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Deciphering the genetic control of flowering and ripening periods in apple is essential for breeding cultivars adapted to their growing environments. We implemented a large Genome-Wide Association Study (GWAS) at the European level using an association panel of 1,168 different apple genotypes distributed over six locations and phenotyped for these phenological traits. The panel was genotyped at a high-density of SNPs using the Axiom®Apple 480 K SNP array. We ran GWAS with a multi-locus mixed model (MLMM), which handles the putatively confounding effect of significant SNPs elsewhere on the genome. Genomic regions were further investigated to reveal candidate genes responsible for the phenotypic variation. At the whole population level, GWAS retained two SNPs as cofactors on chromosome 9 for flowering period, and six for ripening period (four on chromosome 3, one on chromosome 10 and one on chromosome 16) which, together accounted for 8.9 and 17.2% of the phenotypic variance, respectively. For both traits, SNPs in weak linkage disequilibrium were detected nearby, thus suggesting the existence of allelic heterogeneity. The geographic origins and relationships of apple cultivars accounted for large parts of the phenotypic variation. Variation in genotypic frequency of the SNPs associated with the two traits was connected to the geographic origin of the genotypes (grouped as North+East, West and South Europe), and indicated differential selection in different growing environments. Genes encoding transcription factors containing either NAC or MADS domains were identified as major candidates within the small confidence intervals computed for the associated genomic regions. A strong microsynteny between apple and peach was revealed in all the four confidence interval regions. This study shows how association genetics can unravel the genetic control of important horticultural traits in apple, as well as reduce the confidence intervals of the associated regions identified by linkage mapping approaches. Our findings can be used for the improvement of apple through marker-assisted breeding strategies that take advantage of the accumulating additive effects of the identified SNPs.

The frequency and severity of drought in the Western United States have significantly increased. California endemic blue oaks (Quercus douglasii) are predicted to be negatively impacted by extreme drought and are already experiencing dieback in the driest areas of their distribution. To explore whether there is drought‐adaptive variation among blue oak populations, we conducted a greenhouse common garden drought experiment with seedlings from five sites along a range‐wide precipitation gradient. We investigated seedling performance under experimental drought (fluorescence/maximum fluorescence [Fv/Fm], stomatal conductance, and leaf desiccation). We measured physiological and morphological traits, including average leaf area, specific leaf area (SLA), leaf margin morphology, C:N, and carbon isotope discrimination (δ13C, a proxy for water use efficiency). We used generalized linear mixed models to understand the relationship between seedling performance and traits, and the mean annual precipitation (MAP) of the seedling source site. We found significant relationships between source site MAP and Fv/Fm, percent of green leaves, and plant stomatal conductance, with plants from drier source sites performing better under the experimental drought. Seedlings from drier sites also had a lower C:N ratio, consistent with adaptation to more arid environments. Our study points to population‐level variation in seedling drought adaptation. Climate‐forward conservation strategies that conserve or leverage drought‐adaptive genetic resources from the species' threatened dry range edge could support climate change resilience in a future drier environment.

The iconic American chestnut (Castanea dentata) once spanned a large portion of eastern North America before its functional extinction in the early 20th century due primarily to non‐native fungal pathogens. The pronounced loss of this species likely resulted in an abrupt alteration of many ecological processes, including fire. The potential to resurrect this species through resistance breeding or other methods holds promise, but more information on the fire ecology of American chestnut may provide helpful information to assist restoration. Here we summarize the existing direct and indirect research on the fire history and fire ecology within the former range of American chestnut. We found multiple lines of evidence to suggest fire was frequent throughout much of its historical range. A broadscale analysis of historical fire frequency revealed that 88% of the American chestnut range had a mean fire return interval of 20 yr or less, corresponding to finer‐scale fire history and forest structure studies. In much of the historical range of American chestnut, the stand structure was much more open, fire scar studies of associated species were very frequent (mean fire return interval ranged between 1.9 and 19.8 yr), and, in many cases, charcoal abundance and American chestnut pollen were positively related. This evidence coupled with American chestnut’s suite of traits associated with tolerance of frequent fire, such as highly flammable litter, tall stature, rapid growth, and resprouting ability, reinforce concepts that fire was historically an important component of many woodlands and forests containing American chestnut. While these lines of evidence are strongly suggestive, we provide potential areas of further inquiry to expand and refine our understanding of American chestnut fire ecology.

