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1.
BMC Plant Biol ; 24(1): 629, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38961339

RESUMO

Twisted trunks are not uncommon in trees, but their effects on tree growth are still unclear. Among coniferous tree species, the phenomenon of trunk distortion is more prominent in Pinus yunnanensis. To expand the germplasm of genetic resources, we selected families with excellent phenotypic traits to provide material for advanced generation breeding. The progeny test containing 93 superior families (3240 trees) was used as the research material. Phenotypic measurements and estimated genetic parameters (family heritability, realistic gain and genetic gain) were performed at 9, 15, and 18 years of age, respectively. The genetic evaluation yielded the following results (1) The intra-family variance component of plant height (PH) was greater than that of the inter-family, while the inter-family variance components of other traits (diameter at breast height (DBH), crown diameter (CD), height under branches (HUB), degree of stem-straightness (DS)) were greater than that of the intra-family, indicating that there was abundant variation among families and potential for selection. (2) At half rotation period (18 years old), there was a significant correlation among the traits. The proportion of trees with twisted trunks (level 1-3 straightness) reached 48%. The DS significantly affected growth traits, among which PH and DBH were the most affected. The volume loss rate caused by twisted trunk was 18.06-56.75%, implying that trunk distortion could not be completely eliminated after an artificial selection. (3) The influence of tree shape, crown width, and trunk on volume increased, and the early-late correlation between PH, DBH and volume was extremely significant. The range of phenotypic coefficient of variation, genetic variation coefficient and family heritability of growth traits (PH, DBH, and volume) were 44.29-127.13%, 22.88-60.87%, and 0.79-0.83, respectively. (4) A total of 21 superior families were selected by the method of membership function combined with independent selection. Compared with the mid-term selection (18 years old), the accuracy of early selection (9 years old) reached 77.5%. The selected families' genetic gain and realistic gain range were 5.79-19.82% and 7.12-24.27%, respectively. This study can provide some useful reference for the breeding of coniferous species.


Assuntos
Fenótipo , Pinus , Pinus/genética , Pinus/crescimento & desenvolvimento , Pinus/fisiologia , Árvores/crescimento & desenvolvimento , Árvores/genética , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/genética , Caules de Planta/anatomia & histologia , Melhoramento Vegetal
2.
Int J Mol Sci ; 25(13)2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-39000509

RESUMO

Dwarfing rootstocks enhance planting density, lower tree height, and reduce both labor in peach production. Cerasus humilis is distinguished by its dwarf stature, rapid growth, and robust fruiting capabilities, presenting substantial potential for further development. In this study, Ruipan 4 was used as the scion and grafted onto Amygdalus persica and Cerasus humilis, respectively. The results indicate that compared to grafting combination R/M (Ruipan 4/Amygdalus persica), grafting combination R/O (Ruipan 4/Cerasus humilis) plants show a significant reduction in height and a significant increase in flower buds. RNA-seq indicates that genes related to gibberellin (GA) and auxin metabolism are involved in the dwarfing process of scions mediated by C. humilis. The expression levels of the GA metabolism-related gene PpGA2ox7 significantly increased in R/O and are strongly correlated with plant height, branch length, and internode length. Furthermore, GA levels were significantly reduced in R/O. The transcription factor PpGATA21 was identified through yeast one-hybrid screening of the PpGA2ox7 promoter. Yeast one-hybrid (Y1H) and dual-luciferase reporter (DLR) demonstrate that PpGATA21 can bind to the promoter of PpGA2ox7 and activate its expression. Overall, PpGATA21 activates the expression of the GA-related gene PpGA2ox7, resulting in reduced GA levels and consequent dwarfing of plants mediated by C. humilis. This study provides new insights into the mechanisms of C. humilis and offers a scientific foundation for the dwarfing and high-density cultivation of peach trees.


