Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch

Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.Peer reviewe

Author Correction: Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch.

In the version of this article initially published, there was a mistake in the calculation of the nucleotide mutation rate per site per generation: 1 × 10−9 mutations per site per generation was used, whereas 9.5 × 10−9 was correct. This error affects the interpretation of population-size changes over time and their possible correspondence with known geological events, as shown in the original Fig. 4 and supporting discussion in the text, as well as details in the Supplementary Note. Neither the data themselves nor any other results are affected. Figure 4 has been revised accordingly. Images of the original and corrected figure panels are shown in the correction notice

Dehydrins in Scots pine tissues: Responses to annual rhythm, low temperature and nitrogen (väitöskirja)

väitöskirj

Dehydrins in Scots pine tissues:responses to annual rhythm, low temperature and nitrogen

Abstract Natural seasonal variation and the effects of cold treatment and nitrogen fertilization on protein expression with special emphasis on dehydrin proteins, were studied using different aged Scots pine (Pinus sylvestris L.). Several different dehydrins were found and their expression depended on the tissue type, tree age or specific treatment. Their concentrations fluctuated seasonally and in response to nitrogen fertilization, but no effects of low temperature on the dehydrins of seedlings were observed. A 60-kDa dehydrin was associated with cold acclimation in the bud and bark tissues of mature trees and in the needles of seedlings. In the needles of mature trees, this dehydrin was associated with springtime desiccation, which was detected as a significant decrease in the osmotic potential of needles. The quantity and quality of soluble proteins altered seasonally in Scots pine tissues, but low temperature treatment alone did not have any effect on the proteins. Soluble protein concentration increased during autumn and decreased in spring in buds and bark, but not in the needles of mature trees. In needles of seedlings, however, protein concentrations altered seasonally. Several proteins, of varying molecular weights, were more abundant in winter in all the tissues studied and some increased in concentration in the nitrogen-fertilized seedlings. The role of these proteins as a storage reserve in Scots pine is discussed. The osmotic potential of needles showed seasonal fluctuation, being high in the summer and low during the winter. Low temperature treatment decreased the osmotic and water potential of needles and increased the concentrations of soluble sugars in seedlings. Based on carbohydrate analyses, the metabolism of seedlings acclimated to low temperature in less than ten days. Nitrogen fertilization increased the content of total nitrogen and the soluble protein concentrations in the needles of seedlings and the growth both in the mature trees and seedlings. Although the frost resistance showed no response to nitrogen-fertilization, the soluble proteins and dehydrins were affected in a manner that suggested an earlier growth resumption of spring in the fertilized trees

Tree provenance affects the growth and bioenergy potential of juvenile silver birch

The ever-growing need for renewable resources for energy production makes us look more closely at biomass reserves so far unused and considered insufficient in terms of energy content, availability or cost. In this study we present the first results of the calorific values and chemical composition of the branches of 12 micropropagated silver birch (Betula pendula) genotypes originating from 60°N to 67°N. The birches were planted at two different latitudes in Finland (62°N and 67°N) in a common garden experiment and harvested in juvenile stage during their fifth annual growth in Joensuu (62°N) in 2015 and during the sixth year in Kolari (67°N) in 2016. The results highlighted the calorific value ranges and their fair south-north gradient, while opposite trend was observed for the mass of branches upon harvest (green weight). The highest amount of extractives in branches was 15% w/w with methanol while water (13%) and acetone (10%) were also considered fairly efficient. Our preliminary results indicate that while the energy content and chemical composition vary by 12.5% along the latitudes of birch provenances, the most significant contribution to the available feedstock for bioenergy comes from branch quantity, being significantly higher in genotypes of southern latitudes grown in either of the common gardens. The indicated differences between the assessed genotypes based on preliminary description of data seem more profound in the trees grown in Joensuu (62°N)) than in Kolari (67°N)), possibly due to longer growing period and more substantial biomass yield in general able to differentiate between samples.201

Susceptibility of silver birch (Betula pendula) to herbivorous insects is associated with the size and phenology of birch – implications for climate warming

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High Variation in Resource Allocation Strategies among 11 Indian Wheat (Triticum aestivum) Cultivars Growing in High Ozone Environment

Eleven local cultivars of wheat (Triticum aestivum) were chosen to study the effect of ambient ozone (O3) concentration in the Indo-Gangetic Plains (IGP) of India at two high-ozone experimental sites by using 300 ppm of Ethylenediurea (EDU) as a chemical protectant against O3. The O3 level was more than double the critical threshold reported for wheat grain production (AOT40 8.66 ppm h). EDU-grown plants had higher grain yield, biomass, stomatal conductance and photosynthesis, less lipid peroxidation, changes in superoxide dismutase and catalase activities, changes in content of oxidized and reduced glutathione compared to non-EDU plants, thus indicating the severity of O3 induced productivity loss. Based on the yield at two different growing sites, the cultivars could be addressed in four response groups: (a) generally well-adapted cultivars (above-average yield); (b) poorly-adapted (below-average yield); (c) adapted to low-yield environment (below-average yield); and (d) sensitive cultivars (adapted to high-yield environment). EDU responses were dependent on the cultivar, the developmental phase (vegetative, flowering and harvest) and the experimental site