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Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis

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A special issue of Forests (ISSN 1999-4907). This special issue belongs to the section "Genetics and Molecular Biology".

Deadline for manuscript submissions: closed (31 May 2023) | Viewed by 23830

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Special Issue Editors

Dr. María-Dolores Rey

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Guest Editor

Agroforestry and Plant Biochemistry, Proteomics and Systems Biology, Department of Biochemistry and Molecular Biology, University of Cordoba, UCO-CeiA3, 14014 Cordoba, Spain
Interests: plant breeding; forest species; drought; Phytophthora cinnamomi; molecular markers; cytogenetics; genomics; transcriptomics
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Jesus V. Jorrin Novo

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Agroforestry and Plant Biochemistry, Proteomics and Systems Biology, Department of Biochemistry and Molecular Biology, University of Cordoba, UCO-CeiA3, 14014 Cordoba, Spain
Interests: forest species; biotic and abiotic stresses; molecular markers; omics approaches; systems biology
Special Issues, Collections and Topics in MDPI journals

Dr. María Ángeles Castillejo

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Guest Editor

Campus Rabanales, University of Cordoba, Cordoba, Spain
Interests: forest species; biotic and abiotic stresses; molecular markers; omics approaches; systems biology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Quercus (oak) species are dominant woody angiosperms in the Northern Hemisphere that are threatened by environmental cues and climate change conditions. Biotechnology should take a pivotal role in facing this problem and proposing sustainable management and conservation strategies. Tree breeding by exploiting natural biodiversity and selecting “elite” genotypes is the most unique plausible strategy. For that, it is necessary to investigate the biology of Quercus and to delve deep into the existing knowledge of genetic bases of phenotypes of interest, as well as select molecular markers. Acorn seeds could be considered as a source of nutritional compounds, justifying their use as secondary human foods. The existence of bioactive compounds in acorns would add value to this genus and would spark a change in its perception.

The current literature on these species (2910 references found at WoS in the last ten years) is diseminated and dispersed. The current Special Issue intends to bring together ongoing studies into the applications of morphological, ecophysiological, classical biochemistry and the most recent -omics approaches, as well as their integration in Systems Biology. The proposed editors group has 15 years of experience on the proposed topic, with 25 WoS publications during this period, and 5 nationally and internationally granted research projects.

Dr. María-Dolores Rey
Prof. Dr. Jesus V. Jorrin Novo
Dr. María Ángeles Castillejo
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Forests is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Quercus spp.
climate change
abiotic stress
biotic stress
biodiversity
breeding
oak decline
biotechnology
ecophysiology
omics approaches
molecular markers
systems biology

Published Papers (12 papers)

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Research

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19 pages, 9444 KiB

Open AccessArticle

Quercus petraea (Matt.) Liebl. from the Thayatal National Park in Austria: Selection of Potentially Drought-Tolerant Phenotypes

by Marcela van Loo, Roman Ufimov, Michael Grabner, Christian Übl, Andrea Watzinger, Florian Irauschek, Heino Konrad, Soňa Píšová and Carlos Trujillo-Moya

Forests 2023, 14(11), 2225; https://doi.org/10.3390/f14112225 - 11 Nov 2023

Viewed by 1010

Abstract

The increasing demand for climate-adapted seeds and planting material poses a challenge due to the limited availability, particularly for tree species such as oaks. National parks, known for their large-standing diversity and a wide range of habitats, can serve as valuable sources for identifying trees suitable for both the initiation of tree breeding and conservation strategies. This study aimed to identify valuable forest genetic resources of the Thayatal National Park in Austria by selecting potentially drought-tolerant phenotypes. For this purpose, we selected 404 mature trees of Quercus petraea (Matt.) Liebl. from eight populations growing on medium to dry sites in eight populations. Further, we characterized them for autochthony, genetic structure, genetic diversity using genetic markers (plastid- and nuclear-SSRs) and estimated their age. Finally, we applied wood core analysis to estimate tree response to historical drought events to identify the possible drought-tolerant phenotypes. The age of the trees ranged from 29 to 245 years (as of the year 2023). All Q. petraea trees were inhabiting a plastid haplotype 17a, autochthonous for this area. Nevertheless, the genetic structure estimated by ten nuSSRs revealed a pronounced structure in the dataset, largely caused by young trees exhibiting lower genetic diversity. A total of 85 elite potentially drought-tolerant trees were finally selected based on their morphological response (resistance, recovery ability, resilience, and relative resilience) to three historical drought events (1992–1994, 1947, 1917). The intrinsic water use efficiency and its difference (iWUE and DWiWUE), estimated by isotope analysis of δ13C of latewood in wet (1987) and dry (1994) years, did not correlate with any of the drought response traits (Rt, Rc, Rs, rRs). We discuss the further use of the selected oak trees for the establishment of seed stands and orchards to enhance seed production and the integration of other omics approaches, such as large-scale high-throughput plant phenotyping (HTPP) and transcriptomics, for in-depth analyses of drought tolerance of selected phenotypes. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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20 pages, 16523 KiB

