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1.
BMC Ecol Evol ; 21(1): 50, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33784979

RESUMO

BACKGROUND: Comparative phylogeographic studies on rainforest species that are widespread in Central Africa often reveal genetic discontinuities within and between biogeographic regions, indicating (historical) barriers to gene flow, possibly due to repeated and/or long-lasting population fragmentation during glacial periods according to the forest refuge hypothesis. The impact of forest fragmentation seems to be modulated by the ecological amplitude and dispersal capacities of each species, resulting in different demographic histories. Moreover, while multiple studies investigated the western part of Central Africa (Lower Guinea), few have sufficiently sampled the heart of the Congo Basin (Congolia). In this study, we look for genetic discontinuities between populations of the widespread tropical tree Scorodophloeus zenkeri Harms (Fabaceae, Detarioideae) in Central Africa. Additionally, we characterize genetic diversity, selfing rate and fine-scale spatial genetic structure within populations to estimate the gene dispersal capacity of the species. RESULTS: Clear intraspecific genetic discontinuities occur throughout the species' distribution range, with two genetic clusters in Congolia and four in Lower Guinea, and highest differentiation occurring between these bioregions. Genetic diversity is higher in Lower Guinea than Congolia. A spatial genetic structure characteristic of isolation by distance occurs within the genetic clusters. This allowed us to estimate gene dispersal distances (σg) for this outcrossing species with ballistic seed dispersal, which range between 100 and 250 m in areas where S. zenkeri occurs in high densities, and are in the low range of σg values compared to other tropical trees. Gene dispersal distances are larger in low density populations, probably due to extensive pollen dispersal capacity. CONCLUSIONS: Fragmentation of S. zenkeri populations seems to have occurred not only in Lower Guinea but also in the Congo Basin, though not necessarily according to previously postulated forest refuge areas. The lower genetic diversity in Congolia compared to Lower Guinea parallels the known gradient of species diversity, possibly reflecting a stronger impact of past climate changes on the forest cover in Congolia. Despite its bisexual flowers, S. zenkeri appears to be mostly outcrossing. The limited dispersal observed in this species implies that genetic discontinuities resulting from past forest fragmentation can persist for a long time before being erased by gene flow.


Assuntos
Fabaceae , Dispersão de Sementes , África Central , Congo , Florestas , Variação Genética , Filogeografia , Árvores/genética
2.
Nat Commun ; 12(1): 1169, 2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33608515

RESUMO

Assisted gene flow between populations has been proposed as an adaptive forest management strategy that could contribute to the sequestration of carbon. Here we provide an assessment of the mitigation potential of assisted gene flow in 46 populations of the widespread boreal conifer Picea mariana, grown in two 42-year-old common garden experiments and established in contrasting Canadian boreal regions. We use a dendroecological approach taking into account phylogeographic structure to retrospectively analyse population phenotypic variability in annual aboveground net primary productivity (NPP). We compare population NPP phenotypes to detect signals of adaptive variation and/or the presence of phenotypic clines across tree lifespans, and assess genotype-by-environment interactions by evaluating climate and NPP relationships. Our results show a positive effect of assisted gene flow for a period of approximately 15 years following planting, after which there was little to no effect. Although not long lasting, well-informed assisted gene flow could accelerate the transition from carbon source to carbon sink after disturbance.


Assuntos
Carbono/metabolismo , Fluxo Gênico , Picea/genética , Picea/metabolismo , Taiga , Canadá , Sequestro de Carbono , Clima , Mudança Climática , Geografia , Estudos Retrospectivos , Temperatura , Traqueófitas , Árvores/genética
3.
Mol Ecol ; 30(5): 1108-1109, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33547830
4.
DNA Cell Biol ; 40(4): 606-617, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33493084

