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1.
Plant Genome ; 13(1): e20012, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-33016625

RESUMO

Genomic selection (GS) based recurrent selection methods were developed to accelerate the domestication of intermediate wheatgrass [IWG, Thinopyrum intermedium (Host) Barkworth & D.R. Dewey]. A subset of the breeding population phenotyped at multiple environments is used to train GS models and then predict trait values of the breeding population. In this study, we implemented several GS models that investigated the use of additive and dominance effects and G×E interaction effects to understand how they affected trait predictions in intermediate wheatgrass. We evaluated 451 genotypes from the University of Minnesota IWG breeding program for nine agronomic and domestication traits at two Minnesota locations during 2017-2018. Genet-mean based heritabilities for these traits ranged from 0.34 to 0.77. Using four-fold cross validation, we observed the highest predictive abilities (correlation of 0.67) in models that considered G×E effects. When G×E effects were fitted in GS models, trait predictions improved by 18%, 15%, 20%, and 23% for yield, spike weight, spike length, and free threshing, respectively. Genomic selection models with dominance effects showed only modest increases of up to 3% and were trait-dependent. Cross-environment predictions were better for high heritability traits such as spike length, shatter resistance, free threshing, grain weight, and seed length than traits with low heritability and large environmental variance such as spike weight, grain yield, and seed width. Our results confirm that GS can accelerate IWG domestication by increasing genetic gain per breeding cycle and assist in selection of genotypes with promise of better performance in diverse environments.


Assuntos
Agropyron , Melhoramento Vegetal , Agropyron/genética , Genoma de Planta , Genômica , Poaceae/genética
2.
Plant Mol Biol ; 104(1-2): 203-215, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32683610

RESUMO

KEY MESSAGE: Distinct catalytic features of the Poaceae TPS-a subfamily arose early in grass evolution and the reactions catalyzed have become more complex with time. The structural diversity of terpenes found in nature is mainly determined by terpene synthases (TPS). TPS enzymes accept ubiquitous prenyl diphosphates as substrates and convert them into the various terpene skeletons by catalyzing a carbocation-driven reaction. Based on their sequence similarity, terpene synthases from land plants can be divided into different subfamilies, TPS-a to TPS-h. In this study, we aimed to understand the evolution and functional diversification of the TPS-a subfamily in the Poaceae (the grass family), a plant family that contains important crops such as maize, wheat, rice, and sorghum. Sequence comparisons showed that aside from one clade shared with other monocot plants, the Poaceae TPS-a subfamily consists of five well-defined clades I-V, the common ancestor of which probably originated very early in the evolution of the grasses. A survey of the TPS literature and the characterization of representative TPS enzymes from clades I-III revealed clade-specific substrate and product specificities. The enzymes in both clade I and II function as sesquiterpene synthases with clade I enzymes catalyzing initial C10-C1 or C11-C1 ring closures and clade II enzymes catalyzing C6-C1 closures. The enzymes of clade III mainly act as monoterpene synthases, forming cyclic and acyclic monoterpenes. The reconstruction and characterization of clade ancestors demonstrated that the differences among clades I-III were already present in their ancestors. However, the ancestors generally catalyzed simpler reactions with less double-bond isomerization and fewer cyclization steps. Overall, our data indicate an early origin of key enzymatic features of TPS-a enzymes in the Poaceae, and the development of more complex reactions over the course of evolution.


Assuntos
Alquil e Aril Transferases/genética , Alquil e Aril Transferases/metabolismo , Poaceae/enzimologia , Poaceae/genética , Alquil e Aril Transferases/classificação , Clonagem Molecular , Escherichia coli/genética , Evolução Molecular , Genes de Plantas/genética , Liases Intramoleculares/metabolismo , Proteínas de Plantas/genética , Análise de Sequência , Terpenos/metabolismo
3.
PLoS One ; 15(7): e0235972, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32687533

