JXB Advance Access published online on May 21, 2009
Journal of Experimental Botany, doi:10.1093/jxb/erp147
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© 2009 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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RESEARCH PAPER |
Plant–pathogen interactions and elevated CO2: morphological changes in favour of pathogens
Department of Animal and Plant Sciences, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
* To whom correspondence should be addressed: j.a.lake{at}sheffield.ac.uk
Crop losses caused by pests and weeds have been estimated at 42% worldwide, with plant pathogens responsible for almost $10 billion worth of damage in the USA in 1994 alone. Elevated carbon dioxide [ECO2] and associated climate change have the potential to accelerate plant pathogen evolution, which may, in turn, affect virulence. Plant–pathogen interactions under increasing CO2 concentrations have the potential to disrupt both agricultural and natural systems severely, yet the lack of experimental data and the subsequent ability to predict future outcomes constitutes a fundamental knowledge gap. Furthermore, nothing is known about the mechanistic bases of increasing pathogen agressiveness. In the absence of information on crop species, it is shown here that plant pathogen (Erysiphe cichoracearum) aggressiveness is increased under ECO2, together with changes in the leaf epidermal characteristics of the model plant Arabidopsis thaliana L. Stomatal density, guard cell length, and trichome numbers on leaves developing post-infection are increased under ECO2 in direct contrast to non-infected responses. As many plant pathogens utilize epidermal features for successful infection, these responses provide a positive feedback mechanism facilitating an enhanced susceptibility of newly developed leaves to further pathogen attack. Furthermore, a screen of resistant and susceptible ecotypes suggest inherent differences in epidermal responses to ECO2.
Key words: ABA, carbon dioxide, global change, plant–pathogen interactions, stomatal density, trichomes
Received 25 November 2008; Revised 4 March 2009 Accepted 9 April 2009