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The tryptophan betaine, hypaphorine, produced by Pisolithus
tinctorius during ectomycorrhizal infection is readily
absorbed and metabolised by Eucalyptus globulus, the host
pant
Poster
session: Physiology (1)
BEGUIRISTAIN THIERRY & FREDERIC LAPEYRIE
Equipe de Microbiologie Forestière, I.N.R.A., Centre de
Nancy, 54280 Champenoux, France
ICOM1 Abstract
Hypaphorine the betaine of tryptophan, is over-accumulated in
Pisolithus tinctorius tissues as soon as hyphae are in
contact with host plant, Eucalyptus globulus, root surface.
This phenomenon observed, 24 hours after inoculation was
recorded as well in several month old ectomycorrhizae. P.
tinctorius synthesise hypaphorine from externally applied
14C-tryptophan and 14C-hypaphorine was
purified by HPLC.
Eucalyptus globulus seedlings incubated in fungal
hypaphorine were taking up hypaphorine at a slightly lower
rate than tryptophan. Consequently, after 9 hours, E.
globulus over-accumulated in roots a yet non-identified
compound RAC-11 (Root Aromatic Compound, 11 min. retention
time). RAC-11 is synthesised by E. globulus from
14C-hypaphorine (15% of absorbed hypaphorine), but
not from 14C-tryptophan. Apart from RAC-11,
absorbed 14C-hypaphorine was recovered in roots
mainly as hypaphorine (20%) and tryptophan (10%).