Open AccessArticle

Spectral Analysis, Biocompounds, and Physiological Assessment of Cork Oak Leaves: Unveiling the Interaction with Phytophthora cinnamomi and Beyond

by Rui Guerra, Rosa Pires, António Brázio, Ana Margarida Cavaco, Gabriela Schütz and Ana Cristina Coelho

Forests 2023, 14(8), 1663; https://doi.org/10.3390/f14081663 - 17 Aug 2023

Viewed by 1022

Abstract

The cork oak tree (Quercus suber L.) symbolizes the Montado landscape in Portugal and is a central element in the country’s social and economic history. In recent decades, the loss of thousands of cork oaks has been reported, revealing the ongoing decline of these agroforestry ecosystems. This emblematic tree of the Mediterranean Basin is host to the soil-born root pathogen Phytophthora cinnamomi, an active cork oak decline driver. In this framework, the early diagnosis of trees infected by the oomycete by non-invasive methods should contribute to the sustainable management of cork oak ecosystems, which motivated this work. Gas exchange and visible/near-infrared (400–1100 nm) reflectance spectroscopy measurements were conducted on leaves of both control and P. cinnamomi inoculated plants. These measurements were taken at 63, 78, 91, 126, and 248 days after inoculation. Additionally, at the end of the experiment, biochemical assays of pigments, sugars, and starch were performed. The spectroscopic measurements proved effective in distinguishing between control and inoculated plants, while the standard gas exchange and biochemistry data did not exhibit clear differences between the groups. The spectral data were examined both daily and globally, utilizing the PARAFAC method applied to a three-way array of samples × wavelengths × days. The separation of the two plant groups was attributed to variations in water content (4v (O−H)); shifts in the spectra red edge; and structural modifications in the epidermal layer and leaves’ mesophyll. These spectral signatures can assist in the field identification of cork oaks that are interacting with P. cinnamomi. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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15 pages, 1651 KiB

Open AccessArticle

Beneficial Microorganisms and Water Stress Influence Quercus ilex Seedlings’ Response to Phytophthora cinnamomi Rands

by Roberto J. Cabrera-Puerto, Francisco J. Ruiz-Gómez and Rafael M. Navarro-Cerrillo

Forests 2023, 14(5), 870; https://doi.org/10.3390/f14050870 - 24 Apr 2023

Cited by 3 | Viewed by 1441

Abstract

Root rot affecting holm oak is a cause of high ecological and economic losses in the Iberian Peninsula, highlighting the relevance of developing disease control methods. The aim of this work was to assess the effect of a biological treatment composed of beneficial organisms (Trichoderma complex, T-complex) on holm oak seedlings infected by Phytophthora cinnamomi in two contrasted holm oak ecotypes, one considered highly susceptible (HU) and another considered tolerant to the pathogen (GR). For this purpose, a complete multifactorial test was carried out in a greenhouse, and seedlings were monitored for survival analysis and morphological and physiological attribute evaluation. Mortality began earlier in the susceptible (HU) than in the tolerant (GR) ecotype, and survival showed different trends due to the inoculation with beneficial microorganisms depending on the ecotype of the plants. The tolerant ecotype showed a high survival rate and better response to the treatment with beneficial microorganisms. GLM showed that the main reason for differences between treatments was ecotype, followed by T-complex and irrigation, and a weak interaction between ecotype and P. cinnamomi was found. The linear relationship between photosynthesis (A) and transpiration (Tr) showed an increase in the A/Tr rates for infected and inoculated plants under drought conditions for the GR ecotype. The tolerant ecotype was benefited more by the beneficial microorganism treatment. The understanding of the genetic diversity of Q. ilex and water stress influence on the efficacy of biological treatments against root rot provides useful information to develop environmentally friendly disease control methods to address the holm oak decline. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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15 pages, 2188 KiB