RESUMO

DNA methylation is an important epigenetic regulator of gene expression. Application of 5-azacytidine (a methylation inhibitor) significantly promoted bud sprouting rate and the elongation of branches and leaves in "Luhehong" and "Fengdanbai." In total, 11,166 and 11,443 fragments were obtained by methylation-sensitive amplified polymorphism (MSAP) analysis during chilling-induced dormancy release in the two varieties, respectively. Total methylation levels were high in dormant buds, mainly for hemimethylation, which were slowly increased by short-term chilling (7 days) and decreased by long-term chilling. Compared with 0 day, the ratio of the methylation downregulated group increased during dormancy release, whereas that of the upregulated group declined gradually. These variations were consistent with the dynamic expressions of DNA methyltransferase/demethylase genes and their enzyme activity changes. In total, 13 polymorphic MSAP fragments were similar to known proteins (E-value <1e-5), and their methylation statuses were consistent with their expression patterns. The expression change of PsCWH, encoding cell wall hydrolase, might be due to DNA methylation ratios of CpG sites identified by bisulfite sequencing. These results indicated that chilling accumulation promoted bud dormancy release and sprouting through DNA methylation modification of specific genes. This study would provide new insights into the molecular mechanism underlying dormancy release in tree peony.


Assuntos
Epigênese Genética/genética , Paeonia/genética , Dormência de Plantas/genética , Azacitidina/farmacologia , China , Biologia Computacional/métodos , DNA/genética , Metilação de DNA/genética , Epigenômica/métodos , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Paeonia/metabolismo , Dormência de Plantas/fisiologia , Árvores/genética , Árvores/metabolismo
5.
Am J Bot ; 108(1): 102-112, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33512710

RESUMO

PREMISE: Persistence of tree populations in the face of global change relies on their capacity to respond to biotic and abiotic stressors through plastic or adaptive changes. Genetic adaptation will depend on the additive genetic variation within populations and the heritability of traits related to stress tolerance. Because traits can be genetically linked, selective pressure acting on one trait may lead to correlated responses in other traits. METHODS: To test direct and correlated responses to selection for growth and drought tolerance in Pinus halepensis, we selected trees in a parental population for higher growth and greater water-use efficiency (WUE) and compared their offspring with the offspring of random trees from the parental population in two contrasting common gardens. We estimated direct responses to selection for growth and WUE and correlated responses for growth and tolerance to abiotic and biotic stressors. RESULTS: We found a strong response to selection and high realized heritability for WUE, but no response to selection for growth. Correlated responses to selection in other life-history traits were not significant, except for concentration of some chemical defenses, which was greater in the offspring of mother trees selected for growth than in the offspring of unselected control trees. CONCLUSIONS: The empirical evidence of direct responses to selection for high WUE suggests that P. halepensis has the potential to evolve in response to increasing drought stress. Contrary to expectations, the results are not conclusive of a potential negative impact of WUE and growth selection on other key life-history traits.


Assuntos
Pinus , Água , Secas , Fenótipo , Pinus/genética , Árvores/genética
6.
Curr Opin Plant Biol ; 59: 101995, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33444911

RESUMO

The regulation of bloom time in deciduous fruit trees is an area of increasing interest due to the negative impact of climate change on fruit production. Although flower development has been well-studied in model species, there are many knowledge gaps about this process in perennial fruit trees, whose floral development spans the four seasons and includes many temperature-driven transitions. To develop solutions for minimizing crop loss, a comprehensive research strategy is needed to understand flower development and bloom time in deciduous fruit trees. This approach must incorporate genetic, physiological, and phenological strategies which include morphological and molecular analyses. Here, we describe key floral development events for rosaceae family fruit trees, highlight recent molecular and genetic discoveries, and discuss future directions for this field.


