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1.
Plant Mol Biol ; 102(4-5): 537-551, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31916084

RESUMO

KEY MESSAGE: Silencing of SlCAND1 expression resulted in dwarfish, loss of apical dominance, early flowering, suppression of seed germination, and abnormal root architecture in tomato Cullin-RING E3 ligases (CRLs)-dependent ubiquitin proteasome system mediates degradation of numerous proteins that controls a wide range of developmental and physiological processes in eukaryotes. Cullin-associated Nedd8-dissociated protein 1 (CAND1) acts as an exchange factor allowing substrate recognition part exchange and plays a vital role in reactivating CRLs. The present study reports on the identification of SlCAND1, the only one CAND gene in tomato. SlCAND1 expression is ubiquitous and positively regulated by multiple plant hormones. Silencing of SlCAND1 expression using RNAi strategy resulted in a pleiotropic and gibberellin/auxin-associated phenotypes, including dwarf plant with reduced internode length, loss of apical dominance, early flowering, low seed germination percentage, delayed seed germination speed, short primary root, and increased lateral root proliferation and elongation. Moreover, application of exogenous GA3 or IAA could partly rescue some SlCAND1-silenced phenotypes, and the expression levels of gibberellin/auxin-related genes were altered in SlCAND1-RNAi lines. These facts revealed that SlCAND1 is required for gibberellin/auxin-associated regulatory network in tomato. Although SlCAND1 is crucial for multiple developmental processes during vegetative growth stage, SlCAND1-RNAi lines didn't exhibit visible effect on fruit development and ripening. Meanwhile, we discussed that multiple physiological functions of SlCAND1 in tomato are different to previous report of its ortholog in Arabidopsis. Our study adds a new perspective on the functional roles of CAND1 in plants, and strongly supports the hypothesis that CAND1 and its regulated ubiquitin proteasome system are pivotal for plant vegetative growth but possibly have different roles in diverse plant species.


Assuntos
Flores/fisiologia , Germinação , Lycopersicon esculentum/fisiologia , Proteínas de Plantas/fisiologia , Raízes de Plantas/fisiologia , Arabidopsis/genética , Proteínas Culina , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Giberelinas/metabolismo , Lycopersicon esculentum/genética , Fenótipo , Reguladores de Crescimento de Planta/fisiologia , Proteínas de Plantas/genética , Interferência de RNA , Sementes/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia
2.
Ecotoxicol Environ Saf ; 187: 109785, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31644988

RESUMO

The germination and seedling vigor of crops is negatively affected by soil salinity. Nitric oxide (NO) has emerged as a key molecule involved in many physiological events in plants. The objective of present study was to evaluate the impact of exogenous sodium nitroprusside (SNP, a NO donor) at different concentrations on the seed germination and early seedling growth characteristics of pakchoi (Brassica chinensis L.) under NaCl stress. 100 mM NaCl stress markedly inhibited the seed germination potential, germination index, vitality index and growth of radicles and plumules. SNP pretreatment attenuated the salt stress effects in a dose-dependent manner, as indicated by enhancing the characteristics of seed germination and early seedling growth parameters, and the mitigating effect was most pronounced at 10 µM SNP. Efficient antioxidant systems were activated by SNP pre-treatment, and which effectively increased the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and reduced contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2) and the production rate of superoxide anion radical (O2·-) in radicles and plumules, thereby preventing oxidative damage from NaCl stress. SNP pre-treatment also increased the contents of proline and soluble sugar in radicles and plumules under NaCl stress. In addition, SNP pre-treatment significantly increased the K+ contents and decreased Na+ contents in radicles and plumules, resulting in the increased level of K+/Na+ ratio. Our results demonstrated that SNP application on pakchoi seeds may be a good option to improve seed germination and seedling growth under NaCl stress by modulating the physiological responses resulting in better seed germination and seedling growth.


