The Compound 2-Hexyl, 5-Propyl Resorcinol Has a Key Role in Biofilm Formation by the Biocontrol Rhizobacterium Pseudomonas chlororaphis PCL1606.

Claudia E Calderón,Sandra Tienda,Francisco M Cazorla,Gerardo Cárcamo-Oyarce,Leo Eberl,Eva Arrebola,Zaira Heredia-Ponce

doi:10.3389/fmicb.2019.00396

Abstract

The production of the compound 2-hexyl-5-propyl resorcinol (HPR) by the biocontrol rhizobacterium Pseudomonas chlororaphis PCL1606 (PcPCL1606) is crucial for fungal antagonism and biocontrol activity that protects plants against the phytopathogenic fungus Rosellinia necatrix. The production of HPR is also involved in avocado root colonization during the biocontrol process. This pleiotrophic response prompted us to study the potential role of HPR production in biofilm formation. The swimming motility of PcPLL1606 is enhanced by the disruption of HPR production. Mutants impaired in HPR production, revealed that adhesion, colony morphology, and typical air–liquid interphase pellicles were all dependent on HPR production. The role of HPR production in biofilm architecture was also analyzed in flow chamber experiments. These experiments revealed that the HPR mutant cells had less tight unions than those producing HPR, suggesting an involvement of HPR in the production of the biofilm matrix.

Highlights

Members of the genus Pseudomonas possess a substantial amount of metabolic diversity, and many of them are able to colonize a wide range of niches (Madigan and Martinko, 2015)
hexyl-5-propyl resorcinol (HPR) production was detected in the darC, darS, and darR- mutants but at a lower amount when compared with the wild-type strain
All the non-HPR-producing mutants used in this study (Table 1) exhibited increased motility when compared to the wildtype strain

Summary

Introduction

Members of the genus Pseudomonas possess a substantial amount of metabolic diversity, and many of them are able to colonize a wide range of niches (Madigan and Martinko, 2015). The most well-known antibiotics produced by Pseudomonas spp. include 2,4-diacetylphloroglucinol (2,4-DAPG), phenazines (PHZs), pyrrolnitrin (PRN), pyoluteorin (PLT), hydrogen cyanide (HCN), and 2-hexyl-5-propyl resorcinol (HPR; Cazorla et al, 2006; Gross and Loper, 2009). These antibiotics could be directly involved in other different phenotypes related to biocontrol ability in addition to antagonism, such as plant growth promotion and niche competition (Weller, 2007; Ramette et al, 2011; Wang et al, 2015; Raio et al, 2017)

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