Record ID No. |
593 |
Author(s) |
Reddy S .M., Pandey A.K., Melayah D., Marmeisse R., Gay G* , 2003 |
Affiliation |
*University of Lyon 1,CNRS,UMR Ecol Microbienne,Bat A Lwoff 43 Blvd 11 Novembre 1918,F-69622 Villeurbanne,France |
Title |
The auxin responsive gene Pp-C61 is up-regulated in Pinus pinaster roots following inoculation with ectomycorrhizal fungi |
Source. Vol.(no):Page |
Plant Cell and Environment, 26(5): 681-691p. |
Categories |
Ectomycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Hormones |
Host |
Pinus pinaster |
Organism |
Hebeloma cylindrosporum, Rhizopogon roseolus |
Country |
France, Europe |
Abstracts |
An indoleacetic acid (IAA) up-regulated cDNA, referred to as Pp-C61, teas isolated by differential screening of a cDNA library constructed from auxin-treated roots of Pinus pinaster. The Pp-C61 cDNA contains a 1068 by open reading frame which encodes a polypeptide sharing no homology with known proteins. The N-terminal protein region contains a hydrophobic signal peptide suggesting that Pp-C61 is an extracellular protein. Pp-C61 is present as a single copy in the P. Pinaster genome and homologous genes were detected in other gymnosperm and angiosperm trees. Pp-C61 was transcriptionally regulated by auxin with a maximal mRNA accumulation 6 h after treatment. Pp-C61 was up-regulated by IAA concentrations as low as 10(-10) M. Up-regulation was found to be a primary (direct) response to auxin. Ethylene and abscisic acid, but not quercetin were able to promote Pp-C61 mRNA accumulation. As a putative extracellular protein, Pp-C61 was postulated to play a role in ectomycorrhiza formation: Pp-C61 was upregulated in P. Pinaster roots following inoculation with ectomycorrhizal fungi. Transcript accumulation was the highest (5.5-fold over control) in the presence of an IAA-overproducing mutant of Hebeloma cylindrosporum; it was less in the presence of wild-type strains of H. Cylindrosporum and Rhizopogon roseolus. Pp-C61 transcript also accumulated upon inoculation with a non-mycorrhizal mutant of H. Cylindrosporum. These results suggest that Pp-C61 up-regulation corresponds to a defence reaction in response to fungal colonization. |