Assuntos
Brassica/efeitos dos fármacos , Germinação/efeitos dos fármacos , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico/farmacologia , Estresse Salino/efeitos dos fármacos , Antioxidantes/metabolismo , Brassica/crescimento & desenvolvimento , Brassica/metabolismo , Relação Dose-Resposta a Droga , Salinidade , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Sementes/efeitos dos fármacos , Sementes/fisiologia
3.
Plant Biol (Stuttg) ; 22(1): 106-112, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31433536

RESUMO

Several Cerrado tree species have traits and structures that protect from fires. The effectiveness of a trait depends on the fire regime, especially the frequency. We used Vochysia elliptica, a common Cerrado tree, as a model to test whether different fire frequencies alter crown architecture and flower, fruit and seed production. We analysed the effect of fire on the production of inflorescences, fruits and seeds, as well as seed germination and tree architecture of 20 trees in each of three plots of a long-term ecological experiment managed with different fire regimes: burned every 2 years (B), burned every 4 years (Q) in mid-dry season and an area protected from fire (C). We found a large negative effect of fire frequency on crown architecture and on flower and fruit production. Trees in C and Q had significantly more main branches and a larger crown area than trees in B. At its peak, a tree in C was expected to produce 2.4 times more inflorescences than Q, and 15.5 times more than B, with similar magnitudes for fruits. Sixty per cent of trees in B and 10% in Q produced no fruits. The differences in architecture might explain the reduction in sexual reproduction due to a smaller physical space to produce flowers at the branch apices. Resource limitation due to plant investment to replace burned vegetative parts may also decrease sexual reproduction. Our results indicate potentially severe consequences of high fire frequencies for population dynamics and species persistence in Cerrado communities.


Assuntos
Fogo , Pradaria , Árvores , Dinâmica Populacional , Sementes/fisiologia , Árvores/anatomia & histologia , Árvores/fisiologia
4.
Plant Mol Biol ; 102(4-5): 359-372, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31848919

RESUMO

KEY MESSAGE: Protein degradation is essential in plant growth and development. The stability of Cullin3 substrate adaptor protein BPM1 is regulated by multiple environmental cues pointing on manifold control of targeted protein degradation. A small family of six MATH-BTB genes (BPM1-6) is described in Arabidopsis thaliana. BPM proteins are part of the Cullin E3 ubiquitin ligase complexes and are known to bind at least three families of transcription factors: ERF/AP2 class I, homeobox-leucine zipper and R2R3 MYB. By targeting these transcription factors for ubiquitination and subsequent proteasomal degradation, BPMs play an important role in plant flowering, seed development and abiotic stress response. In this study, we generated BPM1-overexpressing plants that showed an early flowering phenotype, resistance to abscisic acid and tolerance to osmotic stress. We analyzed BPM1-GFP protein stability and found that the protein has a high turnover rate and is degraded by the proteasome 26S in a Cullin-dependent manner. Finally, we found that BPM1 protein stability is environmentally conditioned. Darkness and salt stress triggered BPM1 degradation, whereas elevated temperature enhanced BPM1 stability and accumulation in planta.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/fisiologia , Flores/fisiologia , Estresse Fisiológico , Fatores de Transcrição/fisiologia , Ácido Abscísico , Arabidopsis/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde , Raízes de Plantas/fisiologia , Plantas Geneticamente Modificadas , Plasmídeos/genética , Pólen/fisiologia , Complexo de Endopeptidases do Proteassoma/fisiologia , Proteólise , Sementes/fisiologia , Ubiquitina-Proteína Ligases/fisiologia
5.
J Food Sci ; 85(1): 14-20, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31869858

RESUMO

Salinity has drastic effects on plant growth and productivity and is one of the major factors responsible for crop yield losses throughout the agricultural soils of the world. The mechanisms of salinity tolerance in plants are regulated by a set of inherent multigenes and prevalent environmental factors, which bring about a myriad of metabolic changes in each plant part. The stress-induced metabolic changes in the rice plant have been intensively studied, but extensively in plant parts such as stem, leaf, and root. However, little information exists in the literature about such stress-induced architectural and physiological changes in rice grain, a premier staple food of a large proportion of human population. Thus, the current review comprehensively describes the effects of salinity stress on rice grain composition including changes in carbohydrate, protein, fat, and mineral contents. Elucidation of salinity induced changes in rice grain composition would help to understand whether or not a nutritious and healthy staple food is available to human population from rice grown under saline environments.


