Innate immunity: has poplar made its BED?

Authors

  • Hugo Germain,

    1. Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du PEPS, PO Box 10380, Stn Sainte-Foy, Québec, QC, G1V 4C7, Canada
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  • Armand Séguin

    1. Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du PEPS, PO Box 10380, Stn Sainte-Foy, Québec, QC, G1V 4C7, Canada
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Author for correspondence:
Hugo Germain
Tel: +1 418 648 4925
Email: hugo.germain@nrcan.gc.ca

Abstract

Contents

 Summary678
I.Introduction679
II.R-gene-mediated response in plants: an introductory overview679
III.R-protein pathways in poplar680
IV.What is the role of BED-NB-LRR?681
V.Downstream of R-proteins683
VI.The role of salicylic acid in biotrophic interaction683
VII.Concluding remarks684
 References685

Summary

The perennial plant model species Populus trichocarpa has received considerable attention in the last 5 yr because of its potential use as a bioenergy crop. The completion of its genome sequence revealed extensive homologies with the herbaceous annual species Arabidopsis thaliana. This review highlights the similarities and differences at the qualitative defence response components level, notably in putative NBS-LRR protein content and downstream defence regulators. With almost a twofold NBS-LRR gene complement compared with A. thaliana, P. trichocarpa also encodes some putative R-proteins with unusual architectures and possible DNA-binding capacity. P. trichocarpa also possesses all the known main components characteristic of TIR-NB-LRR and CC-NB-LRR signalling. However, very little has been done with regard to the components involved in the poplar qualitative response to pathogens. In addition, the relationship between plant-biotroph perception/signalling and the role of salicylic acid, an important defence compound, remains uncertain. This review aims to identify the genomic components present in poplar that could potentially participate in the qualitative response and highlights where efforts should be devoted to obtain a better understanding of the poplar qualitative defence response.

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