Assuntos
Regulação da Expressão Gênica de Plantas , Giberelinas , Proteínas de Plantas , Prunus persica , Prunus persica/genética , Prunus persica/crescimento & desenvolvimento , Prunus persica/metabolismo , Giberelinas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Regiões Promotoras Genéticas , Árvores/genética , Árvores/crescimento & desenvolvimento , Ácidos Indolacéticos/metabolismo
3.
Sci Data ; 11(1): 775, 2024 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-39003271

RESUMO

Kmeria septentrionalis is a critically endangered tree endemic to Guangxi, China, and is listed on the International Union for Conservation of Nature's Red List. The lack of genetic information and high-quality genome data has hindered conservation efforts and studies on this species. In this study, we present a chromosome-level genome assembly of K. septentrionalis. The genome was initially assembled to be 2.57 Gb, with a contig N50 of 11.93 Mb. Hi-C guided genome assembly allowed us to anchor 98.83% of the total length of the initial contigs onto 19 pseudochromosomes, resulting in a scaffold N50 of 135.08 Mb. The final chromosome-level genome, spaning 2.54 Gb, achieved a BUSCO completeness of 98.9% and contained 1.67 Gb repetitive elements and 35,927 coding genes. This high-quality genome assembly provides a valuable resource for understanding the genetic basis of conservation-related traits and biological properties of this endangered tree species. Furthermore, it lays a critical foundation for evolutionary studies within the Magnoliaceae family.


Assuntos
Espécies em Perigo de Extinção , Genoma de Planta , Cromossomos de Plantas , China , Árvores/genética
4.
Glob Chang Biol ; 30(6): e17347, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38822663

RESUMO

Climate change (CC) necessitates reforestation/afforestation programs to mitigate its impacts and maximize carbon sequestration. But comprehending how tree growth, a proxy for fitness and resilience, responds to CC is critical to maximize these programs' effectiveness. Variability in tree response to CC across populations can notably be influenced by the standing genetic variation encompassing both neutral and adaptive genetic diversity. Here, a framework is proposed to assess tree growth potential at the population scale while accounting for standing genetic variation. We applied this framework to black spruce (BS, Picea mariana [Mill] B.S.P.), with the objectives to (1) determine the key climate variables having impacted BS growth response from 1974 to 2019, (2) examine the relative roles of local adaptation and the phylogeographic structure in this response, and (3) project BS growth under two Shared Socioeconomic Pathways while taking standing genetic variation into account. We modeled growth using a machine learning algorithm trained with dendroecological and genetic data obtained from over 2600 trees (62 populations divided in three genetic clusters) in four 48-year-old common gardens, and simulated growth until year 2100 at the common garden locations. Our study revealed that high summer and autumn temperatures negatively impacted BS growth. As a consequence of warming, this species is projected to experience a decline in growth by the end of the century, suggesting maladaptation to anticipated CC and a potential threat to its carbon sequestration capacity. This being said, we observed a clear difference in response to CC within and among genetic clusters, with the western cluster being more impacted than the central and eastern clusters. Our results show that intraspecific genetic variation, notably associated with the phylogeographic structure, must be considered when estimating the response of widespread species to CC.


Assuntos
Sequestro de Carbono , Mudança Climática , Variação Genética , Picea , Árvores , Picea/genética , Picea/crescimento & desenvolvimento , Árvores/genética , Árvores/crescimento & desenvolvimento , Filogeografia
5.
Genes (Basel) ; 15(6)2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38927602

RESUMO

The low survival rate of transplanted plantlets, which has limited the utility of tissue-culture-based methods for the rapid propagation of tree peonies, is due to plantlet dormancy after rooting. We previously determined that the auxin response factor PsARF may be a key regulator of tree peony dormancy. To clarify the mechanism mediating tree peony plantlet dormancy, PsARF genes were systematically identified and analyzed. Additionally, PsARF16a was transiently expressed in the leaves of tree peony plantlets to examine its regulatory effects on a downstream gene network. Nineteen PsARF genes were identified and divided into four classes. All PsARF genes encoded proteins with conserved B3 and ARF domains. The number of motifs, exons, and introns varied between PsARF genes in different classes. The overexpression of PsARF16a altered the expression of NCED, ZEP, PYL, GA2ox1, GID1, and other key genes in abscisic acid (ABA) and gibberellin (GA) signal transduction pathways, thereby promoting ABA synthesis and decreasing GA synthesis. Significant changes to the expression of some key genes contributing to starch and sugar metabolism (e.g., AMY2A, BAM3, BGLU, STP, and SUS2) may be associated with the gradual conversion of sugar into starch. This study provides important insights into PsARF functions in tree peonies.