Assuntos
Oryza/fisiologia , Sementes/química , Oryza/química , Oryza/crescimento & desenvolvimento , Folhas de Planta/química , Folhas de Planta/metabolismo , Estresse Salino , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Estresse Fisiológico
6.
Plant Mol Biol ; 102(4-5): 373-388, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31872309

RESUMO

KEY MESSAGE: CRISPR-edited variants at the 3'-end of OsLOGL5's coding sequence (CDS), significantly increased rice grain yield under well-watered, drought, normal nitrogen, and low nitrogen field conditions at multiple geographical locations. Cytokinins impact numerous aspects of plant growth and development. This study reports that constitutive ectopic overexpression of a rice cytokinin-activation enzyme-like gene, OsLOGL5, significantly reduced primary root growth, tiller number, and yield. Conversely, mutations at the 3'-end of OsLOGL5 CDS resulted in normal rice plant morphology but with increased grain yield under well-watered, drought, normal nitrogen, and low nitrogen field conditions at multiple geographical locations. Six gene edited variants (Edit A to F) were created and tested in the field. Edit-B and Edit-F plants increased, but Edit-D and Edit-E plants decreased, the panicle number per plant. All OsLOGL5-edited plants significantly increased seed setting rate, total grain numbers, full-filled grain numbers per panicle, and thousand seed weight under drought conditions, suggesting that OsLOGL5 is likely involved in the regulation of both seed development and grain filling processes. Our results indicate that the C-terminal end of OsLOGL5 protein plays an important role in regulating rice yield improvement under different abiotic stress conditions, and OsLOGL5 is important for rice yield enhancement and stability.


Assuntos
Citocininas/metabolismo , Grão Comestível/genética , Oryza/genética , Proteínas de Plantas/metabolismo , Sistemas CRISPR-Cas , Secas , Grão Comestível/enzimologia , Edição de Genes , Regulação da Expressão Gênica de Plantas , Nitrogênio , Oryza/enzimologia , Proteínas de Plantas/genética , Raízes de Plantas/fisiologia , Domínios Proteicos , Sementes/fisiologia , Estresse Fisiológico
7.
BMC Plant Biol ; 19(1): 482, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31703691

RESUMO

BACKGROUND: Starch is the main storage substance in rice caryopsis and its properties will determine the quality of rice. Super rice has been extensively studied due to its high-yield characteristics, but the knowledge of amyloplast development and starch quality in caryopsis of super rice especially with large panicle is limited. RESULTS: To address this, large panicle typed and normal panicle typed super rice cultivar Yongyou2640 (YY2640) and Nangeng9108 (NG9108) were investigated in this study. The development of amyloplast in YY2640 caryopsis was better than NG9108, showing faster degradation rate of pericarp amyloplast and better filling degree of endosperm amyloplast. Meanwhile, the starch granule of YY2640 presented as polyhedral shape with smooth surface and the granule size was slightly larger than NG9108. The starch of YY2640 exhibited the lower amylose content, ratio of amylose to amylopectin and the higher level of amylopectin short and long branch-chains compared with NG9108, but there was no significant difference in amylopectin branching degree between them. Two rice starches both showed the characteristics of A-type crystal, and the relative crystallinity and external ordered degree of YY2640 starch were higher than those of NG9108. Furthermore, YY2640 starch showed better pasting properties with lower pasting temperature, shorter pasting time, higher peak viscosity, trough viscosity, breakdown value and lower setback value because of lower apparent amylose content. CONCLUSIONS: Overall, the development and filling of amyloplast in YY2640 caryopsis were better than those of NG9108, thus leading to better starch quality of YY2640.


Assuntos
Oryza/química , Sementes/química , Amido/química , Inflorescência/classificação , Oryza/fisiologia , Sementes/fisiologia , Amido/metabolismo
8.
BMC Plant Biol ; 19(1): 510, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752696

RESUMO

BACKGROUND: Soybean is one of the most important crop sources of tocopherols (Toc). However, the content of α-Toc, an isoform with the highest vitamin E activity in humans, is low in most cultivars. With the aim of broadening genetic variability, we performed quantitative trait locus (QTL) analysis for a high seed α-Toc trait detected in a wild soybean and characterized the sequence polymorphisms and expression profiles of γ-tocopherol methyltransferase (γ-TMT) genes as potential candidates. RESULTS: A recombinant inbred line population was developed from a cross between the low α-Toc breeding line TK780 and the high α-Toc wild accession B04009. The α-Toc content in seeds correlated strongly with the ratio of α-Toc to γ-Toc contents. QTL analysis using a high-density map constructed with 7710 single nucleotide polymorphisms (SNPs) generated by restriction site-associated DNA sequencing detected six QTLs involved in α-Toc biosynthesis. Of these, three in chromosomes (Chr) 9, 11, and 12 produced consistent effects during a 2-year trial. B04009 allele at QTLs in Chr9 and Chr12 and TK780 allele at the QTL in Chr11 each promoted the conversion of γ-Toc to α-Toc, which elevated the seed α-Toc content. SNPs and indels were detected between the parents in three γ-TMT genes (γ-TMT1, γ-TMT2, and γ-TMT3) co-located in the QTLs in Chr9 and Chr12, of which some existed in the cis-regulatory elements associated with seed development and functions. In immature cotyledons, γ-TMT3 was expressed at higher levels in B04009 than TK780, irrespective of two thermal conditions tested, whereas the expression of γ-TMT2 was markedly upregulated under higher temperatures, particularly in B04009. CONCLUSIONS: We identified QTLs consistently controlling α-Toc biosynthesis in wild soybean seeds in 2-year trials. The QTL on Chr9 had been previously identified in soybean, whereas the QTLs on Chr11 and Chr12 were novel. Further molecular dissections and characterization of the QTLs may facilitate the use of high α-Toc alleles from wild soybean in soybean breeding and an understanding of the molecular mechanisms underlying α-Toc biosynthesis in soybean seeds.