Assuntos
Frutas , Árvores , Biologia , Flores/genética , Frutas/genética , Reprodução , Estações do Ano , Árvores/genética
7.
Glob Chang Biol ; 27(6): 1181-1195, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33345407

RESUMO

The ongoing increase in global temperature affects biodiversity, especially in mountain regions where climate change is exacerbated. As sessile, long-lived organisms, trees are especially challenged in terms of adapting to rapid climate change. Here, we show that low rates of allele frequency shifts in Swiss stone pine (Pinus cembra) occurring near the treeline result in high genomic vulnerability to future climate warming, presumably due to the species' long generation time. Using exome sequencing data from adult and juvenile cohorts in the Swiss Alps, we found an average rate of allele frequency shift of 1.23 × 10-2 /generation (i.e. 40 years) at presumably neutral loci, with similar rates for putatively adaptive loci associated with temperature (0.96 × 10-2 /generation) and precipitation (0.91 × 10-2 /generation). These recent shifts were corroborated by forward-in-time simulations at neutral and adaptive loci. Additionally, in juvenile trees at the colonisation front we detected alleles putatively beneficial under a future warmer and drier climate. Notably, the observed past rate of allele frequency shift in temperature-associated loci was decidedly lower than the estimated average rate of 6.29 × 10-2 /generation needed to match a moderate future climate scenario (RCP4.5). Our findings suggest that species with long generation times may have difficulty keeping up with the rapid climate change occurring in high mountain areas and thus are prone to local extinction in their current main elevation range.


Assuntos
Pinus , Árvores , Biodiversidade , Mudança Climática , Genômica , Árvores/genética
8.
PLoS One ; 15(8): e0230404, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866150

RESUMO

High-throughput SNP genotyping has become a precondition to move to higher precision and wider genome coverage genetic analysis of natural and breeding populations of non-model species. We developed a 44,318 annotated SNP catalog for Araucaria angustifolia, a grandiose subtropical conifer tree, one of the only two native Brazilian gymnosperms, critically endangered due to its valuable wood and seeds. Following transcriptome assembly and annotation, SNPs were discovered from RNA-seq and pooled RAD-seq data. From the SNP catalog, an Axiom® SNP array with 3,038 validated SNPs was developed and used to provide a comprehensive look at the genetic diversity and structure of 15 populations across the natural range of the species. RNA-seq was a far superior source of SNPs when compared to RAD-seq in terms of conversion rate to polymorphic markers on the array, likely due to the more efficient complexity reduction of the huge conifer genome. By matching microsatellite and SNP data on the same set of A. angustifolia individuals, we show that SNPs reflect more precisely the actual genome-wide patterns of genetic diversity and structure, challenging previous microsatellite-based assessments. Moreover, SNPs corroborated the known major north-south genetic cline, but allowed a more accurate attribution to regional versus among-population differentiation, indicating the potential to select ancestry-informative markers. The availability of a public, user-friendly 3K SNP array for A. angustifolia and a catalog of 44,318 SNPs predicted to provide ~29,000 informative SNPs across ~20,000 loci across the genome, will allow tackling still unsettled questions on its evolutionary history, toward a more comprehensive picture of the origin, past dynamics and future trend of the species' genetic resources. Additionally, but not less importantly, the SNP array described, unlocks the potential to adopt genomic prediction methods to accelerate the still very timid efforts of systematic tree breeding of A. angustifolia.


Assuntos
Araucaria/genética , Brasil , Genoma de Planta/genética , Genômica/métodos , Genótipo , Repetições de Microssatélites/genética , Polimorfismo de Nucleotídeo Único/genética , Traqueófitas/genética , Transcriptoma/genética , Árvores/genética
9.
Trends Plant Sci ; 25(9): 846-849, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32732116

RESUMO

Separating out the different effects of ageing on long-lived trees remains challenging. Herein current approaches used to explore senescence in millennial trees are highlighted. Molecular and biochemical analyses of the vascular cambium provide novel insight into the extent to which millennial trees can withstand the wear and tear of ageing.


