© 2007 Heron Publishing—Victoria, Canada
Transcript profiling of a conifer pathosystem: response of Pinus sylvestris root tissues to pathogen (Heterobasidion annosum) invasion
Aleksandra Adomas (1, 2), Gregory Heller (1), Guosheng Li (1), Åke Olson (1), Tzu-Ming Chu (3), Jason Osborne (4), Deborah Craig (5), Lee van Zyl (5), Russ Wolfinger (3), Ron Sederoff (5), Ralph A. Dean (6), Jan Stenlid (1), Roger Finlay (1) and Frederick O. Asiegbu (1)
1. Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, Uppsala, Sweden / 2. Corresponding author (aleksandra.adomas@mykopat.slu.se) / 3. SAS Institute, Cary, NC 27513, USA / 4. Department of Statistics, Box 8203, North Carolina State University, Raleigh, NC 27695, USA / 5. Forest Biotechnology Laboratory, Box 7247, North Carolina State University, Raleigh, NC 27695, USA / 6. Fungal Genomics Laboratory, Box 7251, North Carolina State University, Raleigh, NC 27695, USA / Received December 11, 2006; accepted February 5, 2007; published online July 3, 2007
Summary
The mechanisms underlying defence reactions to a pathogen attack, though well studied in crop plants, are poorly understood
in conifers. To analyze changes in gene transcript abundance in Pinus sylvestris L. root tissues infected by Heterobasidion annosum (Fr.) Bref. s.l., a cDNA microarray containing 2109 ESTs from P. taeda L. was used. Mixed model statistical analysis identified 179 expressed sequence tags differentially expressed at 1, 5 or
15 days post inoculation. In general, the total number of genes differentially expressed during the infection increased over
time. The most abundant group of genes up-regulated upon infection coded for enzymes involved in metabolism (phenylpropanoid
pathway) and defence-related proteins with antimicrobial properties. A class III peroxidase responsible for lignin biosynthesis
and cell wall thickening had increased transcript abundance at all measurement times. Real-time RT-PCR verified the microarray
results with high reproducibility. The similarity of the expression profiling pattern observed in this pathosystem to those
documented in crop pathology suggests that angiosperms and gymnosperms use similar genetic programs in responding to invasive
growth by microbial pathogens.
Keywords:
antimicrobial peptide, microarray, peroxidase, phenylopropanoid pathway, pine, plant defence.