Assuntos
Metiltransferases/metabolismo , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genética , Soja/genética , alfa-Tocoferol/metabolismo , Alelos , Cruzamento , Alimento Funcional , Endogamia , Metiltransferases/genética , Fenótipo , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes/genética , Sementes/fisiologia , Análise de Sequência de DNA , Soja/fisiologia , Tocoferóis
9.
J Plant Physiol ; 243: 153054, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31648109

RESUMO

Adhesion of the barley husk to the underlying caryopsis requires the development of a cuticular cementing layer on the caryopsis surface. Differences in adhesion quality among genotypes have previously been correlated with cementing layer composition, which is thought to influence caryopsis cuticle permeability, the hypothesised mechanism of adhesion mediation. It is not yet known whether differences in adhesion quality among genotypes are determined by changes in caryopsis cuticle permeability. We examined changes in candidate cementing layer biosynthetic and regulatory genes to investigate the genetic mechanisms behind husk adhesion quality. We used both commercially relevant UK malting cultivars and older European lines to ensure phenotypic diversity in adhesion quality. An ethylene responsive transcription factor (NUD) is required for the development of the cementing layer. To examine correlations between gene expression, cementing layer permeability and husk adhesion quality we also treated cultivars with ethephon (2-chloroethylphosphonic acid) which breaks down to ethylene, and silver thiosulphate which inhibits ethylene reception, and measured caryopsis cuticle permeability. Differential adhesion qualities among genotypes are not determined by NUD expression during development of the cementing material alone, but could result from differences in biosynthetic gene expression during cementing layer development in response to longer-term NUD expression patterns. Altered caryopsis cuticle permeability does result in altered adhesion quality, but the correlation is not consistently positive or negative. Cuticle permeability is therefore not the mechanism that determines husk adhesion quality, but is likely a consequence of the required cuticular compositional changes that determine adhesion.


Assuntos
Etilenos/metabolismo , Hordeum/fisiologia , Compostos Organofosforados/farmacologia , Reguladores de Crescimento de Planta/farmacologia , Sementes/fisiologia , Tiossulfatos/farmacologia , Adesividade , Etilenos/antagonistas & inibidores , Expressão Gênica/fisiologia , Hordeum/genética , Permeabilidade , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
An Acad Bras Cienc ; 91(4): e20180734, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31644643

RESUMO

Seed companies are looking for promising, quick and effective alternatives to determine the physiological quality of seeds. The objective of the current work was to study the efficiency of the exudate - phenolphthalein pH test to evaluate the seeds of two lots of Libidibia ferrea (Mart. ex Tul.) L. P. Queiroz var. ferrea. The statistical design for the the exudate - phenolphthalein pH test was completely randomized with four replicates of 50 seeds in a factorial design (2 x 5), two seed lots and five soaking periods (30, 60, 90, 120, and 150 minutes), respectively, using two constant temperatures (25 and 30°C). The percentage of viability and germination of the seeds did not differ in the temperatures of 25 and 30°C and in the soaking periods by the exudate - phenolphthalein pH test. Thus, it is recommended that the test be conducted for at least 30 minutes in distilled and deionized water at the constant temperature of 25 or 30°C to evaluate the vigor of the Libidibia ferrea.