Assuntos
Câmbio , Árvores , Árvores/genética
10.
Am J Bot ; 107(7): 1041-1053, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32638366

RESUMO

PREMISE: A good understanding of genetic variation and gene dispersal in tree populations is crucial for their sustainable management, particularly in a context of rapid environmental changes. West African Sudanian savannahs are being fragmented and degraded, partly due to expansion of crop cultivation and monocultures that reduce tree density and may impact pollinators. The population dynamics of important indigenous trees could also be affected. We investigated the influence of habitat fragmentation on patterns of genetic diversity and gene dispersal of a key Sudanian agroforestry tree species, Parkia biglobosa. METHODS: Using 10 highly polymorphic nuclear microsatellites, we genotyped 2475 samples from reproductive trees, seedlings, and embryos in four tree populations presenting different levels of habitat fragmentation. RESULTS: Parkia biglobosa presented similar high genetic diversity across the four populations studied. Genetic diversity and inbreeding were similar between adults and embryo cohorts. In all four populations, the selfing rate was less than 1%. The effective number of pollen donors per tree was high (NEP ~ 18-22), as was the pollen immigration rate (from 34 to 74%). Pollen dispersal was characterized by a fat-tailed distribution with mean estimates exceeding 200 m. In three populations, stem diameter had a pronounced effect on male reproductive success. Here, the highest male reproductive success was observed in trees with a diameter at breast height between 60 and 75 cm. CONCLUSIONS: At the scale analyzed, fragmentation does not seem to pose limitations to gene flow in any of the sites investigated, regardless of the landscape configuration associated with the different tree stands. The study provides useful insights on the reproductive biology of an important tree species in the West African savannahs.


Assuntos
Ecossistema , Fluxo Gênico , Variação Genética , Genética Populacional , Endogamia , Repetições de Microssatélites/genética , Árvores/genética
11.
Yi Chuan ; 42(7): 657-668, 2020 Jul 20.
Artigo em Chinês | MEDLINE | ID: mdl-32694105

RESUMO

The CRISPR/Cas9 system, which can induce precise modifications at a target gene, has been recognized as the most promising gene editing technology, and has played an important role in precision crop breeding. It also provides a new strategy for fundamental researches and molecular breeding of forest trees. Recently, CRISPR/Cas9-mediated gene editing has been applied more extensively in tree genetic studies. It has not only succeeded in developing new drought- resistance or disease-resistant cultivars, but also shows a great potential in regulating lignin biosynthesis and shortening the breeding cycle of forest trees. In this review, we summarize the application and advance of CRISPR/Cas9 in gene function identification and genetic improvement of forest plants. We also discuss the related problems and future perspectives. This review aims to provide a useful reference for tree functional genomics and genetic engineering breeding.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Árvores , Sistemas CRISPR-Cas/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Plantas/genética , Árvores/genética
12.
Nat Commun ; 11(1): 3719, 2020 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-32709943

RESUMO

Wild teas are valuable genetic resources for studying domestication and breeding. Here we report the assembly of a high-quality chromosome-scale reference genome for an ancient tea tree. The further RNA sequencing of 217 diverse tea accessions clarifies the pedigree of tea cultivars and reveals key contributors in the breeding of Chinese tea. Candidate genes associated with flavonoid biosynthesis are identified by genome-wide association study. Specifically, diverse allelic function of CsANR, CsF3'5'H and CsMYB5 is verified by transient overexpression and enzymatic assays, providing comprehensive insights into the biosynthesis of catechins, the most important bioactive compounds in tea plants. The inconspicuous differentiation between ancient trees and cultivars at both genetic and metabolic levels implies that tea may not have undergone long-term artificial directional selection in terms of flavor-related metabolites. These genomic resources provide evolutionary insight into tea plants and lay the foundation for better understanding the biosynthesis of beneficial natural compounds.


