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1.
PLoS One ; 15(9): e0238179, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881902

RESUMO

Carotenoid cleavage dioxygenase (CCD), a key enzyme in carotenoid metabolism, cleaves carotenoids to form apo-carotenoids, which play a major role in plant growth and stress responses. CCD genes had not previously been systematically characterized in Brassica napus (rapeseed), an important oil crop worldwide. In this study, we identified 30 BnCCD genes and classified them into nine subgroups based on a phylogenetic analysis. We identified the chromosomal locations, gene structures, and cis-promoter elements of each of these genes and performed a selection pressure analysis to identify residues under selection. Furthermore, we determined the subcellular localization, physicochemical properties, and conserved protein motifs of the encoded proteins. All the CCD proteins contained a retinal pigment epithelial membrane protein (RPE65) domain. qRT-PCR analysis of expression of 20 representative BnCCD genes in 16 tissues of the B. napus cultivar Zhong Shuang 11 ('ZS11') revealed that members of the BnCCD gene family possess a broad range of expression patterns. This work lays the foundation for functional studies of the BnCCD gene family.


Assuntos
Brassica napus/enzimologia , Dioxigenases/genética , Genoma de Planta , Proteínas de Plantas/genética , Arabidopsis/enzimologia , Brassica napus/genética , Carotenoides/metabolismo , Mapeamento Cromossômico , Dioxigenases/classificação , Dioxigenases/metabolismo , Regulação da Expressão Gênica de Plantas , Família Multigênica , Filogenia , Proteínas de Plantas/classificação , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas
2.
Gene ; 747: 144674, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32304781

RESUMO

Very long chain fatty acids (VLCFAs) that are structural components of cell membrane lipid, cuticular waxes and seed oil, play crucial roles in plant growth, development and stress response. Fatty acid elongases (FAEs) comprising KCS and ELO, are key enzymes for VLCFA biosynthesis in plants. Although reference genomes of Brassica napus and its parental speices both have been sequenced, whole-genome analysis of FAE gene family in these Brassica speices is not reported. Here, 58, 33 and 30 KCS genes were identified in B. napus, B. rapa and B. oleracea genomes, respectively, whereas 14, 6 and 8 members were obtained for ELO genes. These KCS genes were unevenly located in 37 chromosomes and 3 scaffolds of 3 Brassica species, while these ELO genes were mapped to 19 chromosomes. The KCS and ELO proteins were divided into 8 and 4 subclasses, respectively. Gene structure and protein motifs remained highly conserved in each KCS or ELO subclass. Most promoters of KCS and ELO genes harbored various plant growth-, phytohormone-, and stress response-related cis-acting elements. 20 SSR loci existed in the KCS and ELO genes/promoters. The whole-genome duplication and segmental duplication mainly contributed to expansion of KCS and ELO genes in these genomes. Transcriptome analysis showed that KCS and ELO genes in 3 Brassica species were expressed in various tissues/organs with different levels, whereas 1 BnELO gene and 6 BnKCS genes might be pathogen-responsive genes. The qRT-PCR assay showed that BnKCS22 and BnELO04 responded to various phytohormone treatments and abiotic stresses. This work lays the foundation for further function identification of KCS and ELO genes in B. napus and its progenitors.


Assuntos
Brassica napus/enzimologia , Brassica napus/genética , Elongases de Ácidos Graxos/genética , Genes de Plantas , Estudo de Associação Genômica Ampla , Família Multigênica , Brassica napus/efeitos dos fármacos , Cromossomos de Plantas/genética , Sequência Conservada/genética , Duplicação Gênica , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Loci Gênicos , Repetições de Microssatélites/genética , Motivos de Nucleotídeos , Filogenia , Reguladores de Crescimento de Planta/farmacologia , Sequências Reguladoras de Ácido Nucleico/genética , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Sintenia/genética
3.
Ecotoxicol Environ Saf ; 197: 110613, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32304923

RESUMO

Cadmium (Cd) contaminated soil has threatened plant growth and human health. Rapeseed (Brassica napus L.), an ideal plant for phytoremediation, is an important source of edible vegetable oil, vegetable, animal fodder, green manure and biodiesel. For safe utilization of Cd polluted soil, physiological, biochemical, and molecular techniques have been used to understand mechanisms of Cd tolerance in B. napus. However, most of these researches have concentrated on vegetative and adult stages, just a few reports focus on the initial growth stage. Here, the partitioning of cadmium, gene expression level and activity of enzymatic antioxidants of H18 (tolerant genotype) and P9 (sensitive genotype) were investigated under 0 and 30 mg/L Cd stress at seedling establishment stage. Results shown that the radicle length of H18 and P9 under Cd stress were decreased by 30.33 (0.01 < P < 0.05) and 88.89% (P < 0.01) respectively. Cd concentration at cotyledon not radicle and hypocotyl in P9 was significantly higher than that in H18. The expression level of BnaHMA4c, which plays a key role in root-to-shoot translocation of Cd, was extremely higher in P9 than in H18 under both normal and Cd stress conditions. We also found that SOD, CAT and POD were more active in responding to Cd stress after 48 h, and the activity of SOD and CAT in H18 were higher than that in P9 at all observed time points. In conclusion, high activity of enzymatic antioxidants at initial Cd stress stage is the main detoxification mechanism in Cd-tolerant rapeseed, while the higher Cd transfer coefficient, driven by higher expression level of BnaHMA4c is the main mechanism for surviving radicle from initial Cd toxicity in Cd-sensitive rapeseed.