Assuntos
Caesalpinia/crescimento & desenvolvimento , Germinação/fisiologia , Fenolftaleína/análise , Sementes/crescimento & desenvolvimento , Caesalpinia/fisiologia , Concentração de Íons de Hidrogênio , Controle de Qualidade , Sementes/fisiologia , Temperatura Ambiente
11.
Theor Appl Genet ; 132(11): 3191-3200, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31515582

RESUMO

KEY MESSAGE: Genetic dissection uncovered a major QTL QTKW.caas-4BS corresponding with a 483 kb deletion that included genes ZnF, EamA and Rht-B1. This deletion was associated with increased grain weight and semi-dwarf phenotype. Previous studies identified quantitative trait loci (QTL) for thousand kernel weight (TKW) in the region spanning the Rht-B1 locus in wheat (Triticum aestivum L.). We recently mapped a major QTL QTKW.caas-4BS for TKW spanning the Rht-B1 locus in a recombinant inbred line (RIL) population derived from Doumai/Shi 4185 using the wheat 90K array. The allele from Doumai at QTKW.caas-4BS significantly increased TKW and kernel number per spike, and conferred semi-dwarf trait, which was beneficial to improve grain yield without a penalty to lodging. To further dissect QTKW.caas-4BS, we firstly re-investigated the genotypes and phenotypes of the RILs and confirmed the QTL using cleaved amplified polymorphic sequence (CAPS) markers developed from flanking SNP markers IWA102 and IWB54814. The target sequences of the CAPS markers were used as queries to BLAST the wheat reference genome RefSeq v1.0 and hit an approximate 10.4 Mb genomic region. Based on genomic mining and SNP loci from the wheat 660K SNP array in the above genomic region, we developed eight new markers and narrowed QTKW.caas-4BS to a genetic interval of 1.5 cM. A 483 kb deletion in Doumai corresponded with QTKW.caas-4BS genetically, including three genes ZnF, EamA and Rht-B1. The other 15 genes with either differential expressions and/or sequence variations between parents were also potential candidate genes for QTKW.caas-4BS. The findings not only provide a toolkit for marker-assisted selection of QTKW.caas-4BS but also defined candidate genes for further functional analysis.


Assuntos
Locos de Características Quantitativas , Sementes/fisiologia , Deleção de Sequência , Triticum/genética , Alelos , Mapeamento Cromossômico , Genes de Plantas , Marcadores Genéticos , Genótipo , Fenótipo , Polimorfismo de Nucleotídeo Único , Triticum/fisiologia
12.
Plant Sci ; 288: 110205, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31521217

RESUMO

Maize kernel size and weight are essential contributors to its yield. So the identification of the genes controlling kernel size and weight can give us a chance to gain the yield. Here, we identified a small kernel mutant, Zea mays small kernel 9 (Zmsmk9), in maize. Cytological observation showed that the development of the endosperm and embryo was delayed in Zmsmk9 mutants at the early stages, resulting in a small kernel phenotype. Interestingly, despite substantial variation in kernel size, the germination of Zmsmk9 seeds was comparable to that of WT, and could develop into normal plants with upright leaf architecture. We cloned Zmsmk9 via map-based cloning. ZmSMK9 encodes a P-type pentatricopeptide repeat protein that targets to mitochondria, and is involved in RNA splicing in mitochondrial NADH dehydrogenase5 (nad5) intron-1 and intron-4. Consistent with the delayed development phenotype, transcriptome analysis of 12-DAP endosperm showed that starch and zeins biosynthesis related genes were dramatically down regulated in Zmsmk9, while cell cycle and cell growth related genes were dramatically increased. As a result, ZmSMK9 is a novel gene required for the splicing of nad5 intron-1 and intron-4, kernel development, and plant architecture in maize.


Assuntos
Regulação da Expressão Gênica de Plantas , NADH Desidrogenase/genética , Proteínas de Plantas/genética , Zea mays/genética , Sequência de Aminoácidos , Perfilação da Expressão Gênica , Germinação/genética , Íntrons , Proteínas Mitocondriais/metabolismo , NADH Desidrogenase/química , NADH Desidrogenase/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Sementes/fisiologia , Zea mays/crescimento & desenvolvimento
13.
Plant Sci ; 288: 110232, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31521224

RESUMO

Seed coat is the tissue which establishes an interface between the seed inner tissues and external environment. Our group has shown that cowpea seed coat undergoes coordinated events of programmed cell death (PCD) during development. In relation to germinating seed coats, little is known on PCD events. The goal here was to investigate the biochemical aspects of germinating soybean seed coat, focusing on proteolytic activities related to PCD. In gel and in solution activity profiles of quiescent and germinating seed coat extracts revealed a complex pattern of caspase- and metacaspase-like cysteine protease activities. Trypsin inhibitor and reserve proteins were revealed as potential substrates for these proteases. A pancaspase inhibitor (z-VAD-CHO) affected the radicle length of seeds germinated under its presence. Ultrastructural analysis showed the absence of cell organelles in all seed coat layers after imbibition, while oligonucleosome fragments peaked at 72 h after imbibition (HAI). Altogether, the data suggest the presence of biochemical PCD hallmarks in germinating soybean seed coat and point to the involvement of the detected protease activities in processes such as reserve protein mobilization and weakening of seed coat.