Assuntos
Variação Genética , Genoma de Planta , Melaleuca/genética , Linhagem , Árvores/genética , Alelos , Vias Biossintéticas/genética , Camellia sinensis/genética , Catequina/metabolismo , China , Domesticação , Evolução Molecular , Ácido Gálico/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Estudo de Associação Genômica Ampla , Genômica , Análise de Sequência de RNA , Óleo de Melaleuca
13.
PLoS One ; 15(6): e0234315, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32516353

RESUMO

Stable carbon and oxygen isotope ratios of raw pollen sampled from nine abundant tree species growing in natural habitats of central and northern Europe were investigated to understand the intra- and inter-specific variability of pollen-isotope values. All species yielded specific δ13Cpollen and δ18Opollen values and patterns, which can be ascribed to their physiology and habitat preferences. Broad-leaved trees flowering early in the year before leaf proliferation (Alnus glutinosa and Corylus avellana) exhibited on average 2.6‰ lower δ13Cpollen and 3.1‰ lower δ18Opollen values than broad-leaved and coniferous trees flowering during mid and late spring (Acer pseudoplatanus, Betula pendula, Carpinus betulus, Fagus sylvatica, Picea abies, Pinus sylvestris and Quercus robur). Mean species-specific δ13Cpollen values did not change markedly over time, whereas δ18Opollen values of two consecutive years were often statistically distinct. An intra-annual analysis of B. pendula and P. sylvestris pollen revealed increasing δ18Opollen values during the final weeks of pollen development. However, the δ13Cpollen values remained consistent throughout the pollen-maturation process. Detailed intra-individual analysis yielded circumferential and height-dependent variations within carbon and oxygen pollen-isotopes and the sampling position on a tree accounted for differences of up to 3.5‰ for δ13Cpollen and 2.1‰ for δ18Opollen. A comparison of isotope ranges from different geographic settings revealed gradients between maritime and continental as well as between high and low altitudinal study sites. The results of stepwise regression analysis demonstrated, that carbon and oxygen pollen-isotopes also reflect local non-climate environmental conditions. A detailed understanding of isotope patterns and ranges in modern pollen is necessary to enhance the accuracy of palaeoclimate investigations on δ13C and δ18O of fossil pollen. Furthermore, pollen-isotope values are species-specific and the analysis of species growing during different phenophases may be valuable for palaeoweather reconstructions of different seasons.


Assuntos
Carbono/metabolismo , Oxigênio/metabolismo , Pólen/metabolismo , Betulaceae/crescimento & desenvolvimento , Isótopos de Carbono/análise , Clima , Ecossistema , Fagaceae/crescimento & desenvolvimento , Isótopos de Oxigênio/análise , Pinaceae/crescimento & desenvolvimento , Pólen/genética , Sapindaceae/crescimento & desenvolvimento , Estações do Ano , Especificidade da Espécie , Árvores/genética , Árvores/crescimento & desenvolvimento , Árvores/metabolismo
14.
PLoS One ; 15(6): e0233800, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497070

RESUMO

Several studies suggest the relation of DNA methylation to diseases in humans and important phenotypes in plants drawing attention to this epigenetic mark as an important source of variability. In the last decades, several methodologies were developed to assess the methylation state of a genome. However, there is still a lack of affordable and precise methods for genome wide analysis in large sample size studies. Methyl sensitive double digestion MS-DArT sequencing method emerges as a promising alternative for methylation profiling. We developed a computational pipeline for the identification of DNA methylation using MS-DArT-seq data and carried out a pilot study using the Eucalyptus grandis tree sequenced for the species reference genome. Using a statistic framework as in differential expression analysis, 72,515 genomic sites were investigated and 5,846 methylated sites identified, several tissue specific, distributed along the species 11 chromosomes. We highlight a bias towards identification of DNA methylation in genic regions and the identification of 2,783 genes and 842 transposons containing methylated sites. Comparison with WGBS, DNA sequencing after treatment with bisulfite, data demonstrated a precision rate higher than 95% for our approach. The availability of a reference genome is useful for determining the genomic context of methylated sites but not imperative, making this approach suitable for any species. Our approach provides a cost effective, broad and reliable examination of DNA methylation profile on MspI/HpaII restriction sites, is fully reproducible and the source code is available on GitHub (https://github.com/wendelljpereira/ms-dart-seq).