Serotiny, a key fire‐adaptive trait, enables certain plants to retain seeds in closed cones until triggered by fire, thus facilitating post‐fire regeneration. Although serotiny has been observed in many species, the physiological and environmental mechanisms that regulate this trait remain poorly understood. In this study, we investigated the variation in serotiny level within Pinus yunnanensis, a pine species native to fire‐prone landscapes in southwestern China. Serotiny level varied significantly among populations and was significantly associated with environmental factors and cone physiological characteristics, including Bio2 (mean diurnal temperature range), Bio5 (maximum temperature of the warmest month), soil pH, total soil phosphorus, and cone resin content. Cone resin content exhibited the strongest direct positive effect on serotiny. Soil pH and phosphorus concentration negatively affected resin content in cones, thus indirectly reducing serotiny level. Bio2 enhanced serotiny indirectly by acidifying soil and promoting resin synthesis, while Bio5 decreased serotiny indirectly by increasing phosphorus availability and limiting resin accumulation. Recent fire activity and fire radiative power did not appear to have a significant effect on serotiny in P. yunnanensis. These findings enhance our understanding of how serotiny evolves under the combined pressures of climate and soil conditions in fire‐adapted ecosystems. This study investigates the intraspecific variation in serotiny level among three varieties of Pinus yunnanensis. Using field data and structural equation modeling, we found that cone resin content is the key physiological driver of serotiny, indirectly shaped by climate and soil factors. Our findings highlight the dominant role of long‐term environmental interactions over fire activity in shaping this fire‐adaptive trait.

A central goal in biology is to determine the ways in which evolution repeats itself. One of the most remarkable examples in nature of convergent evolutionary novelty is animal venom. Across diverse animal phyla, various specialized organs and anatomical structures have evolved from disparate developmental tissues to perform the same function, that is, produce and deliver a cocktail of potent molecules to subdue prey or predators. Venomous organisms therefore offer unique opportunities to investigate the evolutionary processes of convergence of key adaptive traits, and the molecular mechanisms underlying the emergence of novel genes, cells, and tissues. Indeed, some venomous species have already proven to be highly amenable as models for developmental studies, and recent work with venom gland organoids provides manipulatable systems for directly testing important evolutionary questions. Here, we provide a synthesis of the current knowledge that could serve as a starting point for the establishment of venom systems as new models for evolutionary and molecular biology. In particular, we highlight the potential of various venomous species for the study of cell differentiation and cell identity, and the regulatory dynamics of rapidly evolving, highly expressed, tissue-specific, gene paralogs. We hope that this review will encourage researchers to look beyond traditional study organisms and consider venom systems as useful tools to explore evolutionary novelties.

High-temperature stress affects crop yields worldwide. Identifying thermotolerant crop varieties and understanding the basis for this thermotolerance would have important implications for agriculture, especially in the face of climate change. Rice ( Oryza sativa ) varieties have evolved protective strategies to acclimate to high temperature, with different thermotolerance levels. In this review, we examine the morphological and molecular effects of heat on rice in different growth stages and plant organs, including roots, stems, leaves and flowers. We also explore the molecular and morphological differences among thermotolerant rice lines. In addition, some strategies are proposed to screen new rice varieties for thermotolerance, which will contribute to the improvement of rice for agricultural production in the future.

Plants have developed a suite of traits to survive the anaerobic and anoxic soil conditions in wetlands. Previous studies on wetland plant adaptive traits have focused mainly on physiological aspects under experimental conditions, or compared the trait expression of the local species pool. Thus, a comprehensive analysis of potential factors driving wetland plant adaptive traits under natural environmental conditions is still missing. In this study, we analysed three important wetland adaptive traits, that is root porosity, root/shoot ratio and underwater photosynthetic rate, to explore driving factors using a newly compiled dataset of wetland plants. Based on 21 studies at 38 sites across different biomes, we found that root porosity was affected by an interaction of temperature and hydrological regime; root:shoot ratio was affected by temperature, precipitation and habitat type; and underwater photosynthetic rate was affected by precipitation and life‐form. This suggests that a variety of driving mechanisms affect the expression of different adaptive traits. The quantitative relationships we observed between the adaptive traits and their driving factors will be a useful reference for future global methane and denitrification modelling studies. Our results also stress that besides the traditionally emphasized hydrological driving factors, other factors at several spatial scales should also be taken into consideration in the context of future functional wetland ecology. A free Plain Language Summary can be found within the Supporting Information of this article. 摘要 湿地植物具有能适应缺氧或厌氧湿地生境的特殊功能性状。 关于湿地植物适应性状的研究以前主要集中于实验条件下的生态生理学层面， 或者局限于区域尺度的物种间比较。 迄今仍然缺乏自然条件下的关于湿地植物适应性状驱动因子的综合性研究。 本研究基于新建立的包含来自 21 个研究结果的湿地植物性状数据集， 分析了湿地植物的三种重要适应性状（根孔隙度； 根/茎比例； 水下光合作用速率）的驱动因子。 研究结果表明：根孔隙度主要受温度和水文条件的交互影响； 根/茎比例主要受温度、降水及生境类型的驱动； 水下光合作用速率主要受降水及植物生活型的调节。 且不同的湿地适应性状受不同的驱动机制影响。 本研究所确立的湿地植物适应性状和环境因子之间的定量关系将为未来的全球甲烷模型、脱氮模型等提供重要理论依据。 本研究还提出， 未来的湿地功能生态学不应只局限于传统研究所强调的水文因素， 还应同时考虑不同空间尺度上植物适应性状的各类环境驱动因子。 A free Plain Language Summary can be found within the Supporting Information of this article.