Assuntos
Apoptose , Soja/fisiologia , Proteínas de Plantas/metabolismo , Sementes/fisiologia , Soja/enzimologia
14.
J Plant Physiol ; 241: 153031, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31476676

RESUMO

Seed dormancy is a critical mechanism that delays germination until environmental conditions are favorable for growth. Plant hormones gibberellin (GA) and abscisic acid (ABA) have long been recognized as key players in regulating dormancy and germination. Recent data have increased interest in brassinosteroid (BR) hormones that promote germination by activating GA downstream genes and inactivating ABA signaling. Exposure of imbibed seeds to low temperature (cold stratification) is widely used to release seed dormancy and to improve germination frequency. However, the mechanism by which cold stratification overcomes the inhibitory role of ABA is not completely understood. In the present study, we show delayed germination of seeds of the BR insensitive mutant, bri1-5, that was largely reversed by treatment with fluridone, an inhibitor of ABA biosynthesis. In addition, the bri1-5 seeds were markedly less sensitive to the cold stratification release of dormancy. These results suggest that BR locates upstream of ABA signaling and downstream of cold stratification signaling in dormancy and germination pathways. Consistent with this notion, BR biosynthetic genes, DWF4 and DET2, were upregulated by cold stratification. The transcripts of the GA biosynthesis gene, GA3ox1, and cold responsive genes, CBF1 and CBF2, increased in response to cold stratification in wild type seeds but not in bri1-5 seeds. Conversely, transgenic seeds overexpressing BRI1 germinated more rapidly than wild type in the absence of cold stratification. Thus, we propose that BR signaling plays a previously unrecognized role in the cold stratification pathway for seed dormancy and germination.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/fisiologia , Germinação/fisiologia , Dormência de Plantas/fisiologia , Proteínas Quinases/fisiologia , Ácido Abscísico/antagonistas & inibidores , Arabidopsis/crescimento & desenvolvimento , Temperatura Baixa , Escuridão , Germinação/efeitos dos fármacos , Luz , Piridonas/farmacologia , Sementes/fisiologia
15.
Phys Rev E ; 100(1-1): 013108, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31499848

RESUMO

Wind dispersal of seeds is an essential mechanism for plants to proliferate and to invade new territories. In this paper we present a methodology used in our recent work [Rabault, Fauli, and Carlson, Phys. Rev. Lett. 122, 024501 (2019PRLTAO0031-900710.1103/PhysRevLett.122.024501)] that combines 3D printing, a minimal theoretical model, and experiments to determine how the curvature along the length of the wings of autorotating seeds, fruits, and other diaspores provides them with an optimal wind dispersion potential, i.e., minimal terminal descent velocity. Experiments are performed on 3D-printed double-winged synthetic fruits for a wide range of wing fold angles (obtained from normalized curvature along the wing length), base wing angles, and wing loadings to determine how these affect the flight. Our experimental and theoretical models find an optimal wing fold angle that minimizes the descent velocity, where the curved wings must be sufficiently long to have horizontal segments, but also sufficiently short to ensure that their tip segments are primarily aligned along the horizontal direction. The curved shape of the wings of double winged autorotating diaspores may be an important parameter that improves the fitness of these plants in an ecological strategy.