Assuntos
Análise Custo-Benefício , Metilação de DNA/genética , Eucalyptus/genética , Técnicas de Genotipagem/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Folhas de Planta/genética , Análise de Sequência de DNA/métodos , Árvores/genética , Cromossomos de Plantas/genética , Enzimas de Restrição do DNA/genética , Elementos de DNA Transponíveis/genética , Genes de Plantas/genética , Técnicas de Genotipagem/economia , Sequenciamento de Nucleotídeos em Larga Escala/economia , Projetos Piloto , Reprodutibilidade dos Testes , Mapeamento por Restrição , Análise de Sequência de DNA/economia , Sulfitos/farmacologia
15.
Ann Bot ; 126(5): 865-872, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32463869

RESUMO

BACKGROUND AND AIMS: Highly controlled experiments document that plant genetic diversity and relatedness can shape herbivore communities and patterns of herbivory. Evidence from the field is, however, scarce and inconsistent. We assessed whether a genetic signal underlying herbivory can be detected in oak woodlands when accounting for variation at smaller (within-tree) and larger (among-stand) scales. METHODS: We tested relationships between tree genetic relatedness, leaf chemical defences and insect herbivory for different canopy layers in 240 trees from 15 pedunculate oak (Quercus robur) forest stands. We partitioned sources of variability in herbivory and defences among stands, individuals and branches. KEY RESULTS: Leaf defences, insect herbivory and their relationship differed systematically between the upper and the lower tree canopy. When accounting for this canopy effect, the variation explained by tree genetic relatedness rose from 2.8 to 34.1 % for herbivory and from 7.1 to 13.8 % for leaf defences. The effect was driven by markedly stronger relationships in the upper canopy. CONCLUSIONS: Our findings illustrate that considerable effects of the host plant genotype on levels of leaf chemical defences and associated insect herbivory can be detected in natural tree populations when within-individual variation is properly accounted for.


Assuntos
Herbivoria , Quercus , Animais , Insetos , Folhas de Planta , Quercus/genética , Árvores/genética
16.
BMC Evol Biol ; 20(1): 44, 2020 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-32306974

RESUMO

BACKGROUND: The Mexican hand tree or Canac (Chiranthodendron pentadactylon) is a temperate tree species of cloud and pine-oak forests of southern Mexico and Guatemala. Its characteristic hand-shaped flower is used in folk medicine and has constituted the iconic symbol of the Sociedad Botánica de México since 1940. Here, the evolutionary history of this species was estimated through phylogeographic analyses of nuclear DNA sequences obtained through restriction site associated DNA sequencing and ecological niche modeling. Total genomic DNA was extracted from leaf samples obtained from a representative number (5 to 10 per sampling site) of individuals distributed along the species geographic range. In Mexico, population is comprised by spatially isolated individuals which may follow the trends of cloud forest fragmentation. By contrast, in Guatemala Chiranthodendron may constitute a canopy dominant species near the Acatenango volcano. The distributional range of this species encompasses geographic provinces separated by the Isthmus of Tehuantepec. The objectives of the study were to: (i) estimate its genetic structure to define whether the observed range disjunction exerted by the Isthmus of Tehuantepec translates into separate populations, (ii) link population divergence timing and demographic trends to historical climate change, and (iii) test hypotheses related to Pleistocene refugia. RESULTS: Patterns of genetic diversity indicated high levels of genetic differentiation between populations separated by the Isthmus. The western and eastern population diverged approximately 0.873 Million years ago (Ma). Demographic analyses supported a simultaneous split from an ancestral population and rapid expansion from a small stock approximately 0.2 Ma corresponding to a glacial period. The populations have remained stable since the LIG (130 Kilo years ago (Ka)). Species distribution modelling (SDM) predicted a decrease in potential distribution in the Last Interglacial (LIG) and an increase during the Last Glacial Maximum (LGM) (22 Ka), Mid-Holocene (6 Ka) and present times. CONCLUSIONS: Divergence time estimations support the hypothesis that populations represent Quaternary relict elements of a species with broader and northernmost distribution. Pleistocene climatic shifts exerted major influence on the distribution of populations allowing dispersion during episodes of suitable climatic conditions and structuring during the first interglacial with a time period length of 100 Kilo years (Kyr) and the vicariant influence of the Isthmus. Limited demographic expansion and population connectivity during the LGM supports the moist forest hypothesis model.


