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

Boron stress, oxidative damage and antioxidant protection in potato cultivars (Solanum tuberosum L.)

WOS: 000370549900002Six potato cultivars grown in Turkey in boron-prone areas and differing in their tolerance towards high boron were studied to reveal whether boron causes oxidative stress. To assess stress level, chlorophyll fluorescence and growth parameters were measured. Oxidative damage was assessed as malondialdehyde level, and antioxidant protection was evaluated as ascorbate (AA), dehydroascorbate, reduced glutathione (GSH) and oxidized glutathione amounts and superoxide dismutase, catalase, ascorbate peroxidase (APX) and glutathione reductase (GR) activities. High boron stress affected photosynthesis negatively in a threshold-dependent manner and inhibited growth. No pronounced changes in oxidation of lipids occurred in any cultivar. Activation of APX suggested the involvement of an ascorbic acid-reduced glutathione cycle in the protection against oxidative stress caused by high boron. Efficient work of this antioxidant system was probably hindered by boron complexation with NAD(P)(+)/NAD(P)H and resulted in the inhibition of GR and a decrease in AA and GSH. Hence, oxidative stress associated with high boron is a secondary component of boron toxicity which arises from metabolic changes caused by boron interference with major metabolites. Potato cultivars tolerate excess boron stress well and show damage only in very high boron concentrations. The potato cvs best suited for high boron soils/breeding purposes are cvs Van Gogh and Agria. Abbreviations: AA: ascorbic acid; APX: ascorbate peroxidase; CAT: catalase; DHA: dehydroascorbic acid; DHAR: dehydroascorbate reductase; DTNB: 5; 5 '-dithiobis-2-nitrobenzoic acid; DTT: dithiotreitol; F-v/F-m: photosynthetic efficiency at the dark-adapted state; GR: glutathione reductase; GSH: reduced glutathione; GSSG: oxidized glutathione; MDA: malondialdehyde; ROS: reactive oxygen species; SOD: superoxide dismutase; TCA: trichloroacetic acidHelsinki University; Department of Biosciences and Scientific Research Projects of Ege UniversityEge University [2004/FEN/026]; Center for International Mobility for Finland (CIMO); Foundation for Environmental Protection and Research (FEPR)This study was supported by Helsinki University, Department of Biosciences and Scientific Research Projects of Ege University [Project number: 2004/FEN/026]. Financial support from the Center for International Mobility for Finland (CIMO) and Foundation for Environmental Protection and Research (FEPR) to M.A. as a graduate student is gratefully acknowledged

Exploring the Monolignol transport mechanisms in Norway spruce

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