Assuntos
Brassica napus/efeitos dos fármacos , Cádmio/toxicidade , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Biodegradação Ambiental , Brassica napus/enzimologia , Brassica napus/crescimento & desenvolvimento , Cádmio/farmacocinética , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/crescimento & desenvolvimento , Poluentes do Solo/farmacocinética
4.
Plant Biol (Stuttg) ; 22(4): 679-690, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32003103

RESUMO

Melatonin has emerged as an essential molecule in plants, due to its role in defence against metal toxicity. Aluminium (Al) and cadmium (Cd) toxicity inhibit rapeseed seedling growth. In this study, we applied different doses of melatonin (50 and 100 µm) to alleviate Al (25 µm) and Cd (25 µm) stress in rapeseed seedlings. Results show that Al and Cd caused toxicity in rapeseed seedling, as evidenced by a decrease in height, biomass and antioxidant enzyme activity. Melatonin increased the expression of melatonin biosynthesis-related Brassica napus genes for caffeic acid O-methyl transferase (BnCOMT) under Al and Cd stress. The genes BnCOMT-1, BnCOMT-5 and BnCOMT-8 showed up-regulated expression, while BnCOMT-4 and BnCOMT-6 were down-regulated during incubation in water. Melatonin application increased the germination rate, shoot length, root length, fresh and dry weight of seedlings. Melatonin supplementation under Al and Cd stress increased superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, proline, chlorophyll and anthocyanin content, as well as photosynthesis rate. Both Cd and Al treatments significantly increased hydrogen peroxide and malondialdehyde levels in rapeseed seedlings, which were strictly counterbalanced by melatonin. Analysis of Cd and Al in different subcellular compartments showed that melatonin enhanced cell wall and soluble fractions, but reduced the vacuolar and organelle fractions in Al- and Cd-treated seedlings. These results suggest that melatonin-induced improvements in antioxidant potential, biomass, photosynthesis rate and successive Cd and Al sequestration play a pivotal role in plant tolerance to Al and Cd stress. This mechanism may have potential implications in safe food production.


Assuntos
Alumínio , Brassica napus , Cádmio , Regulação da Expressão Gênica de Plantas , Melatonina , Alumínio/toxicidade , Antioxidantes/farmacologia , Brassica napus/efeitos dos fármacos , Brassica napus/enzimologia , Cádmio/toxicidade , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Melatonina/farmacologia , Oxirredutases/genética , Oxirredutases/metabolismo , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/crescimento & desenvolvimento , Poluentes do Solo/toxicidade
5.
Plant Physiol Biochem ; 147: 101-112, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31855816

RESUMO

Plant phospholipase A (PLA) and C (PLC) families are least explored in terms of structure, diversity and their roles in membrane lipid remodeling under stress conditions. In this study, we performed gene family analysis, determined gene expression in different tissues and monitored transcriptional regulation of patatin-related PLA family and PLC family in oil crop Brassica napus under dehydration, salt, abscisic acid and cold stress. The identified 29 BnapPLA genes and 40 BnaPLC genes shared high similarities with Arabidopsis pPLAs and PLCs, respectively. This study highlighted the expression pattern of BnapPLAs and BnaPLCs in different tissues and their expression in response to abiotic stresses in Brassica napus. The results revealed that several members of BnapPLA3, PI-PLC1/2 and NPC1 were actively regulated by abiotic stresses. Lipid changes at different time points under stress conditions were also measured. Lipid profiling revealed that the level of lysophospholipids and diacylglycerol (DAG) showed a varied pattern of changes under different abiotic stress treatments. The change of lipids correlated with the transcriptional regulation of a few specific members of pPLA and PLC families. Our study suggested that A and C-type phospholipases in Brassica napus may have diverse physiological and regulatory roles in abiotic stress response and tolerance.