Assuntos
Regulação da Expressão Gênica de Plantas , Paeonia , Dormência de Plantas , Proteínas de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Dormência de Plantas/genética , Paeonia/genética , Paeonia/crescimento & desenvolvimento , Paeonia/metabolismo , Ácido Abscísico/metabolismo , Giberelinas/metabolismo , Reguladores de Crescimento de Plantas/genética , Reguladores de Crescimento de Plantas/metabolismo , Árvores/genética , Árvores/crescimento & desenvolvimento , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transdução de Sinais/genética
6.
New Phytol ; 243(2): 705-719, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38803110

RESUMO

Understanding the genetic basis of how plants defend against pathogens is important to monitor and maintain resilient tree populations. Swiss needle cast (SNC) and Rhabdocline needle cast (RNC) epidemics are responsible for major damage of forest ecosystems in North America. Here we investigate the genetic architecture of tolerance and resistance to needle cast diseases in Douglas-fir (Pseudotsuga menziesii) caused by two fungal pathogens: SNC caused by Nothophaeocryptopus gaeumannii, and RNC caused by Rhabdocline pseudotsugae. We performed case-control genome-wide association analyses and found disease resistance and tolerance in Douglas-fir to be polygenic and under strong selection. We show that stomatal regulation as well as ethylene and jasmonic acid pathways are important for resisting SNC infection, and secondary metabolite pathways play a role in tolerating SNC once the plant is infected. We identify a major transcriptional regulator of plant defense, ERF1, as the top candidate for RNC resistance. Our findings shed light on the highly polygenic architectures underlying fungal disease resistance and tolerance and have important implications for forestry and conservation as the climate changes.


Assuntos
Ascomicetos , Resistência à Doença , Estudo de Associação Genômica Ampla , Doenças das Plantas , Pseudotsuga , Resistência à Doença/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Pseudotsuga/genética , Pseudotsuga/microbiologia , Pseudotsuga/fisiologia , Ascomicetos/fisiologia , Ascomicetos/patogenicidade , Árvores/genética , Adaptação Fisiológica/genética , Herança Multifatorial , Regulação da Expressão Gênica de Plantas , Genes de Plantas
7.
Sci Adv ; 10(22): eado6611, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38820152

RESUMO

Northern glacial refugia are a hotly debated concept. The idea that many temperate organisms survived the Last Glacial Maximum (LGM; ~26.5 to 19 thousand years) in several sites across central and northern Europe stems from phylogeographic analyses, yet direct fossil evidence has thus far been missing. Here, we present the first unequivocal proof that thermophilous trees such as oak (Quercus), linden (Tilia), and common ash (Fraxinus excelsior) survived the LGM in Central Europe. The persistence of the refugium was promoted by a steady influx of hydrothermal waters that locally maintained a humid and warm microclimate. We reconstructed the geological and palaeohydrological factors responsible for the emergence of hot springs during the LGM and argue that refugia of this type, allowing the long-term survival and rapid post-LGM dispersal of temperate elements, were not exceptional in the European periglacial zone.


