The influence of the ectomycorrhizal fungus Rhizopogon subareolatus on growth and nutrient element localisation in two varieties of Douglas fir (Pseudotsuga menziesii var. menziesii and var. glauca) in response to manganese stress

Abstract

Acidification of forest ecosystems leads to increased plant availability of the micronutrient manganese (Mn), which is toxic when taken up in excess. To investigate whether ectomycorrhizas protect against excessive Mn by improving plant growth and nutrition or by retention of excess Mn in the hyphal mantle, seedlings of two populations of Douglas fir (Pseudotsuga menziesii), two varieties, one being menziesii (DFM) and the other being glauca (DFG), were inoculated with the ectomycorrhizal fungus Rhizopogon subareolatus in sand cultures. Five months after inoculation, half of the inoculated and non-inoculated seedlings were exposed to excess Mn in the nutrient solution for further 5 months. At the end of this period, plant productivity, nutrient concentrations, Mn uptake and subcellular compartmentalisation were evaluated. Non-inoculated, non-stressed DFM plants produced about 2.5 times more biomass than similarly treated DFG. Excess Mn in the nutrient solution led to high accumulation of Mn in needles and roots but only to marginal loss in biomass. Colonisation with R. subareolatus slightly suppressed DFM growth but strongly reduced that of DFG (−50%) despite positive effects of mycorrhizas on plant phosphorus nutrition. Growth reductions of inoculated Douglas fir seedlings were unexpected since the degree of mycorrhization was not high, i.e. ca. 30% in DFM and 8% in DFG. Accumulation of high Mn was not prevented in inoculated seedlings. The hyphal mantle of mycorrhizal root tips accumulated divalent cations such as Ca, but not Mn, thus not providing a barrier against excessive Mn uptake into the plants associated with R. subareolatus.

Comparative Mitochondrial Genome Analysis of Two Ectomycorrhizal Fungi (Rhizopogon) Reveals Dynamic Changes of Intron and Phylogenetic Relationships of the Subphylum Agaricomycotina

“…Through their ectomycorrhizal relationships, Rhizopogon species obtains carbon sources necessary for growth, and in exchange they provide trees with access to water and mineral nutrients [1]. In addition, ectomycorrhizal fungi, e.g., Rhizopogon spp., promote plant growth, enhance plant resistance to stress and maintain the forest ecosystem [6,7,8]. The genus Rhizopogon is diverse, with more than 150 species described [3,9,10].…”

Subcellular Nutrient Element Localization and Enrichment in Ecto- and Arbuscular Mycorrhizas of Field-Grown Beech and Ash Trees Indicate Functional Differences

“…Potassium, which is mainly localized to cell walls and cytosol of root cells, was not affected by fungal colonization [17] . P containing storage granules were found together with Mg and K in fungal vacuoles using EDX-TEM (transmission electron microscopy) [15] , [19] , [23] , [24] .…”

A catalogue of putative unique transcripts from Douglas-fir (Pseudotsuga menziesii) based on 454 transcriptome sequencing of genetically diverse, drought stressed seedlings

“…In Europe, the area of Douglas-fir production is rising [12]. Forest practitioners appreciate the resistance of Douglas-fir against many European pathogens [13,14]. It is also expected that Douglas-fir is better adapted to future climate conditions in Central Europe than e.g.…”

“…For this reason, it is important for forest managers to select suitable tree species or provenances that are adapted to the anticipated future climate. Currently, coastal Douglas-fir provenances are more frequently planted in Central Europe due to their superior growth performance compared to interior Douglas-firs [13,14,20]. The identification and characterization of differentially adapted provenances of coastal and interior Douglas-fir varieties has therefore high practical value.…”