RESUMO

Manila grass (Zoysia matrella), a warm-season turfgrass, usually wilts and browns by late autumn because of low temperature. To elucidate the molecular mechanisms regarding Manila grass responses to cold stress, we performed transcriptome sequencing of leaves exposed to 4°C for 0 (CK), 2h (2h_CT) and 72h (72h_CT) by Illumina technology. Approximately 250 million paired-end reads were obtained and de novo assembled into 82,605 unigenes. A total of 34,879 unigenes were annotated by comparing their sequence to public protein databases. At the 2h- and 72h-cold time points, 324 and 5,851 differentially expressed genes (DEGs) were identified, respectively. Gene ontology (GO) and metabolism pathway (KEGG) enrichment analyses of DEGs indicated that auxin, gibberellins, ethylene and calcium took part in the cold signal transduction in the early period. And in the late cold period, electron transport activities, photosynthetic machinery and activity, carbohydrate and nitrogen metabolism, redox equilibrium and hormone metabolism were disturbed. Low temperature stress triggered high light, drought and oxidative stress. At the physiological level, cold stress induced a decrease in water content, an increase in levels of total soluble sugar, free proline and MDA, and changes in bioactive gibberellins levels, which supported the changes in gene expression. The results provided a large set of sequence data of Manila grass as well as molecular mechanisms of the grass in response to cold stress. This information will be helpful for future study of molecular breeding and turf management.


Assuntos
Resposta ao Choque Frio , Regulação da Expressão Gênica de Plantas , Metaboloma , Proteínas de Plantas/genética , Poaceae/genética , Poaceae/fisiologia , Biologia Computacional , Perfilação da Expressão Gênica , Proteínas de Plantas/metabolismo , Poaceae/metabolismo , Transdução de Sinais , Transcriptoma
5.
Ann Bot ; 126(3): 481-497, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32445476

RESUMO

BACKGROUND AND AIMS: Rhizomes are key organs for the establishment of perennial grass stands and adaptation to environmental stress. However, mechanisms regulating rhizome initiation and elongation under drought stress and during post-drought recovery remain unclear. The objective of this study is to investigate molecular factors and metabolic processes involved in drought effects and post-drought recovery in rhizome growth in perennial grass species by comparative transcriptomic and proteomic profiling. METHODS: Tall fescue (Festuca arundinacea) (B-type rhizome genotype, 'BR') plants were exposed to drought stress and re-watering in growth chambers. The number and length of rhizomes were measured following drought stress and re-watering. Hormone and sugar contents were analysed, and transcriptomic and proteomic analyses were performed to identify metabolic factors, genes and proteins associated with rhizome development. KEY RESULTS: Rhizome initiation and elongation were inhibited by drought stress, and were associated with increases in the contents of abscisic acid (ABA) and soluble sugars, but declines in the contents of indoleacetic acid (IAA), zeatin riboside (ZR) and gibberellin (GA4). Genes involved in multiple metabolic processes and stress defence systems related to rhizome initiation exhibited different responses to drought stress, including ABA signalling, energy metabolism and stress protection. Drought-inhibition of rhizome elongation could be mainly associated with the alteration of GA4 and antioxidants contents, energy metabolism and stress response proteins. Upon re-watering, new rhizomes were regenerated from rhizome nodes previously exposed to drought stress, which was accompanied by the decline in ABA content and increases in IAA, ZR and GA4, as well as genes and proteins for auxin, lipids, lignin and nitrogen metabolism. CONCLUSIONS: Drought-inhibition of rhizome initiation and elongation in tall fescue was mainly associated with adjustments in hormone metabolism, carbohydrate metabolism and stress-defence systems. Rhizome regeneration in response to re-watering involved reactivation of hormone and lipid metabolism, secondary cell-wall development, and nitrogen remobilization and cycling.


Assuntos
Secas , Poaceae/genética , Ácido Abscísico , Regulação da Expressão Gênica de Plantas , Proteômica , Rizoma
6.
Science ; 368(6493)2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32273397

RESUMO

Fusarium head blight (FHB), a fungal disease caused by Fusarium species that produce food toxins, currently devastates wheat production worldwide, yet few resistance resources have been discovered in wheat germplasm. Here, we cloned the FHB resistance gene Fhb7 by assembling the genome of Thinopyrum elongatum, a species used in wheat distant hybridization breeding. Fhb7 encodes a glutathione S-transferase (GST) and confers broad resistance to Fusarium species by detoxifying trichothecenes through de-epoxidation. Fhb7 GST homologs are absent in plants, and our evidence supports that Th. elongatum has gained Fhb7 through horizontal gene transfer (HGT) from an endophytic Epichloë species. Fhb7 introgressions in wheat confers resistance to both FHB and crown rot in diverse wheat backgrounds without yield penalty, providing a solution for Fusarium resistance breeding.


