Abstract

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 tran- script abundance in Pinus sylvestris L. root tissues infected by Heterobasidion annosum (Fr.) Bref. s.l., a cDNA microarray containing2109ESTsfromP.taedaL.wasused.Mixedmodel statistical analysis identified 179 expressed sequence tags dif- ferentially expressed at 1, 5 or 15 days post inoculation. In gen- eral, 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-re- lated proteins with antimicrobial properties. A class III peroxidase responsible for lignin biosynthesis and cell wall thickening had increased transcript abundance at all measure- ment times. Real-time RT-PCR verified the microarray results with high reproducibility. The similarity of the expression pro- filing pattern observed in this pathosystem to those docu- mented in crop pathology suggests that angiosperms and gym- nosperms use similar genetic programs in responding to inva- sive growth by microbial pathogens.

Published in

Tree Physiology
2007, volume: 27, number: 10, pages: 1441-1458

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