Assuntos
Fontes Termais , Refúgio de Vida Selvagem , Árvores , Europa (Continente) , Árvores/genética , Filogeografia , Clima Desértico , Camada de Gelo , Fósseis , Quercus/genética
8.
Heredity (Edinb) ; 132(6): 309-319, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38714843

RESUMO

Callicarpa subpubescens, endemic to the Ogasawara Islands, is suggested to have multiple ecotypes in the Hahajima Islands, specifically in the central part of the Ogasawara Islands. In this study, associations between genetic groups and spatial distribution, habitat, leaf morphology, size structure, and flowering time of each genetic group were investigated on Hahajima and the satellite Imoutojima Islands. Genetic groups were identified using EST-SSR markers, revealing four ecotypes named based on morphological features: Dwarf (D), Glabrescent (G), Tall (T), and Middle (M), with M being a result of the hybridization of G and T. Ecotype D, adapted to dry environments, is characterized by small tree size, dense thick leaves with abundant hairs, and is distributed in dry scrub. Ecotype G, adapted to understory of mesic forests, lacks leaf hairs. Ecotype T, adapted to the canopy of mesic forests, has hairy leaves and is tall in tree height. Ecotype M, adapted to the canopy of mesic scrub or edges of mesic forests, has hairy leaves but with a shorter tree height than ecotype T. Flowering peaks differed among all ecotype pairs except G and M, but the flowering times more or less overlapped among all ecotypes, suggesting that pre-mating isolation among ecotypes is not perfect. Post-mating isolation is considered absent, as there were no differences in the results, germination, and survival rates of one-year seedlings among inter- and intra-ecotype crossings. The existence of such ecotypes provides valuable insights into the ongoing speciation processes adapting to the oceanic island environments.


Assuntos
Ecótipo , Variação Genética , Ilhas , Fenótipo , Folhas de Planta , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/anatomia & histologia , Ecossistema , Árvores/genética , Árvores/crescimento & desenvolvimento , Repetições de Microssatélites/genética , Genética Populacional , Flores/genética , Flores/anatomia & histologia
9.
Am J Bot ; 111(4): e16312, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38576091

RESUMO

Forests are facing unprecedented levels of stress from pest and disease outbreaks, disturbance, fragmentation, development, and a changing climate. These selective agents act to alter forest composition from regional to cellular levels. Thus, a central challenge for understanding how forests will be impacted by future change is how to integrate across scales of biology. Phenotype, or an observable trait, is the product of an individual's genes (G) and the environment in which an organism lives (E). To date, researchers have detailed how environment drives variation in tree phenotypes over long time periods (e.g., long-term ecological research sites [LTERs]) and across large spatial scales (e.g., flux network). In parallel, researchers have discovered the genes and pathways that govern phenotypes, finding high degrees of genetic control and signatures of local adaptation in many plant traits. However, the research in these two areas remain largely independent of each other, hindering our ability to generate accurate predictions of plant response to environment, an increasingly urgent need given threats to forest systems. I present the importance of both genes and environment in determining tree responses to climate stress. I highlight why the difference between G versus E in driving variation is critical for our understanding of climate responses, then propose means of accelerating research that examines G and E simultaneously by leveraging existing long-term, large-scale phenotypic data sets from ecological networks and adding newly affordable sequence (-omics) data to both drill down to find the genes and alleles influencing phenotypes and scale up to find how patterns of demography and local adaptation may influence future response to change.


Assuntos
Mudança Climática , Fenótipo , Árvores , Árvores/genética , Árvores/fisiologia , Florestas , Variação Genética
10.
Methods Mol Biol ; 2787: 95-103, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38656484

RESUMO

Our method describes how to collect forest tree root tips in the field, to store them for transfer to the lab, to pretreat root tips in order to arrest cells in metaphase, fix root tips to preserve specific morphological organizations, to stain fixed root tips by Feulgen's Reaction in order to increase contrast, and to prepare the root meristem for analyzing mitotic stages and chromosomal aberrations via light microscopy. We further describe how to classify chromosomal abnormalities and quantify them via aberration indices.