Assuntos
Brassica napus , Fosfolipases A , Proteínas de Plantas , Estresse Fisiológico , Fosfolipases Tipo C , Brassica napus/enzimologia , Brassica napus/genética , Diglicerídeos/metabolismo , Estudo de Associação Genômica Ampla , Metabolismo dos Lipídeos/genética , Fosfolipases A/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética , Fosfolipases Tipo C/genética
6.
Int J Mol Sci ; 20(22)2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31731804

RESUMO

Fructose-1,6-bisphosphate aldolase (FBA) is a versatile metabolic enzyme involved in multiple important processes of glycolysis, gluconeogenesis, and Calvin cycle. Despite its significance in plant biology, the identity of this gene family in oil crops is lacking. Here, we performed genome-wide identification and characterization of FBAs in an allotetraploid species, oilseed rape Brassica napus. Twenty-two BnaFBA genes were identified and divided into two groups based on integrative analyses of functional domains, phylogenetic relationships, and gene structures. Twelve and ten B. napus FBAs (BnaFBAs) were predicted to be localized in the chloroplast and cytoplasm, respectively. Notably, synteny analysis revealed that Brassica-specific triplication contributed to the expansion of the BnaFBA gene family during the evolution of B. napus. Various cis-acting regulatory elements pertinent to abiotic and biotic stresses, as well as phytohormone responses, were detected. Intriguingly, each of the BnaFBA genes exhibited distinct sequence polymorphisms. Among them, six contained signatures of selection, likely having experienced breeding selection during adaptation and domestication. Importantly, BnaFBAs showed diverse expression patterns at different developmental stages and were preferentially highly expressed in photosynthetic tissues. Our data thus provided the foundation for further elucidating the functional roles of individual BnaFBA and also potential targets for engineering to improve photosynthetic productivity in B. napus.


Assuntos
Brassica napus/enzimologia , Frutose-Bifosfato Aldolase/metabolismo , Proteínas de Plantas/metabolismo , Brassica napus/genética , Frutose-Bifosfato Aldolase/genética , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Plantas/genética , Poliploidia
7.
Plant Physiol ; 181(4): 1468-1479, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31619508

RESUMO

In most oilseeds, two evolutionarily unrelated acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes, DGAT1 and DGAT2, are the main contributors to the acylation of diacylglycerols in the synthesis of triacylglycerol. DGAT1 and DGAT2 are both present in the important crop oilseed rape (Brassica napus), with each type having four isoforms. We studied the activities of DGAT isoforms during seed development in microsomal fractions from two oilseed rape cultivars: edible, low-erucic acid (22:1) MONOLIT and nonedible high-erucic acid MAPLUS. Whereas the specific activities of DGATs were similar with most of the tested acyl-CoA substrates in both cultivars, MAPLUS had 6- to 14-fold higher activity with 22:1-CoA than did MONOLIT. Thus, DGAT isoforms with different acyl-CoA specificities are differentially active in the two cultivars. We characterized the acyl-CoA specificities of all DGAT isoforms in oilseed rape in the microsomal fractions of yeast cells heterologously expressing these enzymes. All four DGAT1 isoforms showed similar and broad acyl-CoA specificities. However, DGAT2 isoforms had much narrower acyl-CoA specificities: two DGAT2 isoforms were highly active with 22:1-CoA, while the ability of the other two isoforms to use this substrate was impaired. These findings elucidate the importance, which a DGAT isoform with suitable acyl-CoA specificity may have, when aiming for high content of a particular fatty acid in plant triacylglycerol reservoirs.


Assuntos
Acil Coenzima A/metabolismo , Brassica napus/enzimologia , Diacilglicerol O-Aciltransferase/metabolismo , Ácidos Erúcicos/metabolismo , Proteínas de Plantas/metabolismo , Brassica napus/genética , Diacilglicerol O-Aciltransferase/genética , Regulação da Expressão Gênica de Plantas , Isoenzimas/genética , Isoenzimas/metabolismo , Microssomos/enzimologia , Filogenia , Proteínas de Plantas/genética , Sementes/embriologia , Especificidade por Substrato/genética , Triglicerídeos
8.
Plant Mol Biol ; 101(3): 325-339, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31399934

RESUMO

KEY MESSAGE: Combining genetic engineering of MPK4 activity and quantitative proteomics, we established an in planta system that enables rapid study of MPK4 signaling networks and potential substrate proteins. Mitogen activated protein kinase 4 (MPK4) is a multifunctional kinase that regulates various signaling events in plant defense, growth, light response and cytokinesis. The question of how a single protein modulates many distinct processes has spurred extensive research into the physiological outcomes resulting from genetic perturbation of MPK4. However, the mechanism by which MPK4 functions is still poorly understood due to limited data on the MPK4 networks including substrate proteins and downstream pathways. Here we introduce an experimental system that combines genetic engineering of kinase activity and quantitative proteomics to rapidly study the signaling networks of MPK4. First, we transiently expressed a constitutively active (MPK4CA) and an inactive (MPK4IN) version of a Brassica napus MPK4 (BnMPK4) in Nicotiana benthamiana leaves. Proteomics analysis revealed that BnMPK4 activation affects multiple pathways (e.g., metabolism, redox regulation, jasmonic acid biosynthesis and stress responses). Furthermore, BnMPK4 activation also increased protein phosphorylation in the phosphoproteome, from which putative MPK4 substrates were identified. Using protein kinase assay, we validated that a transcription factor TCP8-like (TCP8) and a PP2A regulatory subunit TAP46-like (TAP46) were indeed phosphorylated by BnMPK4. Taken together, we demonstrated the utility of proteomics and phosphoproteomics in elucidating kinase signaling networks and in identification of downstream substrates.


