ISSN:
1432-2048
Keywords:
Key words: Auxin-induced genes
;
Auxin
;
Betaine
;
Ectomycorrhiza
;
Hypaphorine
;
Root formation
;
Root hair
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract. A full-length cDNA coding for a symbiosis-regulated transcript, EgHypar, was isolated by differential screening from a Eucalyptus globulus bicostata–Pisolithus tinctorius ectomycorrhiza. The sequence of this clone revealed a protein with an estimated molecular mass of 25.5 kDa that exhibited a high degree of homology (66%) with plant auxin-induced glutathione-S-transferases. Expression of the EgHypar gene in seedlings was confined largely in roots and it is drastically increased by ectomycorrhiza development. The concentration of EgHypar transcripts was similarly up-regulated in roots incubated in media supplemented with P. tinctorius cell-free extracts, indole-3-acetic acid, 2,4-dichlorophenoxyacetic acid or hypaphorine (tryptophan betaine), the major indolic compound secreted by P. tinctorius. The latter fungal alkaloid concomitantly induced a decrease in root hair elongation in eucalypt seedlings. Up-regulation of EgHypar expression by auxins and fungal metabolites suggests that this symbiosis-regulated gene could be involved in the morphological changes taking place in plants roots upon symbiosis development. To our knowledge, these results provide the first molecular evidence that gene expression of the host plant is altered by molecules produced by the ectomycorrhizal mycobiont.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004250050486
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