02534nas a2200133   4500008004100000245007900041210006900120260001900189520207400208100002902282700002502311700002002336856004402356       2014                        eng d00aEvidence for selection on a CONSTANS-like gene between two red oak species0 aEvidence for selection on a CONSTANSlike gene between two red oa  cMarch 10, 20143 aBackground and Aims Hybridizing species such as oaks may provide a model to study the role of selection in speciation with gene flow. Discrete species' identities and different adaptations are maintained among closely related oak species despite recurrent gene flow. This is probably due to ecologically mediated selection at a few key genes or genomic regions. Neutrality tests can be applied to identify so-called outlier loci, which demonstrate locus-specific signatures of divergent selection and are candidate genes for further study.Methods Thirty-six genic microsatellite markers, some with putative functions in flowering time and drought tolerance, and eight non-genic microsatellite markers were screened in two population pairs (n = 160) of the interfertile species Quercus rubra and Q. ellipsoidalis, which are characterized by contrasting adaptations to drought. Putative outliers were then tested in additional population pairs from two different geographic regions (n = 159) to support further their potential role in adaptive divergence.Key Results A marker located in the coding sequence of a putative CONSTANS-like (COL) gene was repeatedly identified as under strong divergent selection across all three geographically disjunct population pairs. COL genes are involved in the photoperiodic control of growth and development and are implicated in the regulation of flowering time.Conclusions The location of the polymorphism in the Quercus COL gene and given the potential role of COL genes in adaptive divergence and reproductive isolation makes this a promising candidate speciation gene. Further investigation of the phenological characteristics of both species and flowering time pathway genes is suggested in order to elucidate the importance of phenology genes for the maintenance of species integrity. Next-generation sequencing in multiple population pairs in combination with high-density genetic linkage maps could reveal the genome-wide distribution of outlier genes and their potential role in reproductive isolation between these species.1 aLind-Riehl, Jennifer, F.1 aSullivan, Alexis, R.1 aGailing, Oliver  uhttps://quercus.myspecies.info/node/16302284nas a2200193   4500008004100000245014200041210006900183260001900252300001200271490000800283520159500291100003201886700002701918700002101945700002801966700002301994700002902017856004402046       2014                        eng d00aMorphological and physiological divergences within Quercus ilex support the existence of different ecotypes depending on climatic dryness0 aMorphological and physiological divergences within Quercus ilex   cAugust 1, 2014  a301-3130 v1143 aBackground and Aims Several studies show apparently contradictory findings about the functional convergence within the Mediterranean woody flora. In this context, this study evaluates the variability of functional traits within holm oak (Quercus ilex) to elucidate whether provenances corresponding to different morphotypes represent different ecotypes locally adapted to the prevaling stress levels.Methods Several morphological and physiological traits were measured at leaf and shoot levels in 9-year-old seedlings of seven Q. ilex provenances including all recognized morphotypes. Plants were grown in a common garden for 9 years under the same environmental conditions to avoid possible biases due to site-specific characteristics.Key Results Leaf morphometry clearly separates holm oak provenances into ‘ilex’ (more elongated leaves with low vein density) and ‘rotundifolia’ (short and rounded leaves with high vein density) morphotypes. Moreover, these morphotypes represent two consistent and very contrasting functional types in response to dry climates, mainly in terms of leaf area, major vein density, leaf specific conductivity, resistance to drought-induced cavitation and turgor loss point.Conclusions The ‘ilex’ and ‘rotundifolia’ morphotypes correspond to different ecotypes as inferred from their contrasting functional traits. To the best of our knowledge, this is the first time that the combined use of morphological and physiological traits has provided support for the concept of these two holm oak morphotypes being regarded as two different species.1 aPeguero-Pina, José, Javier1 aSancho-Knapik, Domingo1 aBarrón, Eduardo1 aCamarero, Julio, Jesús1 aVilagrosa, Alberto1 aGil-Pelegrín, Eustaquio  uhttps://quercus.myspecies.info/node/16802347nas a2200145   4500008004100000245014300041210006900184260002100253520181400274100001202088700001902100700001502119700002302134856004402157       2014                        eng d00aFactors affecting stress tolerance in recalcitrant embryonic axes from seeds of four Quercus (Fagaceae) species native to the USA or China0 aFactors affecting stress tolerance in recalcitrant embryonic axe  cOctober 17, 20143 aBackground and Aims Quercus species are often considered ‘foundation’ components of several temperate and/or subtropical forest ecosystems. However, the populations of some species are declining and there is considerable urgency to develop ex situ conservation strategies. In this study, the storage physiology of seeds within Quercus was explored in order to determine factors that affect survival during cryopreservation and to provide a quantitative assessment of seed recalcitrance to support future studies of this complex trait.Methods Water relations and survival of excised axes in response to water loss and cryo-exposure were compared for four Quercus species from subtropical China (Q. franchetii, Q. schottkyana) and temperate USA (Q. gambelii, Q. rubra).Key Results Seed tissues initially had high water contents and water potentials. Desiccation tolerance of the embryonic axis was not correlated with the post-shedding rainfall patterns where the samples originated. Instead, higher desiccation tolerance was observed in samples growing in areas with colder winters. Survival following cryo-exposure correlated with desiccation tolerance. Among species, plumule tissues were more sensitive than radicles to excision, desiccation and cryo-exposure, and this led to a higher proportion of abnormally developing embryos during recovery following stress.Conclusions Quercus species adapted to arid and semi-humid climates still produce recalcitrant seeds. The ability to avoid freezing rather than drought may be a more important selection factor to increase desiccation tolerance. Cryopreservation of recalcitrant germplasm from temperate species is currently feasible, whilst additional protective treatments are needed for ex situ conservation of Quercus from tropical and subtropical areas.1 aXia, Ke1 aHill, Lisa, M.1 aLi, De-Zhu1 aWalters, Christina  uhttps://quercus.myspecies.info/node/171