Assuntos
Resistência à Doença/genética , Epichloe/genética , Fusarium/patogenicidade , Transferência Genética Horizontal , Glutationa Transferase/genética , Doenças das Plantas/microbiologia , Triticum/genética , Triticum/microbiologia , Clonagem Molecular , Melhoramento Vegetal , Poaceae/genética
7.
Artigo em Inglês | MEDLINE | ID: mdl-32224382

RESUMO

Osmotic stresses caused by reduced water availability or the accumulation of salts in the soil can be highly damaging to plants. The objective of this study was to investigate physiological responses and tolerance mechanisms of two turfgrass species (seashore paspalum and centipedegrass) with distinct differences in salinity tolerance exposed to osmotic and iso-osmotic salt stresses. Three turfgrass genotypes including seashore paspalums 'Seastar' and 'UGP113', and centipedegrass 'TifBlair' were grown in ½ strength Hoagland's solution with three different treatment conditions; control (no external addition), salt stress (-0.4 MPa by adding NaCl) and osmotic stress [-0.4 MPa by adding polyethylene glycol (PEG)]. Osmotic stress damages were more severe with greater reductions in turf quality, photochemical efficiency (Fv/Fm), relative water content (RWC) and leaf water potential (Ψw) compared to iso-osmotic salt stress in both seashore paspalum and centipedegrass. Greater osmotic adjustment (OA) with greater accumulation of metabolically inexpensive inorganic osmolytes (Na+) helped turfgrasses to lessen damages in salt stress compared to osmotic stress. However, such accumulation of Na+ resulted ion-toxicity and triggered some damages in terms of increased electrolyte leakage (EL) and reduced total protein in salt-sensitive centipedegrass. Seashore paspalum had better ion regulation and also maintained greater antioxidant enzyme activities compared to centipedegrass; therefore it was able to avoid ion-specific damages under salt stress. Differences in the utilization of specific solutes for osmotic adjustment and antioxidant metabolism are partially responsible for the differences in salt versus osmotic stress responses in these species; the regulation of these defense mechanisms requires further investigation.


Assuntos
Pressão Osmótica , Poaceae/fisiologia , Estresse Salino , Tolerância ao Sal , Genótipo , Paspalum/crescimento & desenvolvimento , Paspalum/fisiologia , Poaceae/genética
8.
Tree Physiol ; 40(9): 1217-1231, 2020 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-32333784

RESUMO

Acid invertases (INVs) play a pivotal role in both vegetative and reproductive growth of plants. However, their possible functions in fast-growing plants such as bamboo are largely unknown. Here, we report the molecular characterization of acid INVs in Phyllostachys heterocycla cv. pubescens, a fast-growing bamboo species commercially grown worldwide. Nine acid INVs (PhINVs), including seven cell wall INVs (PhCWINV1, PhCWINV2, PhCWINV3, PhCWINV4, PhCWINV5, PhCWINV6 and PhCWINV7) and two vacuolar INVs (PhVINV11 and PhVINV12) were isolated. Bioinformatic analyses demonstrated that they all share high amino acid identity with other INVs from different plant species and contain the motifs typically conserved in acid INV. Enzyme activity assays revealed a significantly higher INV activity in the fast-growing tissues, such as the elongating internodes of stems. Detailed quantitative reverse-transcription PCR analyses showed various expression patterns of PhINVs at different developmental stages of the elongating stems. With the exception of PhCWINV6, all PhINVs were ubiquitously expressed in a developmental-specific manner. Further studies in Arabidopsis exhibited that constitutive expression of PhCWINV1, PhCWINV4 or PhCWINV7 increased the biomass production of transgenic plants, as indicated by augmented plant heights and shoot dry weights than the wild-type plants. All these results suggest that acid INVs play a crucial role in the internode elongation of P. heterocycla cv. pubescens and would provide valuable information for the dissection of their exact biological functions in the fast growth of bamboo.