Open AccessArticle

Quercus suber Bark as a Sustainable Source of Value-Added Compounds: Experimental Studies with Cork By-Products

by Liliana Rego, Sandra Mota, Ana Torres, Cláudia Pinto, Sara Cravo, Joana Rocha e Silva, Ricardo N. M. J. Páscoa, Agostinho Almeida, Filipa Amaro, Paula Guedes Pinho, Honorina Cidade, José Paulo Silva, José Manuel Sousa Lobo and Isabel Filipa Almeida

Forests 2023, 14(3), 543; https://doi.org/10.3390/f14030543 - 9 Mar 2023

Cited by 3 | Viewed by 1918

Abstract

Quercus suber L. bark (cork) is a sustainable material due to its ability to regenerate. The aim of this work was to explore cork powders, by-products of the cork industry, as sustainable sources of value-added compounds. Two types of cork powder were studied: coarse (P0) and fine (P1). A broad physicochemical characterization was carried out, regarding particle size, color, moisture content, hygroscopicity, pH, heavy metal content, NIR spectra, and volatile compounds. DPPH scavenging activity and total phenolic content were also evaluated for an ethanolic P1 extract. For both powders, Hg, As, Cd and Pb contents were below the acceptable limits and volatile compounds commonly used as fragrances were found in their composition. P1 had a smaller and more homogenous particle size, lighter brownish color, lower pH value, and lower moisture content than P0, and therefore appears to be more suitable for industrial application. P1 ethanolic extract also showed a high scavenging activity and a content of phenolic compounds of 50.46 ± 0.63 mg (as gallic acid equivalents) per g of extract. In conclusion, P1 cork powder seems to be a promising source of upcycled ingredients, such as fragrances and antioxidants, for the pharmaceutical, nutraceutical, and cosmetic industries. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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13 pages, 3160 KiB

Open AccessArticle

Changes in Reserve Materials Deposited in Cotyledons of Pedunculate Oak (Quercus robur L.) Seeds during 18 Months of Storage

by Mikołaj Krzysztof Wawrzyniak, Ewa Marzena Kalemba, Tomasz Piotr Wyka and Paweł Chmielarz

Forests 2022, 13(12), 2142; https://doi.org/10.3390/f13122142 - 14 Dec 2022

Cited by 2 | Viewed by 1247

Abstract

Pedunculate oak (Quercus robur L.) produces desiccation-sensitive seeds, the long-term storage of which is limited. We investigated the effectiveness of using a slightly lowered storage temperature (−5 °C) in combination with slight dehydration of acorns (38% MC) for improving seed viability during 18 months of storage. To this end, we performed a factorial experiment using storage temperatures of −5 °C and −3 °C combined with 38% and 40% seed MC and subsampled the acorns at 4-month intervals over 18 months. The modified regime of −5 °C combined with 38% MC resulted in increased germination and emergence rates but only when seeds were stored for 12 months. It also restricted seed biomass loss. Starch depletion was recorded on consecutive sampling dates, showing little dependence on storage conditions. At −5 °C at both MC, it was accompanied by an accumulation of soluble carbohydrates. Fat reserves also decreased under all storage conditions, but the slowest decrease was at −5 °C and 38% MC. We conclude that storing acorns in a slightly dehydrated state (38% MC) at −5 °C produced a transient improvement in seed viability and that the observed increase in soluble carbohydrates may indicate initiation of prosurvival mechanisms, such as osmo- and cryoprotection. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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13 pages, 1861 KiB

Open AccessArticle

Population Study Reveals Genetic Variation and Introgression of Four Deciduous Oaks at the Junction between Taihang Mountain and Yanshan Mountain

by Ziqi Pei, Qinsong Yang, Xining Chen, Yu Zong, Jinjin Li, Xiong Yang, Chenrui Huo, Yixin Chen, Na Luo, Jialu Kang, Xiaoqian Meng, Yining Li, Huirong Zhou, Jiaxi Wang, Yong Liu and Guolei Li