Assuntos
Meristema , Árvores , Meristema/genética , Árvores/genética , Aberrações Cromossômicas , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Análise Citogenética/métodos
11.
PLoS One ; 19(3): e0293817, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38512884

RESUMO

Phytophthora pluvialis is an oomycete that primarily infects Pinus radiata and Pseudotsuga menziesii causing the destructive foliar disease red needle cast (RNC). Recent observations show that P. pluvialis can also infect western hemlock inducing resinous cankers. High-throughput and reproducible infection assays are integral to find key information on tree health and oomycete pathogenicity. In this protocol, we describe the propagation and spore induction of P. pluvialis, followed by detached needle assays for verification and quantification of virulence of P. pluvialis in P. radiata needles. These needle assays can be employed for high-throughput screening of tree needles with diverse genetic backgrounds. In downstream analysis, Quantitative PCR (qPCR) was utilized to assess relative gene expression, as exemplified by candidate RxLR effector protein PpR01. Additional techniques like RNA sequencing, metabolomics, and proteomics can be combined with needle assays and can offer comprehensive insights into P. pluvialis infection mechanisms.


Assuntos
Phytophthora , Pinus , Phytophthora/genética , Proteínas/metabolismo , Pinus/genética , Sequência de Bases , Árvores/genética , Esporos , Doenças das Plantas
12.
Mol Plant ; 17(5): 725-746, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38486452

RESUMO

Understanding the underlying mechanisms and links between genome evolution and adaptive innovations stands as a key goal in evolutionary studies. Poplars, among the world's most widely distributed and cultivated trees, exhibit extensive phenotypic diversity and environmental adaptability. In this study, we present a genus-level super-pangenome comprising 19 Populus genomes, revealing the likely pivotal role of private genes in facilitating local environmental and climate adaptation. Through the integration of pangenomes with transcriptomes, methylomes, and chromatin accessibility mapping, we unveil that the evolutionary trajectories of pangenes and duplicated genes are closely linked to local genomic landscapes of regulatory and epigenetic architectures, notably CG methylation in gene-body regions. Further comparative genomic analyses have enabled the identification of 142 202 structural variants across species that intersect with a significant number of genes and contribute substantially to both phenotypic and adaptive divergence. We have experimentally validated a ∼180-bp presence/absence variant affecting the expression of the CUC2 gene, crucial for leaf serration formation. Finally, we developed a user-friendly web-based tool encompassing the multi-omics resources associated with the Populus super-pangenome (http://www.populus-superpangenome.com). Together, the present pioneering super-pangenome resource in forest trees not only aids in the advancement of breeding efforts of this globally important tree genus but also offers valuable insights into potential avenues for comprehending tree biology.


Assuntos
Genoma de Planta , Populus , Populus/genética , Árvores/genética , Adaptação Fisiológica/genética , Florestas , Genômica , Transcriptoma/genética
13.
Plant Cell Environ ; 47(6): 2058-2073, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38404129

RESUMO

Plants adjust their growth and development in response to changing light caused by canopy shade. The molecular mechanisms underlying shade avoidance responses have been widely studied in Arabidopsis and annual crop species, yet the shade avoidance signalling in woody perennial trees remains poorly understood. Here, we first showed that PtophyB1/2 photoreceptors serve conserved roles in attenuating the shade avoidance syndrome (SAS) in poplars. Next, we conducted a systematic identification and characterization of eight PtoPIF genes in Populus tomentosa. Knocking out different PtoPIFs led to attenuated shade responses to varying extents, whereas overexpression of PtoPIFs, particularly PtoPIF3.1 and PtoPIF3.2, led to constitutive SAS phenotypes under normal light and enhanced SAS responses under simulated shade. Notably, our results revealed that distinct from Arabidopsis PIF4 and PIF5, which are major regulators of SAS, the Populus homologues PtoPIF4.1 and PtoPIF4.2 seem to play a minor role in controlling shade responses. Moreover, we showed that PtoPIF3.1/3.2 could directly activate the expression of the auxin biosynthetic gene PtoYUC8 in response to shade, suggesting a conserved PIF-YUC-auxin pathway in modulating SAS in tree. Overall, our study provides insights into shared and divergent functions of PtoPIF members in regulating various aspects of the SAS in Populus.