Assuntos
Arabidopsis , beta-Frutofuranosidase/genética , Parede Celular , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas/genética , Poaceae/genética
9.
Proc Natl Acad Sci U S A ; 117(18): 10079-10088, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32327609

RESUMO

Grasses are among the most resilient plants, and some can survive prolonged desiccation in semiarid regions with seasonal rainfall. However, the genetic elements that distinguish grasses that are sensitive versus tolerant to extreme drying are largely unknown. Here, we leveraged comparative genomic approaches with the desiccation-tolerant grass Eragrostis nindensis and the related desiccation-sensitive cereal Eragrostis tef to identify changes underlying desiccation tolerance. These analyses were extended across C4 grasses and cereals to identify broader evolutionary conservation and divergence. Across diverse genomic datasets, we identified changes in chromatin architecture, methylation, gene duplications, and expression dynamics related to desiccation in E. nindensis It was previously hypothesized that transcriptional rewiring of seed desiccation pathways confers vegetative desiccation tolerance. Here, we demonstrate that the majority of seed-dehydration-related genes showed similar expression patterns in leaves of both desiccation-tolerant and -sensitive species. However, we identified a small set of seed-related orthologs with expression specific to desiccation-tolerant species. This supports a broad role for seed-related genes, where many are involved in typical drought responses, with only a small subset of crucial genes specifically induced in desiccation-tolerant plants.


Assuntos
Adaptação Fisiológica/genética , Eragrostis/genética , Genômica , Poaceae/genética , Cromatina/genética , Metilação de DNA/genética , Dessecação , Secas , Eragrostis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Genoma de Planta/genética , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Poaceae/crescimento & desenvolvimento , Estresse Fisiológico/genética , Água/metabolismo
10.
Nat Commun ; 11(1): 1123, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111840

RESUMO

Stem rust is an important disease of wheat that can be controlled using resistance genes. The gene SuSr-D1 identified in cultivar 'Canthatch' suppresses stem rust resistance. SuSr-D1 mutants are resistant to several races of stem rust that are virulent on wild-type plants. Here we identify SuSr-D1 by sequencing flow-sorted chromosomes, mutagenesis, and map-based cloning. The gene encodes Med15, a subunit of the Mediator Complex, a conserved protein complex in eukaryotes that regulates expression of protein-coding genes. Nonsense mutations in Med15b.D result in expression of stem rust resistance. Time-course RNAseq analysis show a significant reduction or complete loss of differential gene expression at 24 h post inoculation in med15b.D mutants, suggesting that transcriptional reprogramming at this time point is not required for immunity to stem rust. Suppression is a common phenomenon and this study provides novel insight into suppression of rust resistance in wheat.


Assuntos
Resistência à Doença/genética , Complexo Mediador/genética , Doenças das Plantas/genética , Triticum/genética , Basidiomycota/patogenicidade , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Duplicação Gênica , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Mutação , Fenótipo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Poaceae/classificação , Poaceae/genética , Triticum/imunologia , Triticum/microbiologia
11.
Food Chem ; 318: 126483, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32126468

RESUMO

In this study, the antioxidant activity of germinating Chinese wild rice was found to decline initially, after which it increased. The largest difference in antioxidant activity was observed between the 36-h (G36) and the 120-h germination (G120) stage. We further assessed the dynamic changes in metabolites, phenolic acids, flavonoids, and phenolic biosynthetic genes in germinating Chinese wild rice. Ultra-high performance liquid chromatography-triple quadrupole mass spectrometry revealed that 315 metabolites were up-regulated and 28 were down-regulated between G36 and G120. Levels of p-hydroxybenzoic acid, p-hydroxybenzaldehyde, vanillin, p-coumaric acid, ferulic acid, and epigallocatechin increased significantly during germination. Gene expression of four phenylalanine ammonia-lyases, one 4-coumarate-CoA ligase, one cinnamoyl-CoA reductase, two cinnamyl alcohol dehydrogenases, one chalcone synthase, and one chalcone isomerase was significantly higher at G120 than at G36 and promoted phenolics accumulation. This study elucidated the biochemical mechanisms involved in antioxidant activity and phenolic profile changes during Chinese wild rice germination.