Forests 2022, 13(10), 1647; https://doi.org/10.3390/f13101647 - 8 Oct 2022

Cited by 2 | Viewed by 1397

Abstract

Oaks (Quercus spp.) are considered model plants for studying plant evolution and natural gene introgression. Beijing area is at the junction between Taihang Mountain and Yanshan Mountain, and it is an overlapping distribution area of several deciduous oaks native to China. Interspecific hybridization often occurs in sympatric sibling species, resulting in blurred interspecific boundaries and hindering the development of breeding. To have better improvement and protection of these oaks, it is urgently necessary to evaluate the genetic diversity and population structure of these oak species. In this study, we collected eleven populations of four oak species (Q. variabilis, Q. mongolica, Q. dentata and Q. aliena) in the Beijing area. By using the polymorphic SSR markers, we analyzed the genetic variation of the collected 400 individuals, investigated the population structure, and found gene introgression events. Q. variabilis had a clearer genetic background as compared to the other three species. Q. mongolica had a more frequent gene introgression with Q. dentata and Q. aliena. Our data reveal the introgression and genetic diversity of the four oak species native to the Beijing area, laying the foundation for conducting an oak germplasm nursery with a clear genetic background for protection and further improvement. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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15 pages, 3748 KiB

Open AccessArticle

Assessing Leaf Morphometric Symmetry of Four Chinese Quercus Species in a Mixed Forest

by Xuan Li, Xiaojing Yu, Jiefan Huang, Yousry A. EI-Kassaby and Yanming Fang

Forests 2022, 13(10), 1635; https://doi.org/10.3390/f13101635 - 6 Oct 2022

Cited by 2 | Viewed by 1481

Abstract

(1) Background: Oaks have achieved notoriety for sufficient levels of sympatric species richness allowing hybridization, thus generating substantial phenotypic variation. Leaf fluctuation asymmetry is an important attribute, as it reflects not only genetic variability but also species buffering capacity. (2) Methods: We investigated the phenotypic diversity of four-oak species (Quercus acutissima, Q. variabilis, Q. fabri, and Q. serrata var. brevipetiolata) using leaf geometric morphometric analysis. Eight leaf morphological indicators (length, width, perimeter, area, left and right areas, areal ratio, and normalized symmetry index) were used to determine the hybridization level, whereas bilateral symmetry indicators were used to assess species environmental adaptation; (3) Results: Phenotypic variation ranged from 1.54 to 29.35 folds and significantly diverged among the studied species. Taxonomically species in Section Quercus (Q. fabri and Q. serrata var. brevipetiolata) are lower than those in Section Cerris (Q. acutissima and Q. variabilis) with good bilateral symmetry. The bilateral symmetry index of Q. variabilis had a larger range of variation, indicating better environmental adaptability; (4) Conclusions: We presume that species in Section Quercus with less leaf fluctuation asymmetry have a high level of genetic heterozygosity; however, this assumption requires further verification. The observed phenotypic diversity reflects a combination of environmental and genetic factors. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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14 pages, 2407 KiB

Open AccessArticle

Exploring the Use of Solid Biofertilisers to Mitigate the Effects of Phytophthora Oak Root Disease

by Aida López-Sánchez, Miquel Capó, Jesús Rodríguez-Calcerrada, Marta Peláez, Alejandro Solla, Juan A. Martín and Ramón Perea