Assuntos
Regulação da Expressão Gênica de Plantas , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteômica , Arabidopsis , Proteínas de Arabidopsis/metabolismo , Brassica napus/enzimologia , Engenharia Genética , Sistema de Sinalização das MAP Quinases , Fosforilação , Imunidade Vegetal , Folhas de Planta/enzimologia , Proteoma , Transdução de Sinais , Tabaco/enzimologia
9.
New Phytol ; 224(2): 700-711, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31400160

RESUMO

Lysophosphatidate acyltransferase (LPAAT) catalyses the second step of the Kennedy pathway for triacylglycerol (TAG) synthesis. In this study we expressed Trapaeolum majus LPAAT in Brassica napus (B. napus) cv 12075 to evaluate the effects on lipid synthesis and estimate the flux control coefficient for LPAAT. We estimated the flux control coefficient of LPAAT in a whole plant context by deriving a relationship between it and overall lipid accumulation, given that this process is a exponential. Increasing LPAAT activity resulted in greater TAG accumulation in seeds of between 25% and 29%; altered fatty acid distributions in seed lipids (particularly those of the Kennedy pathway); and a redistribution of label from 14 C-glycerol between phosphoglycerides. Greater LPAAT activity in seeds led to an increase in TAG content despite its low intrinsic flux control coefficient on account of the exponential nature of lipid accumulation that amplifies the effect of the small flux increment achieved by increasing its activity. We have also developed a novel application of metabolic control analysis likely to have broad application as it determines the in planta flux control that a single component has upon accumulation of storage products.


Assuntos
Aciltransferases/metabolismo , Brassica napus/enzimologia , Sementes/química , Triglicerídeos/metabolismo , Aciltransferases/genética , Brassica napus/metabolismo , DNA de Plantas , Regulação Enzimológica da Expressão Gênica/fisiologia , Regulação da Expressão Gênica de Plantas/fisiologia , Plantas Geneticamente Modificadas , Triglicerídeos/química , Tropaeolum/enzimologia , Tropaeolum/genética
10.
Plant Cell ; 31(10): 2370-2385, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31439805

RESUMO

Identifying genetic variation that increases crop yields is a primary objective in plant breeding. We used association analyses of oilseed rape/canola (Brassica napus) accessions to identify genetic variation that influences seed size, lipid content, and final crop yield. Variation in the promoter region of the HECT E3 ligase gene BnaUPL3 C03 made a major contribution to variation in seed weight per pod, with accessions exhibiting high seed weight per pod having lower levels of BnaUPL3 C03 expression. We defined a mechanism in which UPL3 mediated the proteasomal degradation of LEC2, a master transcriptional regulator of seed maturation. Accessions with reduced UPL3 expression had increased LEC2 protein levels, larger seeds, and prolonged expression of lipid biosynthetic genes during seed maturation. Natural variation in BnaUPL3 C03 expression appears not to have been exploited in current B napus breeding lines and could therefore be used as a new approach to maximize future yields in this important oil crop.


Assuntos
Brassica napus/metabolismo , Produtos Agrícolas/metabolismo , Proteínas de Plantas/metabolismo , Sementes/metabolismo , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brassica napus/enzimologia , Brassica napus/genética , Produtos Agrícolas/química , Produtos Agrícolas/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Homeodomínio/metabolismo , Ligases/genética , Ligases/metabolismo , Metabolismo dos Lipídeos/genética , Metabolismo dos Lipídeos/fisiologia , Mutação , Fenótipo , Mucilagem Vegetal/biossíntese , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Óleo de Brassica napus/metabolismo , Sementes/química , Sementes/genética , Sementes/crescimento & desenvolvimento , Fatores de Transcrição/genética , Transcriptoma/genética , Ubiquitina-Proteína Ligases/genética
11.
Int J Mol Sci ; 20(13)2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31284391