Assuntos
Evolução Biológica , Malvaceae/classificação , Floresta Úmida , Árvores/classificação , Núcleo Celular , Mudança Climática , DNA de Plantas , Ecossistema , Humanos , Malvaceae/genética , México , Filogeografia , Análise de Sequência de DNA , Árvores/genética
17.
PLoS One ; 15(4): e0226863, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32240194

RESUMO

Global trade and climate change are responsible for a surge in foreign invasive species and emerging pests and pathogens across the world. Early detection and surveillance activities are essential to monitor the environment and prevent or mitigate future ecosystem impacts. Molecular diagnostics by DNA testing has become an integral part of this process. However, for environmental applications, there is a need for cost-effective and efficient point-of-use DNA testing to obtain accurate results from remote sites in real-time. This requires the development of simple and fast sample processing and DNA extraction, room-temperature stable reagents and a portable instrument. We developed a point-of-use real-time Polymerase Chain Reaction system using a crude buffer-based DNA extraction protocol and lyophilized, pre-made, reactions for on-site applications. We demonstrate the use of this approach with pathogens and pests covering a broad spectrum of known undesirable forest enemies: the fungi Sphaerulina musiva, Cronartium ribicola and Cronartium comandrae, the oomycete Phytophthora ramorum and the insect Lymantria dispar. We obtained positive DNA identification from a variety of different tissues, including infected leaves, pathogen spores, or insect legs and antenna. The assays were accurate and yielded no false positive nor negative. The shelf-life of the lyophilized reactions was confirmed after one year at room temperature. Finally, successful tests conducted with portable thermocyclers and disposable instruments demonstrate the suitability of the method, named in Situ Processing and Efficient Environmental Detection (iSPEED), for field testing. This kit fits in a backpack and can be carried to remote locations for accurate and rapid detection of pests and pathogens.


Assuntos
Monitoramento Ambiental , Fungos/isolamento & purificação , Espécies Introduzidas , Árvores/microbiologia , Mudança Climática , Ecossistema , Florestas , Fungos/genética , Fungos/patogenicidade , Humanos , Controle de Pragas/métodos , Reação em Cadeia da Polimerase , Árvores/genética , Árvores/crescimento & desenvolvimento
18.
PLoS One ; 15(3): e0229843, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32150571

RESUMO

Seasonal phenomena in plants are primarily affected by day length and temperature. The shoot transcriptomes of trees grown in the field and a controlled-environment chamber were compared to characterize genes that control annual rhythms and the effects of day length- and temperature-regulated genes in the gymnosperm Japanese cedar (Cryptomeria japonica D. Don), which exhibits seasonally indeterminate growth. Annual transcriptome dynamics were clearly demonstrated by principal component analysis using microarray data obtained under field-grown conditions. Analysis of microarray data from trees grown in a controlled chamber identified 2,314 targets exhibiting significantly different expression patterns under short-day (SD) and long-day conditions, and 2,045 targets exhibited significantly different expression patterns at 15°C (LT; low temperature) versus 25°C. Interestingly, although growth was suppressed under both SD and LT conditions, approximately 80% of the SD- and LT-regulated targets differed, suggesting that each factor plays a unique role in the annual cycle. The top 1,000 up-regulated targets in the growth/dormant period in the field coincided with more than 50% of the SD- and LT-regulated targets, and gene co-expression network analysis of the annual transcriptome indicated a close relationship between the SD- and LT-regulated targets. These results indicate that the respective effects of day length and temperature interact to control annual transcriptome dynamics. Well-known upstream genes of signaling pathways responsive to environmental conditions, such as the core clock (LHY/CjLHYb and CCA1/CjLHYa) and PEBP family (MFT) genes, exhibited unique expression patterns in Japanese cedar compared with previous reports in other species, suggesting that these genes control differences in seasonal regulation mechanisms between species. The results of this study provide new insights into seasonal regulation of transcription in Japanese cedar.