Assuntos
Regulação da Expressão Gênica de Plantas , Fitocromo , Proteínas de Plantas , Populus , Populus/genética , Populus/efeitos da radiação , Populus/metabolismo , Populus/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fitocromo/metabolismo , Fitocromo/genética , Luz , Ácidos Indolacéticos/metabolismo , Plantas Geneticamente Modificadas , Árvores/fisiologia , Árvores/genética , Árvores/metabolismo
14.
Plant Physiol ; 195(2): 1229-1255, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38366651

RESUMO

Trees with weeping shoot architectures are valued for their beauty and are a resource for understanding how plants regulate posture control. The peach (Prunus persica) weeping phenotype, which has elliptical downward arching branches, is caused by a homozygous mutation in the WEEP gene. Little is known about the function of WEEP despite its high conservation throughout Plantae. Here, we present the results of anatomical, biochemical, biomechanical, physiological, and molecular experiments that provide insight into WEEP function. Our data suggest that weeping peach trees do not have defects in branch structure. Rather, transcriptomes from the adaxial (upper) and abaxial (lower) sides of standard and weeping branch shoot tips revealed flipped expression patterns for genes associated with early auxin response, tissue patterning, cell elongation, and tension wood development. This suggests that WEEP promotes polar auxin transport toward the lower side during shoot gravitropic response, leading to cell elongation and tension wood development. In addition, weeping peach trees exhibited steeper root systems and faster lateral root gravitropic response. This suggests that WEEP moderates root gravitropism and is essential to establishing the set-point angle of lateral roots from the gravity vector. Additionally, size exclusion chromatography indicated that WEEP proteins self-oligomerize, like other proteins with sterile alpha motif domains. Collectively, our results from weeping peach provide insight into polar auxin transport mechanisms associated with gravitropism and lateral shoot and root orientation.


Assuntos
Gravitropismo , Ácidos Indolacéticos , Proteínas de Plantas , Prunus persica , Ácidos Indolacéticos/metabolismo , Gravitropismo/fisiologia , Gravitropismo/genética , Prunus persica/genética , Prunus persica/fisiologia , Prunus persica/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Brotos de Planta/genética , Brotos de Planta/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Gravitação , Árvores/fisiologia , Árvores/genética
15.
J Hered ; 115(2): 221-229, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38305464

RESUMO

Island oak (Quercus tomentella) is a rare relictual island tree species that exists only on six islands off the coast of California and Mexico, but was once widespread throughout mainland California. Currently, this species is endangered by threats such as non-native plants, grazing animals, and human removal. Efforts for conservation and restoration of island oak currently underway could benefit from information about its range-wide genetic structure and evolutionary history. Here we present a high-quality genome assembly for Q. tomentella, assembled using PacBio HiFi and Omni-C sequencing, developed as part of the California Conservation Genomics Project (CCGP). The resulting assembly has a length of 781 Mb, with a contig N50 of 22.0 Mb and a scaffold N50 of 63.4 Mb. This genome assembly will provide a resource for genomics-informed conservation of this rare oak species. Additionally, this reference genome will be the first one available for a species in Quercus section Protobalanus, a unique oak clade present only in western North America.


Assuntos
Quercus , Árvores , Animais , Humanos , Árvores/genética , Genômica , México , América do Norte
16.
Proc Natl Acad Sci U S A ; 121(10): e2313312121, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38412128