RESUMO

Self-incompatibility (SI) is a widespread mechanism in angiosperms that prevents inbreeding by rejecting self-pollen. However, the regulation of the SI response in Brassica napus is not well understood. Here, we report that the M-locus protein kinase (MLPK) BnaMLPKs, the functional homolog of BrMLPKs in Brassica rapa, controls SI in B. napus. We identified four paralogue MLPK genes in B. napus, including BnaA3.MLPK, BnaC3.MLPK, BnaA4.MLPK, and BnaC4.MLPK. Two transcripts of BnaA3.MLPK, BnaA3.MLPKf1 and BnaA3.MLPKf2, were generated by alternative splicing. Tissue expression pattern analysis demonstrated that BnaA3.MLPK, especially BnaA3.MLPKf2, is highly expressed in reproductive organs, particularly in stigmas. We subsequently created RNA-silencing lines and CRISPR/Cas9-induced quadruple mutants of BnaMLPKs in B. napus SI line S-70. Phenotypic analysis revealed that SI response is partially suppressed in RNA-silencing lines and is completely blocked in quadruple mutants. These results indicate the importance of BnaMLPKs in regulating the SI response of B. napus. We found that the expression of SI positive regulators S-locus receptor kinase (SRK) and Arm-Repeat Containing 1 (ARC1) are suppressed in bnmlpk mutant, whereas the self-compatibility (SC) element Glyoxalase I (GLO1) maintained a high expression level. Overall, our findings reveal a new regulatory mechanism of MLPK in the SI of B. napus.


Assuntos
Brassica napus/enzimologia , Brassica napus/fisiologia , Proteína Quinase C/metabolismo , Autoincompatibilidade em Angiospermas/fisiologia , Sequência de Aminoácidos , Sequência de Bases , Brassica napus/genética , Sistemas CRISPR-Cas/genética , Edição de Genes , Regulação da Expressão Gênica de Plantas , Mutação/genética , Especificidade de Órgãos/genética , Filogenia , Plantas Geneticamente Modificadas , Polinização , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteína Quinase C/química , Proteína Quinase C/genética , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
12.
Int J Mol Sci ; 20(13)2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31284614

RESUMO

We examined the substrate preference of Cuphea paucipetala acyl-ACP thioesterases, CpFatB4 and CpFatB5, and gene expression changes associated with the modification of lipid composition in the seed, using Brassica napus transgenic plants overexpressing CpFatB4 or CpFatB5 under the control of a seed-specific promoter. CpFatB4 seeds contained a higher level of total saturated fatty acid (FA) content, with 4.3 times increase in 16:0 palmitic acid, whereas CpFatB5 seeds showed approximately 3% accumulation of 10:0 and 12:0 medium-chain FAs, and a small increase in other saturated FAs, resulting in higher levels of total saturated FAs. RNA-Seq analysis using entire developing pods at 8, 25, and 45 days after flowering (DAF) showed up-regulation of genes for ß-ketoacyl-acyl carrier protein synthase I/II, stearoyl-ACP desaturase, oleate desaturase, and linoleate desaturase, which could increase unsaturated FAs and possibly compensate for the increase in 16:0 palmitic acid at 45 DAF in CpFatB4 transgenic plants. In CpFatB5 transgenic plants, many putative chloroplast- or mitochondria-encoded genes were identified as differentially expressed. Our results report comprehensive gene expression changes induced by alterations of seed FA composition and reveal potential targets for further genetic modifications.


Assuntos
Brassica napus/enzimologia , Brassica napus/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Sementes/enzimologia , Sementes/genética , Tioléster Hidrolases/genética , Brassica napus/crescimento & desenvolvimento , Ontologia Genética , Genes de Plantas , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Tioléster Hidrolases/metabolismo , Transcriptoma/genética
13.
J Plant Physiol ; 240: 153007, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31310905

RESUMO

Previous studies have proven that graphene oxide (GO) regulates abscisic acid (ABA) and indole-3-acetic acid (IAA) contents and modulates plant root growth. To better understand the mechanism of plant growth and development regulated by GO and crosstalk between ABA and GO, Zhongshuang No. 9 seedlings were treated with GO and ABA. The results indicated that GO and ABA significantly affected the morphological properties and endogenous phytohormone contents in seedlings, and there was significant crosstalk between GO and ABA. ABA treatments combined with GO led to a rapid decrease in triphenyltetrazolium chloride (TTC) reduction intensity, and the inhibitory effect was enhanced with increasing ABA concentration. The treatments significantly affected the transcriptional levels of some key genes involved in the ABA, IAA, cytokinin (CTK), salicylic acid (SA), and ethane (ETH) pathways and increased the ABA and gibberellin (GA) contents in rapeseed seedlings. The effects of the treatments on the IAA and CTK contents were complex, but, importantly, the treatments suppressed root elongation. Correlation analysis also indicated that the relationship between root length and IAA/ABA could be described by a polynomial function: y = 88.11x2 - 25.15x + 4.813(R²â€¯= 0.912). The treatments increased the ACS2 transcript abundance for ETH biosynthesis and the ICS1 transcriptional level of the key genes involved in salicylic acid (SA) biosynthesis, as well as the downstream signaling genes CBP60 and SARD1. This finding indicated that ABA is an important factor regulating the effects of GO on the growth and development of Brassica napus L., and that ETH and SA pathways may be potential pathways involved in the response of rape seedlings to GO treatment.


