Project description:Paenarthrobacter strains effectively degrade the fungicide iprodione, exhibiting a specialization rarely seen amongst bacteria. The transformation of iprodione is controlled by an amidase, a deacetylase and a hydrolase encoded by ipaH, ddaH and duaH respectively. We aimed to elucidate the mechanisms of this catabolic specialization and its evolution in Paenarthrobacters. The genomes of two new iprodione-degrading Paenarthrobacter strains TA1.8 and C1 were sequenced and analyzed comparatively with the genomes of two other iprodione-degrading Paenarthrobacter strains YJN-5 and YJN-D. Comparative genomics revealed different gene organization motifs amongst strains which suggest that the strains are at different stages of pathway evolution, in accord with their prior exposure to iprodione. Strains TA1.8, YJN-5 and YJN-D, all isolated from soils heavily exposed to iprodione, carried multiple copies of ipaH, ddaH and duaH in their chromosomes and plasmids that were assigned to two distinct phylogenetic clusters based on genome topology. Conversely, strain C1, isolated from a pristine soil, carried ipaH, ddaH and duaH in the chromosome. Pangenome analysis of the genus Paenarthrobacter placed ipaH and duaH in the core genome reinforcing their specialization in the degradation of iprodione as they need to acquire only ddaH, the sole gene of the pathway associated with transposable elements in strains C1 and TA1.8, to complete the pathway. We propose an evolution route of the iprodione transformation pathway which involves acquisition of ddaH through horizontal gene transfer, gene duplication of the chromosomally encoded ipaH and ddaH, and further genetic rearrangements for pathway optimization, complementing duaH, a core gene in Paenarthrobacters. Transcriptomic analysis of strain TA1.8 verified the involvement of all copies of ipaH, ddaH and duaH in the transformation of iprodione, and identified hydantoinases, upregulated during iprodione degradation, as potential facilitators of the transformation of the hydantoin-containing intermediate N-(3,-5-dichlorophenyl)- 2,4-dioxoimida-zolidine, a step mediated by DdaH.
Project description:Paenarthrobacter nicotinovorans pAO1 is a nicotine degrading microorganism that shows promising applications in converting nicotine-containing waste into useful green chemicals. Its biotechnological applications are nevertheless hampered by the lack of knowledge and tools to perform genetic and metabolic engineering. The objective of the work is to provide the first transcriptome of the strain and is a second step in our envisioned complete omics characterization of nicotine metabolism in P. nicotinovorans ATCC 49919. Acknowledgements. This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS - UEFISCDI, project number PN-III-P4-ID-PCE-2020-0656, within PNCDI III.