Assuntos
Cryptomeria/genética , Regulação da Expressão Gênica de Plantas , Estações do Ano , Temperatura , Transcriptoma , Cycadopsida/genética , Genes de Plantas/genética , Genes Reguladores , Árvores/genética , Árvores/metabolismo
19.
Tree Physiol ; 40(7): 886-903, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32175581

RESUMO

Under increasingly harsh climatic conditions, conservation of threatened species requires integrative studies to understand stress tolerance. Riparian Ulmus minor Mill. populations have been massively reduced by Dutch Elm disease (DED). However, resistant genotypes were selected to restore lost populations. To understand the acclimation mechanisms to the succession of abiotic stresses, ramets of five DED-tolerant U. minor genotypes were subjected to flood and subsequently to drought. Physiological and biochemical responses were evaluated together with shifts in root-fungal assemblages. During both stresses, plants exhibited a decline in leaf net photosynthesis and an increase in percentage loss of stem hydraulic conductivity and in leaf and root proline content. Stomatal closure was produced by chemical signals during flood and hydraulic signals during drought. Despite broad similarities in plant response to both stresses, root-mycobiome shifts were markedly different. The five genotypes were similarly tolerant to moderate drought, however, flood tolerance varied between genotypes. In general, flood did not enhance drought susceptibility due to fast flood recovery, nevertheless, different responses to drought after flood were observed between genotypes. Associations were found between some fungal taxonomic groups and plant functional traits varying with flood and drought (e.g. proline, chlorophyll and starch content) indicating that the thriving of certain taxa depends on host responses to abiotic stress.


Assuntos
Secas , Micobioma/genética , Inundações , Fotossíntese , Folhas de Planta , Estresse Fisiológico , Árvores/genética
20.
Proc Natl Acad Sci U S A ; 117(4): 2201-2210, 2020 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-31932448

RESUMO

Aging is a universal property of multicellular organisms. Although some tree species can live for centuries or millennia, the molecular and metabolic mechanisms underlying their longevity are unclear. To address this, we investigated age-related changes in the vascular cambium from 15- to 667-y-old Ginkgo biloba trees. The ring width decreased sharply during the first 100 to 200 y, with only a slight change after 200 y of age, accompanied by decreasing numbers of cambial cell layers. In contrast, average basal area increment (BAI) continuously increased with aging, showing that the lateral meristem can retain indeterminacy in old trees. The indole-3-acetic acid (IAA) concentration in cambial cells decreased with age, whereas the content of abscisic acid (ABA) increased significantly. In addition, cell division-, cell expansion-, and differentiation-related genes exhibited significantly lower expression in old trees, especially miR166 and HD-ZIP III interaction networks involved in cambial activity. Disease resistance-associated genes retained high expression in old trees, along with genes associated with synthesis of preformed protective secondary metabolites. Comprehensive evaluation of the expression of genes related to autophagy, senescence, and age-related miRNAs, together with analysis of leaf photosynthetic efficiencies and seed germination rates, demonstrated that the old trees are still in a healthy, mature state, and senescence is not manifested at the whole-plant level. Taken together, our results reveal that long-lived trees have evolved compensatory mechanisms to maintain a balance between growth and aging processes. This involves continued cambial divisions, high expression of resistance-associated genes, and continued synthetic capacity of preformed protective secondary metabolites.


Assuntos
Câmbio/metabolismo , Ginkgo biloba/crescimento & desenvolvimento , Árvores/crescimento & desenvolvimento , Ácido Abscísico/metabolismo , Câmbio/citologia , Ginkgo biloba/genética , Ginkgo biloba/metabolismo , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Planta/biossíntese , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Tempo , Árvores/genética , Árvores/metabolismo
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