Assuntos
Ácido Abscísico/administração & dosagem , Brassica napus/crescimento & desenvolvimento , Grafite/administração & dosagem , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Planta , Ácido Abscísico/metabolismo , Brassica napus/efeitos dos fármacos , Brassica napus/enzimologia , Brassica napus/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo
14.
Sci Rep ; 9(1): 9196, 2019 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-31235772

RESUMO

Glutathione transferases (GSTs) are multifunctional enzymes that play important roles in plant development and responses to biotic and abiotic stress. However, a systematic analysis of GST family members in Brassica napus has not yet been reported. In this study, we identified 179 full-length GST genes in B. napus, 44.2% of which are clustered on various chromosomes. In addition, we identified 141 duplicated GST gene pairs in B. napus. Molecular evolutionary analysis showed that speciation and whole-genome triplication played important roles in the divergence of the B. napus GST duplicated genes. Transcriptome analysis of 21 tissues at different developmental stages showed that 47.6% of duplicated GST gene pairs have divergent expression patterns, perhaps due to structural divergence. We constructed a GST gene coexpression network with genes encoding various transcription factors (NAC, MYB, WRKY and bZIP) and identified six modules, including genes expressed during late seed development (after 40 days; BnGSTU19, BnGSTU20 and BnGSTZ1) and in the seed coat (BnGSTF6 and BnGSTF12), stamen and anther (BnGSTF8), root and stem (BnGSTU21), leaves and funiculus, as well as during the late stage of pericarp development (after 40 days; BnGSTU12 and BnGSTF2) and in the radicle during seed germination (BnGSTF14, BnGSTU1, BnGSTU28, and BnGSTZ1). These findings lay the foundation for elucidating the roles of GSTs in B. napus.


Assuntos
Brassica napus/genética , Genes Duplicados , Genes de Plantas , Glutationa Transferase/genética , Estresse Fisiológico/genética , Brassica napus/enzimologia , Duplicação Gênica , Regulação da Expressão Gênica de Plantas , Família Multigênica , Proteínas de Plantas/genética
15.
Sci Rep ; 9(1): 9368, 2019 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-31249367

RESUMO

Cyclophilins (CYPs) are a group of ubiquitous prolyl cis/trans isomerases (PPIases). It was shown that plants possess the most diverse CYP families and that these are abundant in the phloem long-distance translocation stream. Since phloem exudate showed PPIase activity, three single-domain CYPs that occur in phloem samples from Brassica napus were characterised on functional and structural levels. It could be shown that they exhibit isomerase activity and that this activity is controlled by a redox regulation mechanism, which has been postulated for divergent CYPs. The structure determination by small-angle X-ray scattering experiments revealed a conserved globular shape. In addition, the high-resolution crystal structure of BnCYP19-1 was resolved and refined to 2.0 Å resolution, and the active sites of related CYPs as well as substrate binding were modelled. The obtained data and results support the hypothesis that single domain phloem CYPs are active phloem PPIases that may function as chaperones.


Assuntos
Brassica napus/enzimologia , Ciclofilinas/química , Ciclofilinas/metabolismo , Floema/enzimologia , Domínios Proteicos , Sequência de Aminoácidos , Sítios de Ligação , Domínio Catalítico , Ativação Enzimática , Cinética , Modelos Moleculares , Oxirredução , Conformação Proteica , Relação Estrutura-Atividade
16.
Nanoscale ; 11(21): 10511-10523, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31116204

RESUMO

Although there have been some studies on the plant-carbonaceous nanomaterials (CNMs) interactions, related conclusions were controversial. Here, we report that multi-walled carbon nanotubes (MWCNTs) can enter into rapeseed (Brassica napus L.) seedling root, and transport to stem. Further results showed that salinity-inhibited rapeseed seedling growth was obviously alleviated by MWCNTs. Meanwhile, NaCl-induced nitrate reductase (NR)-dependent NO production was significantly intensified by MWCNTs. The redox and ion imbalance was reestablished as well, confirmed by the reduction in reactive oxygen species (ROS) overproduction, the decrease in thiobarbituric acid reactive substance production, and the lower Na+/K+ ratio. These beneficial effects could be explained by the changes in related antioxidant defense genes, sodium hydrogen exchanger 1 (NHX1), salt overly sensitive 1 (SOS1), and K+transporter 1 (KT1) transcripts. The above responses were separately abolished after the removal of endogenous NO with its scavengers or the addition of the NR inhibitor. Genetic evidence revealed that the NaCl-triggered NO level in wild-type seedling roots was partly abolished in either the nitric reductase mutant (nia1/2) or noa1 mutant (exhibiting indirectly a reduced endogenous NO level). Treatment with MWCNTs could totally rescue the impaired NO production in the noa1 mutant rather than the nia1/2 mutant, suggesting that NR-dependent NO acts as a downstream signaling molecule in MWCNT signaling. This point was verified by phenotypic analyses, histochemical staining, and ion analysis. qPCR analysis further demonstrated that MWCNTs stimulated antioxidant genes and ion balance-related genes through NR-mediated NO. The above molecular and genetic evidence indicated that NR-dependent NO acts downstream of MWCNTs in salinity tolerance, which requires the reestablishment of redox and ion homeostasis.