Assuntos
Frutas/fisiologia , Modelos Biológicos , Dispersão Vegetal , Rotação , Sementes/fisiologia
16.
Plant Sci ; 287: 110185, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481205

RESUMO

HaHB11 is a sunflower transcription factor from the homeodomain-leucine zipper I family. Transgenic Arabidopsis plants expressing HaHB11 had larger rosettes and improved seed yield. In this work maize plants from hybrid HiII were transformed with 35S:HaHB11, ZmUBI:HaHB11 and ProHaHB11:HaHB11 and then backcrossed to B73 to obtain a more homozygous inbred phenotype. Transgene expression levels were stable at least during three generations. Greenhouse-grown HaHB11 transgenic lines had larger leaf area and delayed senescence than controls, together with increased total biomass (up to 25%) and seed yield (up to 28%). Field trials conducted with T2 and T4 generations indicated that enhanced leaf area (up to 18%), stem diameter (up to 28%) and total biomass (up to 40%) as well as delayed leaf senescence were maintained among transgenic individuals when upscaling from pots in the greenhouse to communal plants in the field. The T4 field-grown transgenic generation had increased light interception and radiation use efficiency as well as seed yield (43-47% for events driven by the 35S promoter). Results suggest that HaHB11 is a promising tool for crop improvement because differential traits observed in the Arabidopsis model plant were preserved in a crop like maize independently of growth conditions and backcross level.


Assuntos
Helianthus/genética , Fatores de Transcrição/metabolismo , Zea mays/fisiologia , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Biomassa , Zíper de Leucina , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Fatores de Transcrição/genética , Transgenes , Zea mays/genética , Zea mays/crescimento & desenvolvimento
17.
Plant Mol Biol ; 101(4-5): 471-486, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31552586

RESUMO

KEY MESSAGE: Subgroup IVc basic helix-loop-helix transcription factors OsbHLH058 and OsbHLH059 positively regulate major iron deficiency responses in rice in a similar but distinct manner, putatively under partial control by OsHRZs. Under low iron availability, plants transcriptionally induce the expression of genes involved in iron uptake and translocation. OsHRZ1 and OsHRZ2 ubiquitin ligases negatively regulate this iron deficiency response in rice. The basic helix-loop-helix (bHLH) transcription factor OsbHLH060 interacts with OsHRZ1, and positively regulates iron deficiency-inducible genes. However, the functions of three other subgroup IVc bHLH transcription factors in rice, OsbHLH057, OsbHLH058, and OsbHLH059, have not yet been characterized. In the present study, we investigated the functions of OsbHLH058 and OsbHLH059 related to iron deficiency response. OsbHLH058 expression was repressed under iron deficiency, whereas the expression of OsbHLH057 and OsbHLH060 was moderately induced. Yeast two-hybrid analysis indicated that OsbHLH058 interacts with OsHRZ1 and OsHRZ2 more strongly than OsbHLH060, whereas OsbHLH059 showed no interaction. An in vitro ubiquitination assay detected no OsbHLH058 and OsbHLH060 ubiquitination by OsHRZ1 and OsHRZ2. Transgenic rice lines overexpressing OsbHLH058 showed tolerance for iron deficiency and higher iron concentration in seeds. These lines also showed enhanced expression of many iron deficiency-inducible genes involved in iron uptake and translocation under iron-sufficient conditions. Conversely, OsbHLH058 knockdown lines showed susceptibility to iron deficiency and reduced expression of many iron deficiency-inducible genes. OsbHLH059 knockdown lines were also susceptible to iron deficiency, and formed characteristic brownish regions in iron-deficient new leaves. OsbHLH059 knockdown lines also showed reduced expression of many iron deficiency-inducible genes. These results indicate that OsbHLH058 and OsbHLH059 positively regulate major iron deficiency responses in a similar but distinct manner, and that this function may be partially controlled by OsHRZs.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas , Ferro/deficiência , Oryza/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Expressão Gênica , Técnicas de Silenciamento de Genes , Oryza/fisiologia , Folhas de Planta/genética , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Sementes/genética , Sementes/fisiologia
18.
Planta ; 250(5): 1717-1729, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31414204

RESUMO

MAIN CONCLUSION: Seed-processing technologies such as polishing and washing enhance crop seed quality by limited removal of the outer layers and by leaching. Combined, this removes chemical compounds that inhibit germination. Industrial processing to deliver high-quality commercial seed includes removing chemical inhibitors of germination, and is essential to produce fresh sprouts, achieve vigorous crop establishment, and high yield potential in the field. Sugar beet (Beta vulgaris subsp. vulgaris var. altissima Doell.), the main sugar source of the temperate agricultural zone, routinely undergoes several processing steps during seed production to improve germination performance and seedling growth. Germination assays and seedling phenotyping was carried out on unprocessed, and processed (polished and washed) sugar beet fruits. Pericarp-derived solutes, known to inhibit germination, were tested in germination assays and their osmolality and conductivity assessed (ions). Abscisic acid (ABA) and ABA metabolites were quantified in both the true seed and pericarp tissue using UPLC-ESI(+)-MS/MS. Physical changes in the pericarp structures were assessed using scanning electron microscopy (SEM). We found that polishing and washing of the sugar beet fruits both had a positive effect on germination performance and seedling phenotype, and when combined, this positive effect was stronger. The mechanical action of polishing removed the outer pericarp (fruit coat) tissue (parenchyma), leaving the inner tissue (sclerenchyma) unaltered, as revealed by SEM. Polishing as well as washing removed germination inhibitors from the pericarp, specifically, ABA, ABA metabolites, and ions. Understanding the biochemistry underpinning the effectiveness of these processing treatments is key to driving further innovations in commercial seed quality.