Pulses are the main source of protein and minerals in the vegetarian diet. These are primarily cultivated on marginal lands with few inputs in several resource-poor countries of the world, including several in South Asia. Their cultivation in resource-scarce conditions exposes them to various abiotic and biotic stresses, leading to significant yield losses. Furthermore, climate change due to global warming has increased their vulnerability to emerging new insect pests and abiotic stresses that can become even more serious in the coming years. The changing climate scenario has made it more challenging to breed and develop climate-resilient smart pulses. Although pulses are climate smart, as they simultaneously adapt to and mitigate the effects of climate change, their narrow genetic diversity has always been a major constraint to their improvement for adaptability. However, existing genetic diversity still provides opportunities to exploit novel attributes for developing climate-resilient cultivars. The mining and exploitation of adaptive traits imparting tolerance/resistance to climate-smart pulses can be accelerated further by using cutting-edge approaches of biotechnology such as transgenics, genome editing, and epigenetics. This review discusses various classical and molecular approaches and strategies to exploit adaptive traits for breeding climate-smart pulses.

Background The initiation of growth cessation and dormancy represent critical life-history trade-offs between survival and growth and have important fitness effects in perennial plants. Such adaptive life-history traits often show strong local adaptation along environmental gradients but, despite their importance, the genetic architecture of these traits remains poorly understood. Results We integrate whole genome re-sequencing with environmental and phenotypic data from common garden experiments to investigate the genomic basis of local adaptation across a latitudinal gradient in European aspen ( Populus tremula ). A single genomic region containing the PtFT2 gene mediates local adaptation in the timing of bud set and explains 65% of the observed genetic variation in bud set. This locus is the likely target of a recent selective sweep that originated right before or during colonization of northern Scandinavia following the last glaciation. Field and greenhouse experiments confirm that variation in PtFT 2 gene expression affects the phenotypic variation in bud set that we observe in wild natural populations. Conclusions Our results reveal a major effect locus that determines the timing of bud set and that has facilitated rapid adaptation to shorter growing seasons and colder climates in European aspen. The discovery of a single locus explaining a substantial fraction of the variation in a key life-history trait is remarkable, given that such traits are generally considered to be highly polygenic. These findings provide a dramatic illustration of how loci of large-effect for adaptive traits can arise and be maintained over large geographical scales in natural populations.

Deploying well-adapted and ecologically appropriate plant materials is a core component of successful restoration projects. We have developed generalized provisional seed zones that can be applied to any plant species in the United States to help guide seed movement. These seed zones are based on the intersection of high-resolution climatic data for winter minimum temperature and aridity (as measured by annual heat : moisture index), each classified into discrete bands. This results in the delineation of 64 provisional seed zones for the continental United States. These zones represent areas of relative climatic similarity, and movement of seed within these zones should help to minimize maladaptation. Superimposing Omernik's level III ecoregions over these seed zones distinguishes areas that are similar climatically yet different ecologically. A quantitative comparison of provisional seed zones with level III ecoregions and provisional seed zones within ecoregions for three species showed that provisional seed zone within ecoregion often explained the greatest proportion of variation in a suite of traits potentially related to plant fitness. These provisional seed zones can be considered a starting point for guidelines for seed transfer, and should be utilized in conjunction with appropriate species-specific information as well as local knowledge of microsite differences.