AUTHOR=Arrebola Eva , Cazorla Francisco M. 

TITLE=Aer Receptors Influence the Pseudomonas chlororaphis PCL1606 Lifestyle

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.01560

DOI=10.3389/fmicb.2020.01560

ISSN=1664-302X

ABSTRACT=<p><italic>Pseudomonas chlororaphis</italic> PCL1606 (PcPCL1606) is a rhizobacterium isolated from avocado roots, which is a favorable niche for its development. This strain extensively interacts with plant roots and surrounding microbes and is considered a biocontrol rhizobacterium. Genome sequencing has shown the presence of thirty-one potential methyl-accepting chemotaxis proteins (MCPs). Among these MCPs, two candidates are putative functional aerotaxis receptors, encoded at locus PCL1606_41090 (<italic>aer</italic>1-1) and locus PLC1606_20530 (<italic>aer</italic>1-2), that are homologous to the Aer receptor of <italic>Pseudomonas aeruginosa</italic> strain PaO1. Single- and double-deletion mutants in one or both genes have led to motility deficiencies in oxygen-rich areas, particularly reduced swimming motility compared with that of wildtype PcPCL1606. No differences in swarming tests were detected, and less adhesion by the <italic>aer</italic> double mutant was observed. However, the single and double mutants on avocado plant roots showed delayed biocontrol ability. During the first days of the biocontrol experiment, the <italic>aer</italic>-defective mutants also showed delayed root colonization. The current research characterizes the presence of <italic>aer</italic> transductors on <italic>P. chlororaphis</italic>. Thus, the functions of the PCL1606_41090 and PCL1606_20530 loci, corresponding to genes <italic>aer</italic>1-1 and <italic>aer</italic>1-2, respectively, are elucidated.</p>