Assuntos
Antioxidantes/metabolismo , Flavonoides/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Fenóis/metabolismo , Proteínas de Plantas/genética , Poaceae/fisiologia , Aciltransferases/genética , Cromatografia Líquida de Alta Pressão , Coenzima A Ligases/genética , Germinação , Hidroxibenzoatos/metabolismo , Liases Intramoleculares/genética , Espectrometria de Massas , Oxirredutases/genética , Fenilalanina Amônia-Liase/genética , Poaceae/química , Poaceae/genética , Sementes/química , Sementes/genética , Sementes/fisiologia
12.
Yi Chuan ; 42(2): 194-211, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32102776

RESUMO

As a coastal halophyte, Spartina alterniflora has high salt tolerance. However, the mechanism at the molecular level has not been widely studied due to the absence of a reference genome. The proteins of NAC families are plant-specific transcription factors that regulate the growth, development and stress response in plants. To identify the NAC family and explore the relationship between NAC proteins and the growth, development and stress response of Spatina alterniflora, full-length transcriptome data of Spartina alterniflora by the third generation sequencing technology was used as reference sequences in this study to blast with the NAC protein sequences from Oryza sativa, Arabidopsis thaliana and Zea mays. Finally, 62 SaNAC proteins were found in Spartina alterniflora by deep analysis on conserved domains. Then we analyzed sequence alignment, evolution, motif prediction, homology comparison, subcellular localization, tissue and abiotic stress-induced gene differential expression profile on the NAC family members in Spartina alterniflora. As a result, all SaNAC proteins were found containing a conserved NAM domain and having certain evolutionary similarity with rice; two family proteins, SaNAC9 and SaNAC49, were expressed in the nucleus; moreover, SaNAC genes were identified to have distinct expressional profiles in different tissues and stress response of Spartina alterniflora. These results indicated the SaNAC transcription factor family not only had conserved functional domains but also played important role in the regulation of growth, development and abiotic stress response.


Assuntos
Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Poaceae/genética , Plantas Tolerantes a Sal/genética , Fatores de Transcrição/genética , Filogenia , Estresse Fisiológico
13.
Plant Mol Biol ; 103(1-2): 63-74, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32040757

RESUMO

KEY MESSAGE: PSBR1 is a moso bamboo gene negatively regulated by brassinosteroid, which encodes a mitochondrial localized protein. Overexpression of PSBR1 leads to growth inhibition in various growth progresses in Arabidopsis. The young shoot of moso bamboo (Phyllostachys edulis) is known as one of the fastest growing plant organs. The roles of phytohormones in the fast-growth of bamboo shoot are not fully understood. Brassinosteroids (BRs) are a group of growth-promoting steroid hormones that play important roles in cell elongation and division. While BR related genes are highly enriched in fast-growing internodes in moso bamboo, the functions of BR in the fast-growth process is not understood at the molecular level. Here, we identified a poaceae specific gene, PSBR1 (Poaceae specific and BR responsive gene 1) from the moso bamboo genome. PSBR1 was highly expressed in the stem and leaves of bamboo seedling, and the elongating nodes of fast-growing bamboo shoot. PSBR1's expression is increased by BR biosynthesis inhibitor propiconazole but decreased by BR treatment. PSBR1 encodes a novel protein that is localized to the mitochondria in tobacco and bamboo protoplast. The Arabidopsis transgenic plants overexpressing PSBR1 show growth inhibition in both vegetative and reproductive stages. This study suggests that PSBR1 is a BR regulated mitochondrial protein in bamboo, which inhibits plant growth when overexpressed in Arabidopsis.


