Photosynthetic and respiratory changes in leaves of poplar elicited by rust infection. Photosynth Res

Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Stn. Sainte-Foy, Quebec, QC, Canada.
Photosynthesis Research (Impact Factor: 3.5). 12/2009; 104(1):41-8. DOI: 10.1007/s11120-009-9507-2
Source: PubMed


Poplars are challenged by a wide range of pathogens during their lifespan, and have an innate immunity system that activates defence responses to restrict pathogen growth. Large-scale expression studies of poplar-rust interactions have shown concerted transcriptional changes during defence responses, as in other plant pathosystems. Detailed analysis of expression profiles of metabolic pathways in these studies indicates that photosynthesis and respiration are also important components of the poplar response to rust infection. This is consistent with our current understanding of plant pathogen interactions as defence responses impose substantive demands for resources and energy that are met by reorganization of primary metabolism. This review applies the results of poplar transcriptome analyses to current research describing how plants divert energy from plant primary metabolism for resistance mechanisms.

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    • "During susceptible responses, poplar genes associated with photosynthesis were downregulated while genes associated with carbon metabolism and respiration were upregulated 6 to 9 d after initial attack (Miranda et al. 2007, Azaiez et al. 2009). In susceptible plants, downregulation of photosynthesis has been proposed as a plant strategy to favor processes like respiration over assimilatory metabolic processes to generate defense resources (Major et al. 2010), whereas in resistant plants, the upregulation of various genes associated with photosynthesis has been proposed to supply the carbon skeletons, energy, and reducing equivalents needed to mount defenses against invaders. As the leaf tissue sampled for these investigations with poplar trees was located near (on the same leaf) infection sites, these results would be most comparable with our results for leaf three (the directly attacked leaf), which showed a slight increases of photosynthesis for both resistant and susceptible Hessian fly-attacked plants. "
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    • "This suggests that the reduction in net assimilation rate in E. alphitoides infected Q. robur leaves was associated with reductions in the amount and/or activity of rate-limiting proteins such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Impairment of stomatal conductance and photosynthesis and resulting enhanced water loss in infected plants have also been observed in other studies (Robert et al. 2005, Major et al. 2009). In addition, despite the parallel reductions in net assimilation rate and stomatal conductance in downy mildew Peronospora plantaginis-infected Plantago ovata leaves, intercellular CO 2 concentration actually increased in infected leaves, also indicating that the demand for CO 2 decreased relatively more than the supply of CO 2 (Mandal et al. 2009). "
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