced root growth inhibition.

"We identify an auxin-degradation operon that is conserved in all available genomes of Variovorax and is necessary and sufficient for the reversion of root growth inhibition."

Diverse MarR bacterial regulators of auxin catabolism in the plant microbiome.

Demonstrated by gain-of-function and knockout genetics that iadD and iadE are necessary and sufficient for indole-3-acetic acid (IAA) degradation in Variovorax, and that co-expression of iadC accelerates IAA degradation to revert Arthrobacter-induced root growth inhibition.

"To test the necessity of these genes, we constructed knockout strains CL14 ΔiadDE and CL14 ΔiadCDE. Both lacked the ability to degrade IAA (Fig. 1d), demonstrating that iadD and iadE are necessary and sufficient for IAA degradation by Variovorax."
Established by LC-MS/MS metabolomics that the Variovorax iad pathway degrades IAA through dioxindole-3-acetic acid and isatin to anthranilic acid.

"The intermediates dioxindole, isatin and isatinic acid, and the product anthranilic acid were all detected and thus produced in the bacterial cultures."

Structural and biochemical characterization of the key components of an auxin degradation operon from the rhizosphere bacterium Variovorax.

Solved the 1.8 A crystal structure (PDB 7YLS) and 2.6 A IAA-bound cryo-EM structure (PDB 8H2T) of Variovorax paradoxus S110 IadD/IadE, revealing a mushroom-shaped heterohexamer where each IadD subunit coordinates a Rieske [2Fe-2S] cluster (Cys85, His87, Cys106, His109) and a mononuclear iron center (His216, His221, Asp377).

"The active site of IadD is located at the interface of IadD subunits, composed of a Rieske [2Fe-2S] cluster from the Rieske domain and a mononuclear iron in the catalytic domain of a neighboring subunit (Figs 3D and S5A and S5B). The [2Fe-2S] is stabilized by contacts with Cys85, His87, Cys106, and His109 and the mononuclear iron coordinates with His216, His221, and Asp377."
Demonstrated in vitro reconstitution of IAA dioxygenation to 2-oxindole-3-acetic acid (oxIAA) by purified IadD/IadE and IadC in the presence of NADH and O2.

"Together, these data suggest that IAA was converted to oxIAA by the dioxygenase system composed of the IadD/E dioxygenase and the IadC reductase (Fig 5E)."

UniProtKB:C5CSP6

UniProtKB record for C5CSP6 (C5CSP6_VARPS)

Contains an N-terminal Rieske [2Fe-2S] domain and aromatic-ring-hydroxylating dioxygenase alpha subunit signatures.

"DR InterPro; IPR001663; Rng_hydr_dOase-A."