Roles of the Gentisate 1,2-Dioxygenases DsmD and GtdA in the Catabolism of the Herbicide Dicamba in Rhizorhabdus dicambivorans Ndbn-20

Abstract

In this study, we identified two gentisate 1,2-dioxygenases (GDOs), DsmD and GtdA, from Ndbn-20. The amino acid sequence similarity between DsmD and GtdA is 51%. Both of them are dimers and showed activities to gentisate and 3-chlorogentisate but not 3,6-dichlorogentisate (3,6-DCGA) or 6-chlorogentisate in vitro. The k cat /K m of DsmD for 3-chlorogentisate was 28.7 times higher than that of GtdA, whereas the k cat /K m of DsmD for gentisate was only one-fourth of that of GtdA. Transcription of dsmD was dramatically induced by 3-chlorogentisate but not gentisate, whereas gtdA was not induced. Disruption of dsmD resulted in a significant decline in the degradation rates of 3-chlorogentisate and dicamba but had no effect on the degradation of gentisate, whereas the result of disruption of gtdA was converse; the disruption of both dsmD and gtdA led to the inability to degrade 3chlorogentisate and gentisate. This study revealed that 3-chlorogentisate but not gentisate or 3,6-DCGA is the ring-cleavage substrate in the dicamba degradation pathway in R. dicambivorans Ndbn-20; DsmD is specifically responsible for cleavage of 3chlorogentisate, whereas GtdA is a general GDO involved in the catabolism of various natural aromatic compounds.

Inhibition of Verticillium Wilt in Cotton through the Application of Pseudomonas aeruginosa ZL6 Derived from Fermentation Residue of Kitchen Waste

“…To construct the gene nml disruption mutant strain, the suicide plasmid pJQ200SK was utilized following a previously published protocol [ 22 ]. A fragment of approximately 525 bp near the 5’ end was amplified via PCR using the primers (KNm-F and KNm-R).…”

Novel Bifunctional Amidase Catalyzing the Degradation of Propanil and Aryloxyphenoxypropionate Herbicides in Rhodococcus sp. C-1

“…The HPLC-HRMS analysis of APPH metabolites by PamC adhered to the procedure detailed in Section . Kinetic data were calculated using the Michaelis–Menten equation ( V = V max × [S]/( K m + [S])) with GraphPad Prism software (version 6.0) . The substrate spectrum assay of PamC was conducted in 1.0 mL of Tris-HCl buffer (20 mM, pH 8.0) with fresh PamC and 0.2 mM of different substrates, including amide herbicides (linuron, diuron, and chlortoluron) or APPHs (FPE, CYB, CFB, QPE, HPM, and FPB), incubated at 30 °C for 10 min.…”

Microbiology and Biochemistry of Pesticides Biodegradation

“…Biodegradation of Dicamba has been documented mainly in bacteria; the experimentally confirmed metabolic pathway involves the dechlorination and demethylation of the molecule to end up with a molecule of 2-chloromaleylpyruvate (Figure 14) [357]; subsequent enzymatic transformation of this molecule has been inferred from the homology analysis of the genes in the operon, where two or three more enzymes participate with a proposed final product of pyruvate and fumarate/maleate. Both of them can be incorporated into the central metabolism of the cell [357].…”

“…2023, 24, x FOR PEER REVIEW 28 of 5 participate with a proposed final product of pyruvate and fumarate/maleate. Both of them can be incorporated into the central metabolism of the cell [357].…”