AUTHOR=Maldonado-González M. Mercedes , Bakker Peter A. H. M. , Prieto Pilar , Mercado-Blanco Jesús 

TITLE=Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

JOURNAL=Frontiers in Microbiology

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2015.00266

DOI=10.3389/fmicb.2015.00266

ISSN=1664-302X

ABSTRACT=<p>The effective management of Verticillium wilts (VW), diseases affecting many crops and caused by some species of the soil-borne fungus <italic>Verticillium</italic>, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. <italic>Pseudomonas fluorescens</italic> PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control VW of olive caused by the highly virulent, defoliating (D) pathotype of <italic>Verticillium dahliae</italic> Kleb. However, the study of the PICF7-<italic>V. dahliae</italic>-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant <italic>Arabidopsis thaliana</italic>. Results obtained in this study showed that: (i) olive D and non-defoliating <italic>V. dahliae</italic> pathotypes produce differential disease severity in <italic>A. thaliana</italic> plants; (ii) strain PICF7 is able to colonize and persist in the <italic>A. thaliana</italic> rhizosphere but is not endophytic in <italic>Arabidopsis</italic>; and (iii) strain PICF7 controls VW in <italic>Arabidopsis</italic>. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in<italic> A. thaliana</italic>, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled <italic>Botrytis cinerea</italic> infection in the leaves of <italic>Arabidopsis</italic>, suggesting that this strain is able to induce systemic resistance. <italic>A. thaliana</italic> is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of <italic>V. dahliae</italic> by <italic>P. fluorescens</italic> PICF7.</p>