RESUMO

Somatic mutations potentially play a role in plant evolution, but common expectations pertaining to plant somatic mutations remain insufficiently tested. Unlike in most animals, the plant germline is assumed to be set aside late in development, leading to the expectation that plants accumulate somatic mutations along growth. Therefore, several predictions were made on the fate of somatic mutations: mutations have generally low frequency in plant tissues; mutations at high frequency have a higher chance of intergenerational transmission; branching topology of the tree dictates mutation distribution; and exposure to UV (ultraviolet) radiation increases mutagenesis. To provide insights into mutation accumulation and transmission in plants, we produced two high-quality reference genomes and a unique dataset of 60 high-coverage whole-genome sequences of two tropical tree species, Dicorynia guianensis (Fabaceae) and Sextonia rubra (Lauraceae). We identified 15,066 de novo somatic mutations in D. guianensis and 3,208 in S. rubra, surprisingly almost all found at low frequency. We demonstrate that 1) low-frequency mutations can be transmitted to the next generation; 2) mutation phylogenies deviate from the branching topology of the tree; and 3) mutation rates and mutation spectra are not demonstrably affected by differences in UV exposure. Altogether, our results suggest far more complex links between plant growth, aging, UV exposure, and mutation rates than commonly thought.


Assuntos
Fabaceae , Lauraceae , Animais , Árvores/genética , Mutação , Taxa de Mutação
17.
BMC Genomics ; 25(1): 180, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38355402

RESUMO

Pecan scab is a devastating disease that causes damage to pecan (Carya illinoinensis (Wangenh.) K. Koch) fruit and leaves. The disease is caused by the fungus Venturia effusa (G. Winter) and the main management practice for controlling the disease is by application of fungicides at 2-to-3-week intervals throughout the growing season. Besides disease-related yield loss, application of fungicides can result in considerable cost and increases the likelihood of fungicide resistance developing in the pathogen. Resistant cultivars are available for pecan growers; although, in several cases resistance has been overcome as the pathogen adapts to infect resistant hosts. Despite the importance of host resistance in scab management, there is little information regarding the molecular basis of genetic resistance to pecan scab.The purpose of this study was to elucidate mechanisms of natural pecan scab resistance by analyzing transcripts that are differentially expressed in pecan leaf samples from scab resistant and susceptible trees. The leaf samples were collected from trees in a provenance collection orchard that represents the natural range of pecan in the US and Mexico. Trees in the orchard have been exposed to natural scab infections since planting in 1989, and scab ratings were collected over three seasons. Based on this data, ten susceptible trees and ten resistant trees were selected for analysis. RNA-seq data was collected and analyzed for diseased and non-diseased parts of susceptible trees as well as for resistant trees. A total of 313 genes were found to be differentially expressed when comparing resistant and susceptible trees without disease. For susceptible samples showing scab symptoms, 1,454 genes were identified as differentially expressed compared to non-diseased susceptible samples. Many genes involved in pathogen recognition, defense responses, and signal transduction were up-regulated in diseased samples of susceptible trees, whereas differentially expressed genes in pecan scab resistant samples were generally down-regulated compared to non-diseased susceptible samples.Our results provide the first account of candidate genes involved in resistance/susceptibility to pecan scab under natural conditions in a pecan orchard. This information can be used to aid pecan breeding programs and development of biotechnology-based approaches for generating pecan cultivars with more durable scab resistance.


Assuntos
Ascomicetos , Carya , Fungicidas Industriais , Carya/genética , Carya/microbiologia , Transcriptoma , Árvores/genética , Ascomicetos/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Melhoramento Vegetal
18.
Physiol Plant ; 176(1): e14218, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38383691

RESUMO

Withstanding extreme cold stress is a prerequisite for alpine treeline trees to persist and survive. However, the underlying mechanism by which treeline trees sense phenological changes and survive hard winters has not been fully elucidated. Here, we investigated the physiology, transcriptome, and metabolome of the subalpine treeline species Larix chinensis to identify the molecular mechanism of phenological and cold resistance. Calcium and antioxidant enzyme activities (e.g., superoxide dismutase and glutathione peroxidase) are essential for coping with winter cold stress in L. chinensis. Transcriptome analysis revealed that circadian rhythm and phytohormone signalling transduction played important roles in regulating L. chinensis phenological changes and cold stress responses. The variations in the transcriptome identified were accompanied by the specific accumulation of flavones, flavonols, and monosaccharides. The flavonoid biosynthesis and phenylpropanoid biosynthesis pathways played important roles in the adaptation of L. chinensis to the extreme winter environment, and flavone and flavonol biosynthesis was an important pathway involved in bud burst. In addition, temperature and photoperiod had synergistic influences on the formation and release of bud dormancy. Thus, our findings provided new insights into the mechanism of subalpine treeline formation.