Forests 2022, 13(10), 1558; https://doi.org/10.3390/f13101558 - 24 Sep 2022

Cited by 1 | Viewed by 1410

Abstract

Oak forests are facing multiple threats due to global change, with the introduction and expansion of invasive pathogens as one of the most detrimental. Here, we evaluated the use of soil biological fertiliser Biohumin^® to improve the response of Quercus ilex L. to the soil-borne pathogen Phytophthora cinnamomi Rands by using one-year-old seedlings fertilised at 0, 12.5, and 25% concentrations of Biohumin^® (v/v). Our hypothesis was that plant vigour and response to the pathogen would improve with Biohumin^®. The effects of soil infestation and fertilisation were tested by assessing plant survival, growth, and physiology. The soil infested with P. cinnamomi negatively affected all the studied traits. We observed that a moderate concentration of Biohumin^® (12.5%) increased plant survival. However, a high concentration (25%) reduced the survival compared with the control, probably as a result of the stress caused by both biotic (infection) and abiotic (soil toxicity) factors. Biohumin^® at the highest concentration reduced the plant height-to-stem diameter ratio (H/D) and negatively affected plant biomass and physiological activity. Combined biofertilisation and infection induced synergistic negative effects in the leaf water potential compared with infection and fertilisation applied alone. A higher concentration of Biohumin^® may favour pathogens more than plants. Further studies should explore the causes of the negative effect of the high concentration of Biohumin^® observed here and evaluate if lower concentrations may benefit plant survival and physiology against soil pathogens. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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19 pages, 1387 KiB

Open AccessArticle

Untargeted MS-Based Metabolomics Analysis of the Responses to Drought Stress in Quercus ilex L. Leaf Seedlings and the Identification of Putative Compounds Related to Tolerance

by Marta Tienda-Parrilla, Cristina López-Hidalgo, Victor M. Guerrero-Sanchez, Álvaro Infantes-González, Rocío Valderrama-Fernández, María-Ángeles Castillejo, Jesús V. Jorrín-Novo and María-Dolores Rey

Forests 2022, 13(4), 551; https://doi.org/10.3390/f13040551 - 31 Mar 2022

Cited by 13 | Viewed by 2871

Abstract

The effect and responses to drought stress were analyzed in Quercus ilex L. seedlings using a nontargeted metabolomic approach, implementing the approaches of previous studies in which other -omics platforms, transcriptomics, and proteomics were employed. This work aimed to characterize the Q. ilex leaf metabolome, determining possible mechanisms and molecular markers of drought tolerance and identifying putative bioactive compounds. Six-month-old seedling leaves subjected to drought stress imposed by water withholding under high-temperature and irradiance conditions were collected when leaf fluorescence decreased by 20% (day 17) and 45% (day 24) relative to irrigated seedlings. A total of 3934 compounds were resolved, with 616 being variable and 342 identified, which belonged to five chemical families. Out of the identified compounds, 33 were variable, mostly corresponding to amino acids, carboxylic acids, benzenoids, flavonoids and isoprenoids. Epigallocatechin, ellagic acid, pulegone, indole-3-acrylic acid and dihydrozeatin-O-glucoside were up-accumulated under drought conditions at both sampling times. An integrated multi-omics analysis of phenolic compounds and related enzymes was performed, revealing that some enzymes involved in the flavonoid pathways (chalcone synthase, anthocyanidin synthase and anthocyanidin reductase) were up-accumulated at day 24 in non-irrigated seedlings. Some putative markers of tolerance to drought in Q. ilex are proposed for assisting breeding programs based on the selection of elite genotypes. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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13 pages, 2731 KiB

Open AccessArticle

Kinship Analysis and Pedigree Reconstruction of a Natural Regenerated Cork Oak (Quercus suber) Population

by Bruna Mendes, Teresa Sampaio, Marta A. Antunes, Hugo Magalhães, Filipe Costa e Silva, Carla Borges, Fernanda Simões, Ana Usié, Maria Helena Almeida and António Marcos Ramos

Forests 2022, 13(2), 226; https://doi.org/10.3390/f13020226 - 2 Feb 2022

Cited by 3 | Viewed by 1857

Abstract

Cork oak (Quercus suber L.) is a valuable forest species in the western Mediterranean Basin due to its ecological value and the production of cork (a renewable natural material). Cork quality depends on the genetic background and cork oak environment, which has long been recognized. As no cork oak genetic trials with pedigree information were available, the inference of the genetic relatedness between individuals from molecular markers can potentially be applied to natural populations. This work aimed to investigate the potential of performing kinship prediction and pedigree reconstruction by SNP genotyping a natural cork oak population. A total of 494 trees located in Portugal were genotyped with 8K SNPs. The raw SNP set was filtered differently, producing four SNP sets that were further filtered by missing data, genotype frequency, and minor allele frequency. For each set, an identity by descent (IBD) matrix was generated to perform the relationship prediction, revealing from 22,114 to 23,859 relationships. Familial categories from the first to the third degree were able to be assigned. The feasibility of SNP genotyping for future studies on the kinship analysis and pedigree reconstruction of cork oak populations was demonstrated. The information produced may be used in further breeding and conservation programs for cork oak. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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16 pages, 1812 KiB