Assuntos
Brassica napus/enzimologia , Nanotubos de Carbono/química , Nitrato Redutase/metabolismo , Óxido Nítrico/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Tolerância ao Sal/efeitos dos fármacos , Plântula/enzimologia , Brassica napus/genética , Nitrato Redutase/genética , Óxido Nítrico/genética , Proteínas de Plantas/genética , Raízes de Plantas/genética , Salinidade , Plântula/genética , Transdução de Sinais
17.
Molecules ; 24(10)2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31126120

RESUMO

Lignin is an important biological polymer in plants that is necessary for plant secondary cell wall ontogenesis. The laccase (LAC) gene family catalyzes lignification and has been suggested to play a vital role in the plant kingdom. In this study, we identified 45 LAC genes from the Brassica napus genome (BnLACs), 25 LAC genes from the Brassica rapa genome (BrLACs) and 8 LAC genes from the Brassica oleracea genome (BoLACs). These LAC genes could be divided into five groups in a cladogram and members in same group had similar structures and conserved motifs. All BnLACs contained hormone- and stress- related elements determined by cis-element analysis. The expression of BnLACs was relatively higher in the root, seed coat and stem than in other tissues. Furthermore, BnLAC4 and its predicted downstream genes showed earlier expression in the silique pericarps of short silique lines than long silique lines. Three miRNAs (miR397a, miR397b and miR6034) target 11 BnLACs were also predicted. The expression changes of BnLACs under series of stresses were further investigated by RNA sequencing (RNA-seq) and quantitative real-time polymerase chain reaction (qRT-PCR). The study will give a deeper understanding of the LAC gene family evolution and functions in B. napus.


Assuntos
Brassica napus/fisiologia , Lacase/genética , Estresse Fisiológico , Sequenciamento Completo do Genoma/métodos , Motivos de Aminoácidos , Brassica napus/enzimologia , Brassica napus/genética , Evolução Molecular , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Lacase/química , MicroRNAs/genética , Família Multigênica , Proteínas de Plantas/química , Proteínas de Plantas/genética , Conformação Proteica , RNA de Plantas/genética , Análise de Sequência de RNA
18.
Cell Mol Biol (Noisy-le-grand) ; 65(4): 29-36, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31078149

RESUMO

Concerns about nanoparticles environmental pollution risk have been increased globally due to an increase in the production of nanoparticles in recent years and their use in diverse cases. The purpose of this experiment was to study the alleviation effect of humic acid on nanoparticles toxicity in greenhouse conditions. Thus two separate experiments were conducted at the rosette growing stages of rapeseed in a factorial experiment as a completely randomized design with three replications. The first factor was copper and zinc oxide nanoparticle in five concentrations of 0, 500, 1000, 1500, 2000 mg.L-1 in each of experiments and the second factor was humic acid in two concentrations of 0 and 100 mg.L-1 in both experiments. The results showed that simultaneously application of humic acid and the nanoparticles resulted in increasing of chlorophyll, protein contents, and antioxidants enzymes activity. For example, the maximum activity of catalase was 170.72 and 296.82 µmol.min-1.mg-1 proteins when CuO nanoparticle was utilized alone and together with humic acid respectively. Also increasing the concentration of CuO nanoparticle reduced protein content from 2.44 to 1.88 (mg.gr-1 Fresh leaf weight), while its range was 2.86 and 2.49 (mg.gr-1 Fresh leaf weight) when adding the humic acid. Transmission electron microscopy images of root tissue confirm the decreasing of nanoparticles entrance to plant cell and tissue by humic acid. In general, application of humic acid alleviated the nanoparticles toxicity, due to the high adsorption capacity that is able to get out the metals from plants or like-hormonal activity probably.


