Proma Plasmids are Instrumental in the Dissemination of Linuron Catabolic Genes between Different Genera

Abstract

28PromA plasmids are broad host range plasmids, which are often cryptic and hence 29 have an uncertain ecological role. We present three novel PromA γ plasmids which 30 carry genes associated with degradation of the phenylurea herbicide linuron, two 31 (pPBL-H3-2 and pBPS33-2) of which originate from unrelated Hydrogenophaga 32 hosts isolated from different environments, and one (pEN1) which was 33 exogenously captured from an on-farm biopurification system. Both 34 Hydrogenophaga plasmids carry all three necessary gene clusters determining the 35 three main steps for conversion of linuron to Krebs cycle intermediates, while 36 pEN1 only determines the initial linuron hydrolysis step. Linuron catabolic gene 37 clusters that determine the same step were identical on all plasmids, encompassed 38 in differently arranged constellations and characterized by the presence of multiple 39 IS1071 elements. In all plasmids except pEN1, the insertion spot of the catabolic 40 genes in the PromA γ plasmids was the same. Highly similar PromA plasmids 41 carrying the linuron degrading gene cargo at the same insertion spot were were 42 previously identified in linuron degrading Variovorax sp. Interestingly, in both 43 Hydrogenophaga populations not every PromA plasmid copy carries catabolic 44 genes. The results indicate that PromA plasmids are important vehicles of linuron 45 catabolic gene dissemination, rather than being cryptic and only important for the 46 mobilization of other plasmids. 47 48 49 4 WERNER ET AL.

Biosolids for safe land application: does wastewater treatment plant size matters when considering antibiotics, pollutants, microbiome, mobile genetic elements and associated resistance genes?

“…PromA, IncN and IncP‐1 all have a broad host range and might serve as shuttles for RG dissemination between species. This is the first study reporting the potentially concerning prevalence of PromA plasmids in WWTP biosolids, because PromA plasmids possess mobilization and self‐transfer capabilities potentiating transfer of resistance carrying plasmids (Werner et al ., 2020). Presence of IncW and IncN plasmids was reported in previous WWTPs studies (Akiyama et al ., 2010; Hutinel et al ., 2021).…”