Assuntos
Brassinosteroides/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas Mitocondriais/genética , Proteínas de Plantas/genética , Poaceae/genética , Arabidopsis/genética , Reguladores de Crescimento de Planta/genética , Reguladores de Crescimento de Planta/metabolismo , Plantas Geneticamente Modificadas
14.
Mol Phylogenet Evol ; 146: 106758, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32028031

RESUMO

The Bambusa-Dendrocalamus-Gigantochloa complex (BDG complex) is the most diversified and phylogenetically recalcitrant group of the paleotropical woody bamboos. Species of this complex occur in tropical and subtropical Asia and most of them are of great economic, cultural and ecological value. The lack of resolution achieved through the analyses of previous molecular datasets has long confounded its phylogenetic estimation and generic delimitation. Here, we adopted a ddRAD-seq strategy to investigate phylogenetic relationships of the four main genera (Bambusa, Dendrocalamus, Gigantochloa, and Melocalamus) in the BDG complex. A total of 102 species were sampled, and SNP data were generated. Both MP and ML analyses of the ddRAD-seq data resulted in a well-resolved topology with Gigantochloa and Melocalamus confirmed as monophyletic, and Melocalamus resolved as sister to the rest of the complex. Bambusa and Dendrocalamus were both resolved as paraphyletic. The phylogenetic relationships were mostly supported by morphological evidence including characters of the branch complement, rachilla, lodicules, filaments and stigma. We also generated and assembled complete plastid genomes of 48 representative species. There were conflicts between the plastome and the ddRAD topologies. Our study demonstrated that RAD-seq can be used to reconstruct evolutionary history of lineages such as the bamboos where ancient hybridization and polyploidy play a significant role. The four genera of the BDG complex have a complex evolutionary history which is likely a product of ancient introgression events.


Assuntos
Bambusa/classificação , Poaceae/classificação , Ásia , Bambusa/genética , Evolução Biológica , Genomas de Plastídeos , Hibridização Genética , Filogenia , Poaceae/anatomia & histologia , Poaceae/genética , Polimorfismo de Nucleotídeo Único , Poliploidia , Análise de Sequência de DNA
15.
Artigo em Inglês | MEDLINE | ID: mdl-32088578

RESUMO

Multiple-herbicide resistant (MHR) weeds are a global problem and a looming threat to weed control in crops. MHR weeds express a specific phi class glutathione transferase (MHR-GSTF) which seems to contribute to herbicide resistance. The present work aims to investigate the structure and catalytic properties of the MHR-GSTFs from different grass weeds and crops (Alopecurus myosuroides, Lolium rigidum, Hordeum vulgare, Triticum aestivum). Recombinant MHR-GSTFs were expressed in E. coli and purified by affinity chromatography. Kinetic analysis of substrate specificity using a range of thiol substrates and xenobiotic compounds suggested that all enzymes display a broad range of specificity and are capable of detoxifying major stress-induced toxic products. Notably, all tested enzymes exhibited high activity towards organic hydroperoxides. The crystal structure of MHR-GSTF from Alopecurus myosuroides (AmGSTF) was determined by molecular replacement at 1.33 Å resolution. The enzyme was resolved with bound glutathione sulfenic acid (GSOH) at the G-site and succinic acid at the H-site. The enzyme shows conserved structural features compared to other Phi class GSTs. However, some differences were observed at the C-terminal helix H9 that may affect substrate specificity. The structural and functional features of AmGSTF were compared with those of the homologue crop enzymes (HvGSTF and TaGSTF) and discussed in light of their contribution to the MHR mechanism.


Assuntos
Resistência a Medicamentos , Glutationa Transferase , Resistência a Herbicidas , Poaceae , Resistência a Medicamentos/genética , Escherichia coli , Glutationa Transferase/química , Glutationa Transferase/metabolismo , Resistência a Herbicidas/genética , Cinética , Poaceae/enzimologia , Poaceae/genética
16.
Plant Mol Biol ; 102(4-5): 447-462, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31898148

