Details

Autor(en) / Beteiligte

• Wright, D. P.
• Scholes, J. D.
• Read, D. J.
• Rolfe, S. A.

Titel

Changes in carbon allocation and expression of carbon transporter genes in Betula pendula Roth. colonized by the ectomycorrhizal fungus Paxillus involutus (Batsch) Fr

Ist Teil von

• Plant, cell and environment, 2000-01, Vol.23 (1), p.39-49

Ort / Verlag

Oxford, UK: Blackwell Science Ltd

Erscheinungsjahr

2000

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• ABSTRACT Comparative analyses of aspects of the carbon (C) physiology and the expression of C transporter genes in birch (Betula pendula Roth.) colonized by the ectomycorrhizal fungus Paxillus involutus (Batsch) Fr. were performed using mycorrhizal (M) and non‐mycorrhizal (NM) plants of similar foliar nutrient status. After six months of growth, the biomass of M plants was significantly lower than that of NM plants. Diurnal C budgets of both sets of plants revealed that M plants exhibited higher rates of photosynthesis and root respiration expressed per unit dry weight. However, the diurnal net C gain of M and NM plants remained similar. Ectomycorrhizal roots contained higher soluble carbohydrate pools and increased activity of cell wall invertase, suggesting that additional C was allocated to these roots and their ectomycorrhizal fungi consistent with an increased sink demand for C due to the presence of the mycobiont. In M roots, the expression of two hexose and one sucrose transporter genes of birch were reduced to less than one‐third of the expression level observed in NM roots. Analysis using a probe against the birch ribosomal internal transcribed spacer region revealed that M roots contained 22% less plant RNA than NM roots. As the expression of birch hexose and sucrose transporter genes was reduced to a much greater extent, this suggests that these specific genes were down‐regulated in response to alterations in C metabolism within M roots.