The Rhizobacterium Pseudomonas alcaligenes AVO110 Induces the Expression of Biofilm-Related Genes in Response to Rosellinia necatrix Exudates.

Adrián Pintado,Antonio De Vicente,Cayo Ramos,Francisco M Cazorla,José Antonio Gutiérrez-Barranquero,Isabel Pérez-Martínez,Isabel M Aragón

doi:10.3390/microorganisms9071388

Abstract

The rhizobacterium Pseudomonas alcaligenes AVO110 exhibits antagonism toward the phytopathogenic fungus Rosellinia necatrix. This strain efficiently colonizes R. necatrix hyphae and is able to feed on their exudates. Here, we report the complete genome sequence of P. alcaligenes AVO110. The phylogeny of all available P. alcaligenes genomes separates environmental isolates, including AVO110, from those obtained from infected human blood and oyster tissues, which cluster together with Pseudomonas otitidis. Core and pan-genome analyses showed that P. alcaligenes strains encode highly heterogenic gene pools, with the AVO110 genome encoding the largest and most exclusive variable region (~1.6 Mb, 1795 genes). The AVO110 singletons include a wide repertoire of genes related to biofilm formation, several of which are transcriptionally modulated by R. necatrix exudates. One of these genes (cmpA) encodes a GGDEF/EAL domain protein specific to Pseudomonas spp. strains isolated primarily from the rhizosphere of diverse plants, but also from soil and water samples. We also show that CmpA has a role in biofilm formation and that the integrity of its EAL domain is involved in this function. This study contributes to a better understanding of the niche-specific adaptations and lifestyles of P. alcaligenes, including the mycophagous behavior of strain AVO110.

Highlights

In recent years, multitrophic interactions have gained the attention of many research groups because of their importance in plant disease development and the assembly of root-associated microbiomes [1,2,3,4,5]
(4406) are within the range of the other 10 P. alcaligenes and two P. pseudoalcaligenes genomes currently available at National Center for Biotechnology Information (NCBI), two of which correspond to the P. alcaligenes type strain deposited in two collections (NCTC 10367 and NBRC 14159)
The genomes of P. alcaligenes strains isolated from infected human blood (MRY13-0052) or oyster tissues (OT 69) were, on average, approximately 2.5 Mb larger than those of strains isolated from water

Summary

Introduction

Multitrophic interactions have gained the attention of many research groups because of their importance in plant disease development and the assembly of root-associated microbiomes [1,2,3,4,5]. These interactions modulate the colonization and establishment of microorganisms in different environments and ecological niches [6], including the plant rhizosphere [7]. Bacterial mycophagy was first demonstrated in a soil bacterium of the Collimonas genus [13], which became the model bacterium for disentangling the mechanisms governing this feature [14,15,16,17,18,19,20]

Methods

Results

Conclusion