RESUMO

KEY MESSAGE: ZjICE2 works as a positive regulator in abiotic stress responses and ZjICE2 is a valuable genetic resource to improve abiotic stress tolerance in the molecular breeding program of Zoysia japonica. The basic helix-loop-helix (bHLH) family transcription factors (TFs) play an important role in response to biotic or abiotic stresses in plants. However, the functions of bHLH TFs in Zoysia japonica, one of the warm-season turfgrasses, remain poorly understood. Here, we identified ZjICE2 from Z. japonica, a novel MYC-type bHLH transcription factor that was closely related to ICE homologs in the phylogenetic tree, and its expression was regulated by various abiotic stresses. Transient expression of ZjICE2-GFP in onion epidermal cells revealed that ZjICE2 was a nuclear-localized protein. Also, ZjICE2 bound the MYC cis-element in the promoter of dehydration responsive element binding 1 of Z. japonica (ZjDREB1) using yeast one-hybrid assay. A phenotypic analysis showed that overexpression of the ZjICE2 in Arabidopsis enhanced tolerance to cold, drought, and salt stresses. The transgenic Arabidopsis and Z. japonica accumulated more transcripts of cold-responsive DREB/CBFs and their downstream genes than the wild type (WT) after cold treatment. Furthermore, the transgenic plants exhibited an enhanced Reactive oxygen species (ROS) scavenging ability, which resulted in an efficient maintenance of oxidant-antioxidant homeostasis. In addition, overexpression of the ZjICE2 in Z. japonica displayed intensive cold tolerance with increases in chlorophyll contents and photosynthetic efficiency. Our study suggests that ZjICE2 works as a positive regulator in abiotic stress responses and the ICE-DREB/CBFs response pathway involved in cold stress tolerance is also conserved in Z. japonica. These results provide a valuable genetic resource for the molecular breeding program especially for warm-season grasses as well as other leaf crop plants.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/fisiologia , Poaceae/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Temperatura Baixa , Resposta ao Choque Frio , Secas , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/fisiologia , Poaceae/genética , Regulon , Tolerância ao Sal , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Ativação Transcricional
17.
BMC Res Notes ; 13(1): 35, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31952556

RESUMO

OBJECTIVE: Grasslands are widespread ecosystems that fulfil many functions. Plant species richness (PSR) is known to have beneficial effects on such functions and monitoring PSR is crucial for tracking the effects of land use and agricultural management on these ecosystems. Unfortunately, traditional morphology-based methods are labor-intensive and cannot be adapted for high-throughput assessments. DNA barcoding could aid increasing the throughput of PSR assessments in grasslands. In this proof-of-concept work, we aimed at determining which of three plant DNA barcodes (rbcLa, matK and trnH-psbA) best discriminates 16 key grass and legume species common in temperate sub-alpine grasslands. RESULTS: Barcode trnH-psbA had a 100% correct assignment rate (CAR) in the five analyzed legumes, followed by rbcLa (93.3%) and matK (55.6%). Barcode trnH-psbA had a 100% CAR in the grasses Cynosurus cristatus, Dactylis glomerata and Trisetum flavescens. However, the closely related Festuca, Lolium and Poa species were not always correctly identified, which led to an overall CAR in grasses of 66.7%, 50.0% and 46.4% for trnH-psbA, matK and rbcLa, respectively. Barcode trnH-psbA is thus the most promising candidate for PSR assessments in permanent grasslands and could greatly support plant biodiversity monitoring on a larger scale.


Assuntos
Código de Barras de DNA Taxonômico/métodos , DNA Intergênico/genética , Fabaceae/genética , Poaceae/genética , Biodiversidade , DNA de Plantas , Ecossistema , Filogenia , Análise de Sequência de DNA , Especificidade da Espécie
18.
DNA Cell Biol ; 39(2): 273-288, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31968175

RESUMO

Cleistogenes songorica is a cultivated turfgrass species that employs a mixed breeding system. To determine the morphological differences and molecular mechanisms of the chasmogamous (CH) and cleistogamous (CL) flowers of this species, we evaluated seed traits and analyzed six transcription factor (TF) families related to floral development. The seed traits from the CH and CL flowers were significantly different. In total, 12 CsAP2, 13 CsSPL, 9 CsGRF, 21 CsMYB, 15 CsMADS, and 1 CsLFY differentially expressed genes were identified from the transcriptome of the C. songorica flowers, which was further supported by evolutionary relationships and conserved motifs. All collinear gene pairs had a Ka/Ks ratio <1. Analysis of the promoters and miRNAs of the TFs revealed that the members of the six TF families may coregulate the divergence of CH and CL flowers during evolution. Two CsAP2, 8 CsSPL, 6 CsGRF, 3 CsMYB (targeted by miR172s, miR156s, miR396a/b and miR159a/b, respectively), and 15 CsMADS genes as well as 1 CsLFY gene may be involved in the development of CH and CL flowers. This study is the first to analyze the differences between CH and CL flowers at the TF-family level, which will help in the understanding of dimorphic turfgrasses.