Assuntos
Multiômica , Árvores , Árvores/genética , Temperatura , Temperatura Baixa , Estações do Ano
19.
BMC Genomics ; 25(1): 9, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38166623

RESUMO

BACKGROUND: Planting tested forest reproductive material is crucial to ensure the increased resilience of intensively managed productive stands for timber and wood product markets under climate change scenarios. Single-step Genomic Best Linear Unbiased Prediction (ssGBLUP) analysis is a cost-effective option for using genomic tools to enhance the accuracy of predicted breeding values and genetic parameter estimation in forest tree species. Here, we tested the efficiency of ssGBLUP in a tropical multipurpose tree species, Cordia africana, by partial population genotyping. A total of 8070 trees from three breeding seedling orchards (BSOs) were phenotyped for height. We genotyped 6.1% of the phenotyped individuals with 4373 single nucleotide polymorphisms. The results of ssGBLUP were compared with pedigree-based best linear unbiased prediction (ABLUP) and genomic best linear unbiased prediction (GBLUP), based on genetic parameters, theoretical accuracy of breeding values, selection candidate ranking, genetic gain, and predictive accuracy and prediction bias. RESULTS: Genotyping a subset of the study population provided insights into the level of relatedness in BSOs, allowing better genetic management. Due to the inbreeding detected within the genotyped provenances, we estimated genetic parameters both with and without accounting for inbreeding. The ssGBLUP model showed improved performance in terms of additive genetic variance and theoretical breeding value accuracy. Similarly, ssGBLUP showed improved predictive accuracy and lower bias than the pedigree-based relationship matrix (ABLUP). CONCLUSIONS: This study of C. africana, a species in decline due to deforestation and selective logging, revealed inbreeding depression. The provenance exhibiting the highest level of inbreeding had the poorest overall performance. The use of different relationship matrices and accounting for inbreeding did not substantially affect the ranking of candidate individuals. This is the first study of this approach in a tropical multipurpose tree species, and the analysed BSOs represent the primary effort to breed C. africana.


Assuntos
Cordia , Árvores , Humanos , Árvores/genética , Melhoramento Vegetal , Genoma , Genômica/métodos , Genótipo , Fenótipo , Modelos Genéticos
20.
BMC Genom Data ; 25(1): 2, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38166632

RESUMO

OBJECTIVES: Lasiodiplodia pseudotheobromae is an important fungal pathogen associated with die-back, canker and shoot blight in many plant hosts with a wide geographic distribution. The aim of our study was to provide high-quality genome assemblies and sequence annotation resources of L. pseudotheobromae, to facilitate future studies on the systematics, population genetics and genomics of the fungal pathogen L. pseudotheobromae. DATA DESCRIPTION: High-quality genomes of five L. pseudotheobromae isolates were sequenced based on Oxford Nanopore technology (ONT) and Illumina HiSeq sequencing platform. The total size of each assembly ranged from 43 Mb to 43.86 Mb and over 11,000 protein-coding genes were predicted from each genome. The proteins of predicted genes were annotated using multiple public databases, among the annotated protein-coding genes, more than 4,300 genes were predicted as potential virulence genes by the Pathogen Host Interactions (PHI) database. Moreover, the genome comparative analysis among L. pseudotheobromae and other closely related species revealed that 7,408 gene clusters were shared among them and 152 gene clusters unique to L. pseudotheobromae. This genome and associated datasets provided here will serve as a useful resource for further analyses of this fungal pathogen species.


Assuntos
Ascomicetos , Eucalyptus , Árvores/genética , Eucalyptus/genética , Genoma , Ascomicetos/genética
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