Open AccessArticle

Genetic Differentiation and Demographic History of Three Cerris Oak Species in China Based on Nuclear Microsatellite Makers

by Xiao-Dan Chen, Xiao Zhang, Hao Zhang, Tao Zhou, Yue-Mei Zhao, Jia Yang and Gui-Fang Zhao

Forests 2021, 12(9), 1164; https://doi.org/10.3390/f12091164 - 27 Aug 2021

Cited by 4 | Viewed by 2021

Abstract

Knowledge of interspecific divergence and population expansions/contractions of dominant forest trees in response to geological events and climatic oscillations is of major importance to understand their evolution and demography. However, the interspecific patterns of genetic differentiation and spatiotemporal population dynamics of three deciduous Cerris oak species (Q. acutissima, Q. variabilis and Q. chenii) that are widely distributed in China remain poorly understood. In this study, we genotyped 16 nuclear loci in 759 individuals sampled from 44 natural populations of these three sibling species to evaluate the plausible demographical scenarios of the closely related species. We also tested the hypothesis that macro- and microevolutionary processes of the three species had been triggered and molded by Miocene–Pliocene geological events and Quaternary climatic change. The Bayesian cluster analysis showed that Q. acutissima and Q. chenii were clustered in the same group, whereas Q. variabilis formed a different genetic cluster. An approximate Bayesian computation (ABC) analyses suggested that Q. variabilis and Q. acutissima diverged from their most common ancestor around 19.84 Ma, and subsequently Q. chenii diverged from Q. acutissima at about 9.6 Ma, which was significantly associated with the episodes of the Qinghai–Tibetan Plateau (QTP). In addition, ecological niche modeling and population history analysis showed that these three Cerris oak species repeatedly underwent considerable ‘expansion–contraction’ during the interglacial and glacial periods of the Pleistocene, although they have varying degrees of tolerance for the climatic change. Overall, these findings indicated geological and climatic changes during the Miocene–Pliocene and Pleistocene as causes of species divergence and range shifts of dominant tree species in the subtropical and warm temperature areas in China. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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Review

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14 pages, 2227 KiB

Open AccessEditor’s ChoiceReview

An Overview of Oak Species in Pakistan: Past, Present, and Future Research Perspectives

by Noor Muhammad, María Ángeles Castillejo, Maria-Dolores Rey and Jesús V. Jorrín-Novo

Forests 2023, 14(4), 777; https://doi.org/10.3390/f14040777 - 10 Apr 2023

Cited by 2 | Viewed by 4507

Abstract

Quercus spp. have formed broad-leaved evergreen forests in the Hindu Kush and Himalayan regions of Pakistan. Seven species of the genus Quercus (Q. baloot Griff., Q. dilatata Royle., Q. glauca Thunb., Q. incana Roxb., Q. robur Linn., Q. semecarpifolia Smith., and Q. leucotrichophora A. Camus.) have been identified. These species have received little attention compared with other economically valuable plant species in Pakistan, which has been mainly linked to traditional medicine and the identification of phytonutrients to evaluate their bioactivities and toxicological effects. Quercus spp. are promising for commercial applications, so government policy should encourage their management and conservation. However, they are currently threatened by severe human activities and climate change. The goal of this review is to highlight the relevance of these forgotten species, describing overall aspects related to their distribution, morphology, traditional uses, phytochemical constituents, and threats. To date, no proper and comprehensive molecular studies on the populations of these species found in Pakistan have been conducted, which is a critical gap as molecular studies are essential for conservation and management strategies. Finally, we discuss future directions in molecular approaches for Quercus that follow the strategies that are being used for other species of the genus Quercus that are not found in Pakistan. Full article

(This article belongs to the Special Issue Quercus Research for Improvement and Protection: From Field and Greenhouse Experiments to Biotechnology and Molecular Analysis)

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