Assuntos
Brassica napus/efeitos dos fármacos , Cobre/toxicidade , Substâncias Húmicas , Nanopartículas Metálicas/toxicidade , Óxido de Zinco/toxicidade , Antioxidantes/metabolismo , Brassica napus/enzimologia , Nanopartículas Metálicas/ultraestrutura , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/ultraestrutura , Prolina/metabolismo , Solo , Solubilidade
19.
Plant Cell Physiol ; 60(7): 1556-1566, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31073607

RESUMO

Oil crop Brassica napus is subjected to environmental stresses such as drought, cold and salt. Phospholipase Ds (PLDs) have vital roles in regulation of plant growth, development and stress tolerance. In this study, 32 BnaPLD genes were identified and classified into six subgroups depending on the conserved protein structures. High similarity in gene and protein structures exists between BnaPLDs and AtPLDs. Gene expression analysis showed that BnaPLDα1s and BnaPLDδs had higher expression than other PLDs. BnaPLDα1 and BnaPLDδ were significantly induced by abiotic stresses including dehydration, NaCl, abscisic acid (ABA) and 4�C. Lipidomic analysis showed that the content of main membrane phospholipids decreased gradually under stresses, except phosphatidylglycerol increased under the treatment of ABA and phosphatidylethanolamine increased under 4�C. Correspondingly, their product of phosphatidic acid increased often with a transient peak at 8 h. The plant height of mutants of PLDα1 was significantly reduced. Agronomic traits such as yield, seed number, silique number and branches were significantly impaired in PLDα1 mutants. These results indicate that there is a large family of PLD genes in B. napus, especially BnaPLDα1s and BnaPLDδs may play important roles in membrane lipids remodeling and maintaining of the growth and stress tolerance of B. napus.


Assuntos
Brassica napus/genética , Genes de Plantas/genética , Fosfolipase D/genética , Fosfolipídeos/metabolismo , Brassica napus/enzimologia , Brassica napus/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/fisiologia , Estudo de Associação Genômica Ampla , Metabolismo dos Lipídeos , Lipídeos/fisiologia , Fosfolipase D/metabolismo , Fosfolipídeos/fisiologia , Filogenia , Folhas de Planta/metabolismo , Estresse Fisiológico , Transcriptoma
20.
BMC Plant Biol ; 19(1): 124, 2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30940071

RESUMO

BACKGROUND: Acetolactate synthase (ALS)-inhibiting herbicide tribenuron-methyl (TBM) is an efficient gametocide that can cause rapeseed (Brassica napus L.) to become male sterile and outcrossing. To find the reason the TBM treatment leads to male sterility, an integrated study using cytological, physiological, and transcriptomic methods was conducted. RESULTS: Some temporary symptoms, including the discoloration of young leaves and a short halt of raceme elongation, were observed in the rapeseed plants exposed to TBM at an application rate of 1 µg per plant. Both chloroplasts in young leaves and plastids in anthers were deformed. TBM also reduced the leaf photosynthetic rate and the contents of chlorophyll, soluble sugar and pyruvate. Both the tapetal cells and uni-nucleate microspores in the treated plants showed large autophagic vacuoles, and the tissue degenerated quickly. A transcriptomic comparison with the control identified 200 upregulated and 163 downregulated differential expression genes in the small flower buds of the TBM treatment. The genes encoding functionally important proteins, including glucan endo-1,3-beta-glucosidase A6, QUARTET3 (QRT3), ARABIDOPSIS ANTHER 7 (ATA7), non-specific lipid-transfer protein LTP11 and LTP12, histone-lysine N-methyltransferase ATXR6, spermidine coumaroyl-CoA acyltransferase (SCT), and photosystem II reaction centre protein psbB, were downregulated by TBM exposure. Some important genes encoding autophagy-related protein ATG8a and metabolic detoxification related proteins, including DTX1, DTX6, DTX35, cytosolic sulfotransferase SOT12, and six members of glutathione S-transferase, were upregulated. In addition, several genes related to hormone stimulus, such as 1-aminocyclopropane-1-carboxylate synthase 8 (ACS8), ethylene-responsive factor ERF1A, ERF1, ERF71, CRF6, and RAP2-3, were also upregulated. The transcriptional regulation is in accordance with the functional abnormalities of pollen wall formation, lipid metabolism, chloroplast structure, ethylene generation, cell cycle, and tissue autophagy. CONCLUSION: The results suggested that except for ALS, the metabolic pathways related to lipid metabolism, pollen exine formation, photosynthesis and hormone response are associated with male sterility induced by TBM. The results provide new insight into the molecular mechanisms of inducing male sterility by sulfonylurea.


Assuntos
Acetolactato Sintase/antagonistas & inibidores , Sulfonatos de Arila/farmacologia , Brassica napus/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Herbicidas/farmacologia , Infertilidade das Plantas/efeitos dos fármacos , Acetolactato Sintase/metabolismo , Brassica napus/enzimologia , Brassica napus/fisiologia , Regulação para Baixo/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/fisiologia , Proteínas de Plantas/antagonistas & inibidores , Proteínas de Plantas/metabolismo
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