Record ID No. |
348 |
Author(s) |
Balestrini, R., Cosgrove, D.J., Bonfante, P* , 2005 |
Affiliation |
*University of Turin, CNR, Ist Protez Piante, Sez Micol, Viale Mattioli 25, I-10125 Turin, Italy |
Title |
Differential location of alpha-expansin proteins during the accommodation of root cells to an arbuscular mycorrhizal fungus |
Source. Vol.(no):Page |
Planta. 220(6), 889-899p. |
Categories |
Arbuscular Mycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Host |
cucumber |
Organism |
Glomus versiforme |
Country |
Italy, Asia |
Abstracts |
α-Expansins are extracellular proteins that increase plant cell-wall extensibility. We analysed their pattern of expression in cucumber roots in the presence and in the absence of the mycorrhizal fungus, Glomus versiforme. The distribution of α-expansins was investigated by use of two polyclonal antibodies (anti-EXPA1 and anti-EXPA2, prepared against two different cucumber α-expansins) in immunoblotting, immunofluorescence, and immunogold experiments. Immunoblot results indicate the presence of a 30-kDa band specific for mycorrhizal roots. The two antibodies identify antigens with a different distribution in mycorrhizal roots: anti-EXPA1 labels the interface zone, but the plant cell walls only weakly. By contrast, the anti-EXPA2 labels only the plant cell walls. In order to understand the potential role of α-expansins during the accommodation of the fungus inside root cells, we prepared semi-thin sections to measure the size of cortical cells and the thickness of cortical cell walls in mycorrhizal and non-mycorrhizal root. Mycorrhizal cortical cells were significantly larger than non-mycorrhizal cells and had thicker cell walls. In double-labelling experiments with cellobiohydrolase-gold complex, we observed that cellulose was co-localized with α-expansins. Taken together. the results demonstrate that α-expansins are more abundant in the cucumber cell walls upon mycorrhizal infection; we propose that these wall-loosening proteins are directly involved in the accommodation of the fungus by infected cortical cells. |