Assuntos
Ácido Abscísico/metabolismo , Beta vulgaris/crescimento & desenvolvimento , Reguladores de Crescimento de Planta/metabolismo , Beta vulgaris/fisiologia , Bioquímica , Germinação , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Espectrometria de Massas em Tandem
19.
Theor Appl Genet ; 132(11): 3079-3087, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31367839

RESUMO

KEY MESSAGE: This paper combined GWAS, meta-analysis and sequence homology comparison with common bean to identify regions associated with seed size variation in domesticated cowpea. Seed size is an important trait for yield and commercial value in dry-grain cowpea. Seed size varies widely among different cowpea accessions, and the genetic basis of such variation is not yet well understood. To better decipher the genetic basis of seed size, a genome-wide association study (GWAS) and meta-analysis were conducted on a panel of 368 cowpea diverse accessions from 51 countries. Four traits, including seed weight, length, width and density were evaluated across three locations. Using 51,128 single nucleotide polymorphisms covering the cowpea genome, 17 loci were identified for these traits. One locus was common to weight, width and length, suggesting pleiotropy. By integrating synteny-based analysis with common bean, six candidate genes (Vigun05g036000, Vigun05g039600, Vigun05g204200, Vigun08g217000, Vigun11g187000, and Vigun11g191300) which are implicated in multiple functional categories related to seed size such as endosperm development, embryo development, and cell elongation were identified. These results suggest that a combination of GWAS meta-analysis with synteny comparison in a related plant is an efficient approach to identify candidate gene (s) for complex traits in cowpea. The identified loci and candidate genes provide useful information for improving cowpea varieties and for molecular investigation of seed size.


Assuntos
Sementes/fisiologia , Vigna/genética , Mapeamento Cromossômico , Genes de Plantas , Estudos de Associação Genética , Genótipo , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Vigna/fisiologia
20.
BMC Plant Biol ; 19(1): 308, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31299895

RESUMO

BACKGROUND: Land preparation is an important component of fragrant rice production. However, the effect of tillage on fragrant rice production is unclear, especially regarding the biosynthesis of 2-acetyl-1-pyrroline (2-AP), which is the main compound of the unique aroma of fragrant rice. This study aimed to explore 2-AP biosynthesis in fragrant rice under different tillage regimes. Three tillage methods were applied in the present study: conventional rotary tillage (CK) as the control, plough tillage (PT), and no-tillage (NT). RESULT: Compared with CK, the PT treatment increased 2-AP content in grain, upregulated the activity of ornithine aminotransferase (OAT) and increased contents of 1-pyrroline and pyrroline-5-carboxylic acid (P5C). Furthermore, the PT treatment increased the grain yield and nitrogen accumulation of fragrant rice. Meanwhile, the 2-AP content in the grain produced under the NT treatment was significantly higher than that in the grain produced under both the PT and CK treatments due to the enhancement of proline content and the activities of proline dehydrogenase (PDH) and △1-pyrroline-5-carboxylic acid synthetase (P5CS). However, the present study observed that the overall production of fragrant rice under NT conditions was inferior due to lower yield, nitrogen accumulation, and anti-oxidative enzymatic activities. Moreover, the organic matter content and soil microorganism quantity increased due to PT and NT treatments. CONCLUSIONS: Compared to CK, PT improved fragrant rice grain yield and nitrogen accumulation and induced an increase in OAT activity and led to an increase in 2-AP concentration. No-tillage also produced increased 2-AP content in grain by enhancing PDH and P5CS activities but limited yields and nitrogen accumulation in fragrant rice.


Assuntos
Oryza/fisiologia , Prolina Oxidase/metabolismo , Pirróis/metabolismo , Odorantes , Oryza/enzimologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Prolina/análise , Prolina Oxidase/genética , Sementes/enzimologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/fisiologia
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