Background: The monolignol biosynthetic pathway interconnects with the biosynthesis of other secondary phenolic metabolites, such as cinnamic acid derivatives, flavonoids and condensed tannins. The objective of this study is to evaluate whether genetic modification of the monolignol pathway in silver birch (Betula pendula Roth.) would alter the metabolism of these phenolic compounds and how such alterations, if exist, would affect the ectomycorrhizal symbiosis.
Results: Silver birch lines expressing quaking aspen (Populus tremuloides L.) caffeate/5-hydroxyferulate O-methyltransferase (PtCOMT) under the 35S cauliflower mosaic virus (CaMV) promoter showed a reduction in the relative expression of a putative silver birch COMT (BpCOMT) gene and, consequently, a decrease in the lignin syringyl/guaiacyl composition ratio. Alterations were also detected in concentrations of certain phenolic compounds. All PtCOMT silver birch lines produced normal ectomycorrhizas with the ectomycorrhizal fungus Paxillus involutus (Batsch: Fr.), and the formation of symbiosis enhanced the growth of the transgenic plants.
Conclusion: The down-regulation of BpCOMT in the 35S-PtCOMT lines caused a reduction in the syringyl/guaiacyl ratio of lignin, but no significant effect was seen in the composition or quantity of phenolic compounds that would have been caused by the expression of PtCOMT under the 35S or UbB1 promoter. Moreover, the detected alterations in the composition of lignin and secondary phenolic compounds had no effect on the interaction between silver birch and P. involutus.
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http://dx.doi.org/10.1186/1471-2229-9-124 | DOI Listing |
Tree Physiol
December 2024
Institute of Ecology and Earth Sciences, University of Tartu, J. Liivi 2, 50409 Tartu, Estonia.
Scenarios for future climate predict an increase in precipitation amounts and frequency of rain events, resulting in higher air humidity and soil moisture at high latitudes, including in northern Europe. We analysed the effects of artificially elevated environmental humidity (air relative humidity and soil moisture) on leaf gas exchange, water relations, growth and phenology of silver birch (Betula pendula) trees growing at the Free Air Humidity Manipulation (FAHM) experimental site situated in the hemiboreal vegetation zone, in eastern Estonia, with no occurring water deficit to the trees. The environmental humidity manipulation did not significantly affect the water relations traits but did affect some leaf gas exchange parameters, growth and phenology of the trees.
View Article and Find Full Text PDFTree Physiol
December 2024
Optics of Photosynthesis Laboratory, Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Viikki Plant Science Center, University of Helsinki, Helsinki, FI 00014, Finland.
Understanding the diurnal and seasonal regulation of photosynthesis is an essential step to quantify and model the impact of the environment on plant function. Although the dynamics of photosynthesis have been widely investigated in terms of CO2 exchange measurements, a more comprehensive view can be obtained when combining gas-exchange and chlorophyll fluorescence (ChlF). Until now, integrated measurements of gas-exchange and ChlF have been restricted to short-term analysis using portable IRGA systems that include a fluorometer module.
View Article and Find Full Text PDFSci Total Environ
December 2024
Forest Resources Management, Institute of Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland.
Climate change is exacerbating forest disturbances through more frequent and more intense droughts and fires, undermining their ability to recover from such disturbances. The response of fast-growing early-successional species to drought is poorly understood, despite their key role in ecological succession and their ability to enhance ecosystem resilience. Here, we compared the growth responses to drought events of three early-successional species (silver birch, black poplar, and Scots pine) with that of one late-successional species (European beech) across their natural distribution ranges in Europe.
View Article and Find Full Text PDFMolecules
August 2024
Institute of Forest Sciences, Białystok University of Technology, 15-351 Białystok, Poland.
Pharmaceuticals (Basel)
August 2024
Institute of Forestry and Engineering, Chair of Silviculture and Forest Ecology, Estonian University of Life Sciences, Kreutzwaldi 5, 51006 Tartu, Estonia.
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