Sustainable natural bioresources in crop protection: antimicrobial hydroxycoumarins induce membrane depolarization-associated changes in the transcriptome of Ralstonia solanacearum

Background Ralstonia solanacearum is one of the most devastating pathogen affect crop production worldwide. Hydroxycoumarin (umbelliferone, esculetin, daphnetin) imply as sustainable natural bioresources on controlling of plant bacterial wilt. However, the antibacterial mechanism of hydroxycoumarins against plant pathogen still remains poorly understood. Results Here we characterized the effect of three hydroxycoumarins on the transcriptome of R. solanacearum. All three hydroxycoumarins were able to kill R. solanacearum, but their antibacterial activity impacted differently the bacterial transcriptome, indicating that their modes of action might be different. Treatment of R. solanacearum cultures with hydroxycoumarins resulted in a large number of the differentially expressed genes (DEGs), involved in basic cellular functions and metabolic process, such as downregulation of genes involved in fatty acid synthesis, lipopolysaccharides biosynthesis, RNA modification, ribosomal submits, oxidative phosphorylation and electrontransport, as well as upregulation of genes involved in transcriptional regulators, drug efflux, and oxidative stress responses. Future studies based on in vitro experiments are proposed to investigate lipopolysaccharides biosynthesis pathway leading to R. solanacearum cell death caused by hydroxycoumarins. Deletion of lpxB substantially inhibited the growth of R. solanacearum, and reduced virulence of pathogen on tobacco plants. Conculsion Our transcriptomic analyses show that hydroxycoumarins specific suppressed genes expression involved in fatty acid synthesis, RNA modification, ribosomal submits, oxidative phosphorylation and electrontransport. These findings provide evidence that hydroxycoumarins inhibit R. solanacearum growth through affect multi-target effect. Hydroxycoumarins could serve as sustainable natural bioresources against plant bacterial wilt through membrane destruction targeting the lipopolysaccharides biosynthesis pathway. This article is protected by copyright. All rights reserved.