Transcriptomic responses to cadmium in the ectomycorrhizal fungus Paxillus involutus.
The molecular mechanisms underlying the response of ectomycorrhizal fungi to heavy metals in general and cadmium in particular remain poorly understood. We screened 2040 arrayed cDNAs of the ectomycorrhizal fungus Paxillus involutus to identify cadmium-responsive genes by using differential hybridization. Forty nine (2.4%) of the 2040 cDNAs were differentially expressed, among which transcripts coding a laccase, an aconitase, and a metallothionein were upregulated by 3.9-, 3.7- and 2.8-fold, respectively, whereas genes coding hydrophobins and threonine dehydratase were strongly downregulated. Our results suggest that complexation of cadmium by phenolic compounds, or by complexing peptides such as metallothioneins, is probably key determinant of the cellular response to cadmium in P. involutus. In addition, the present study suggests that the synthesis of hydrophobins may be efficiently reduced, thus redirecting Cys to the manufacture of Cys-enriched compounds.
Jacob
Christophe
C
UMR INRA/UHP 1136, Interactions Arbres Micro-organismes, Université Henri Poincaré-Nancy I, Faculté des Sciences et Techniques, BP239, 54506 Vandoeuvre-les-Nancy, France.
Courbot
Mikaël
M
Martin
Francis
F
Brun
Annick
A
Chalot
Michel
M
D001487:Basidiomycota / Q000187:drug effects / Q000235:genetics*; D002104:Cadmium / Q000494:pharmacology*; D004156:Catechol Oxidase / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D042845:Laccase / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D012331:RNA, Fungal / Q000235:genetics / Q000302:isolation & purification; D014158:Transcription, Genetic / Q000187:drug effects*
D018076:DNA, Complementary; D005656:Fungal Proteins; D012331:RNA, Fungal; D002104:Cadmium; D004156:Catechol Oxidase; D042845:Laccase