Assuntos
Flores/genética , Poaceae/genética , Fatores de Transcrição/genética , Regulação da Expressão Gênica de Plantas/genética , MicroRNAs/genética , Fenótipo , Plantas/genética , RNA Mensageiro/genética , Sementes/genética , Fatores de Transcrição/metabolismo , Transcriptoma/genética
19.
Plant Mol Biol ; 102(1-2): 55-72, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31748889

RESUMO

KEY MESSAGE: Differential expression of mi-RNAs targeting developmental processes and progressive downregulation of repeat-associated siRNAs following genome merger and genome duplication in the context of allopolyploid speciation in Spartina. The role of small RNAs on gene expression regulation and genome stability is arousing increased interest and is being explored in various plant systems. In spite of prominence of reticulate evolution and polyploidy that affects the evolutionary history of all plant lineages, very few studies analysed RNAi mechanisms with this respect. Here, we explored small RNAs diversity and expression in the context of recent allopolyploid speciation, using the Spartina system, which offers a unique opportunity to explore the immediate changes following hybridization and genome duplication. Small RNA-Seq analyses were conducted on hexaploid parental species (S. alterniflora and S. maritima), their F1 hybrid S. x townsendii, and the neoallododecaploid S. anglica. We identified 594 miRNAs, 2197 miRNA-target genes, and 3730 repeat-associated siRNAs (mostly targeting Class I/Copia-Ivana- Copia-SIRE and LINEs elements). For both mi- and ra-siRNAs, we detected differential expression patterns following genome merger and genome duplication. These misregulations include non-additive expression of miRNAs in the F1 hybrid and additional changes in the allopolyploid targeting developmental processes. Expression of repeat-associated siRNAs indicates a strengthen of transposable element repression during the allopolyploidization process. Altogether, these results confirm the central role small RNAs play in shaping regulatory changes in naturally formed recent allopolyploids.


Assuntos
Regulação da Expressão Gênica de Plantas , Hibridização Genética , MicroRNAs/genética , MicroRNAs/metabolismo , Poaceae/genética , Poaceae/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Sequência de Bases , Elementos de DNA Transponíveis , DNA de Plantas , Genes de Plantas/genética , Genoma de Planta , Instabilidade Genômica , Anotação de Sequência Molecular , Poliploidia
20.
Physiol Plant ; 168(1): 118-132, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31090074

RESUMO

Mineral nutrient supply can affect the hydraulic property of roots. The aim of the present work on sheepgrass (Leymus chinensis L.) plants was to test whether any changes in root hydraulic conductivity (Lp; exudation analyses) in response to a growth-limiting supply of phosphate (P) are accompanied by changes in (1) cell Lp via measuring the cell pressure, (2) the aquaporin (AQP) gene expression by performing qPCR and (3) the formation of apoplastic barriers, by analyzing suberin lamella and Casparian bands via cross-sectional analyses in roots. Plants were grown hydroponically on complete nutrient solution, containing 250 µM P, until they were 31-36 days old, and then kept for 2-3 weeks on either complete solution, or transferred on solution containing 2.5 µM (low-P) or no added P (no-P). Phosphate treatments caused significant decreases in root and cell-Lp and AQP gene expression, while the formation of apoplastic barriers increased, particularly in lateral roots. Experiments using the AQP inhibitor mercury (Hg) suggested that a significant portion of radial root water uptake in sheepgrass occurs along a path involving AQPs, and that the Lp of this path is reduced under low- and no-P. It is concluded that a growth-limiting supply of phosphate causes parallel changes in (1) cell Lp and aquaporin gene expression (decrease) and (2) apoplastic barrier formation (increase), and that the two may combine to reduce root Lp. The reduction in root Lp, in turn, facilitates an increased root-to-shoot surface area ratio, which allocates resources to the root, sourcing the limiting nutrient.


Assuntos
Aquaporinas/genética , Fosfatos , Proteínas de Plantas/genética , Raízes de Plantas/fisiologia , Poaceae/fisiologia , Transporte Biológico , Estudos Transversais , Regulação da Expressão Gênica de Plantas , Exsudatos de Plantas , Poaceae/genética , Água
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