The nucleotide sequence of Pp-GH3.16 appears in the EMBL/GenBank/DDBJ Nucleotide Sequence Databases under accession number AM042714.
The auxin-inducible GH3 homologue Pp-GH3.16 is downregulated in Pinus pinaster root systems on ectomycorrhizal symbiosis establishment
Article first published online: 14 MAR 2006
Volume 170, Issue 2, pages 391–400, April 2006
How to Cite
Reddy, S. M., Hitchin, S., Melayah, D., Pandey, A. K., Raffier, C., Henderson, J., Marmeisse, R. and Gay, G. (2006), The auxin-inducible GH3 homologue Pp-GH3.16 is downregulated in Pinus pinaster root systems on ectomycorrhizal symbiosis establishment. New Phytologist, 170: 391–400. doi: 10.1111/j.1469-8137.2006.01677.x
- Issue published online: 14 MAR 2006
- Article first published online: 14 MAR 2006
- Received: 22 November 2005 Accepted: 23 December 2005
- auxin-regulated gene;
- Hebeloma cylindrosporum;
- Pinus pinaster
- • In an attempt to determine whether auxin-regulated plant genes play a role in ectomycorrhizal symbiosis establishment, we screened a Pinus pinaster root cDNA library for auxin-upregulated genes. This allowed the identification of a cDNA, Pp-GH3.16, which encodes a polypeptide sharing extensive homologies with GH3 proteins of different plants.
- • Pp-GH3.16 was specifically upregulated by auxins and was not affected by cytokinin, gibberellin, abscisic acid or ethylene, or by heat shock, water stress or anoxia.
- • Pp-GH3.16 mRNAs were quantified in pine roots inoculated with two ectomycorrhizal fungi, Hebeloma cylindrosporum and Rhizopogon roseolus. Surprisingly, Pp-GH3.16 was downregulated following inoculation with both fungal species. The downregulation was most rapid on establishment of symbiosis with an indole-3-acetic acid (IAA)-overproducing mutant of H. cylindrosporum, which overproduced mycorrhizas characterized by a hypertrophic Hartig net. This indicates that, despite being auxin-inducible, Pp-GH3.16 can be downregulated on establishment of symbiosis with a fungus that releases auxin.
- • By contrast, Pp-GH3.16 was not downregulated in pine root systems inoculated with a nonmycorrhizal mutant of H. cylindrosporum, suggesting that the downregulation we observed in mycorrhizal root systems was a component of the molecular cross-talk between symbiotic partners at the origin of differentiation of symbiotic structures.