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1.
BMC Plant Biol ; 19(1): 336, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370790

RESUMO

BACKGROUND: APETALA2-like genes encode plant-specific transcription factors, some of which possess one microRNA172 (miR172) binding site. The miR172 and its target euAP2 genes are involved in the process of phase transformation and flower organ development in many plants. However, the roles of miR172 and its target AP2 genes remain largely unknown in Brassica napus (B. napus). RESULTS: In this study, 19 euAP2 and four miR172 genes were identified in the B. napus genome. A sequence analysis suggested that 17 euAP2 genes were targeted by Bna-miR172 in the 3' coding region. EuAP2s were classified into five major groups in B.napus. This classification was consistent with the exon-intron structure and motif organization. An analysis of the nonsynonymous and synonymous substitution rates revealed that the euAP2 genes had gone through purifying selection. Whole genome duplication (WGD) or segmental duplication events played a major role in the expansion of the euAP2 gene family. A cis-regulatory element (CRE) analysis suggested that the euAP2s were involved in the response to light, hormones, stress, and developmental processes including circadian control, endosperm and meristem expression. Expression analysis of the miR172-targeted euAP2s in nine different tissues showed diverse spatiotemporal expression patterns. Most euAP2 genes were highly expressed in the floral organs, suggesting their specific functions in flower development. BnaAP2-1, BnaAP2-5 and BnaTOE1-2 had higher expression levels in late-flowering material than early-flowering material based on RNA-seq and qRT-PCR, indicating that they may act as floral suppressors. CONCLUSIONS: Overall, analyses of the evolution, structure, tissue specificity and expression of the euAP2 genes were peformed in B.napus. Based on the RNA-seq and experimental data, euAP2 may be involved in flower development. Three euAP2 genes (BnaAP2-1, BnaAP2-5 and BnaTOE1-2) might be regarded as floral suppressors. The results of this study provide insights for further functional characterization of the miR172 /euAP2 module in B.napus.


Assuntos
Brassica napus/genética , Flores/crescimento & desenvolvimento , Genes de Plantas/genética , MicroRNAs/genética , Brassica napus/crescimento & desenvolvimento , Mapeamento Cromossômico , Sequência Conservada/genética , Genes de Plantas/fisiologia , Estudo de Associação Genômica Ampla , MicroRNAs/fisiologia , Filogenia , Alinhamento de Sequência
2.
BMC Plant Biol ; 19(1): 372, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31438864

RESUMO

BACKGROUND: Correct timing of flowering is critical for plants to produce enough viable offspring. In Arabidopsis thaliana (Arabidopsis), flowering time is regulated by an intricate network of molecular signaling pathways. Arabidopsis srr1-1 mutants lacking SENSITIVITY TO RED LIGHT REDUCED 1 (SRR1) expression flower early, particularly under short day (SD) conditions (1). SRR1 ensures that plants do not flower prematurely in such non-inductive conditions by controlling repression of the key florigen FT. Here, we have examined the role of SRR1 in the closely related crop species Brassica napus. RESULTS: Arabidopsis SRR1 has five homologs in Brassica napus. They can be divided into two groups, where the A02 and C02 copies show high similarity to AtSRR1 on the protein level. The other group, including the A03, A10 and C09 copies all carry a larger deletion in the amino acid sequence. Three of the homologs are expressed at detectable levels: A02, C02 and C09. Notably, the gene copies show a differential expression pattern between spring and winter type accessions of B. napus. When the three expressed gene copies were introduced into the srr1-1 background, only A02 and C02 were able to complement the srr1-1 early flowering phenotype, while C09 could not. Transcriptional analysis of known SRR1 targets in Bna.SRR1-transformed lines showed that CYCLING DOF FACTOR 1 (CDF1) expression is key for flowering time control via SRR1. CONCLUSIONS: We observed subfunctionalization of the B. napus SRR1 gene copies, with differential expression between early and late flowering accessions of some Bna.SRR1 copies. This suggests involvement of Bna.SRR1 in regulation of seasonal flowering in B. napus. The C09 gene copy was unable to complement srr1-1 plants, but is highly expressed in B. napus, suggesting specialization of a particular function. Furthermore, the C09 protein carries a deletion which may pinpoint a key region of the SRR1 protein potentially important for its molecular function. This is important evidence of functional domain annotation in the highly conserved but unique SRR1 amino acid sequence.


Assuntos
Brassica napus/genética , Flores/genética , Genes de Plantas , Proteínas de Plantas/genética , Flores/crescimento & desenvolvimento , Dosagem de Genes , Expressão Gênica , Filogenia , Proteínas de Plantas/fisiologia
3.
BMC Plant Biol ; 19(1): 294, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31272381

RESUMO

BACKGROUND: Rapeseed is the third largest oil seed crop in the world. The seeds of this plant store lipids in oil bodies, and oleosin is the most important structural protein in oil bodies. However, the function of oleosin in oil crops has received little attention. RESULTS: In the present study, 48 oleosin sequences from the Brassica napus genome were identified and divided into four lineages (T, U, SH, SL). Synteny analysis revealed that most of the oleosin genes were conserved, and all of these genes experienced purifying selection during evolution. Three and four important oleosin genes from Arabidopsis and B. napus, respectively, were cloned and analyzed for function in Arabidopsis. Overexpression of these oleosin genes in Arabidopsis increased the seed oil content slightly, except for BnaOLE3. Further analysis revealed that the average oil body size of the transgenic seeds was slightly larger than that of the wild type (WT), except for BnaOLE1. The fatty acid profiles showed that the linoleic acid content (13.3% at most) increased and the peanut acid content (11% at most) decreased in the transgenic lines. In addition, the seed size and thousand-seed weight (TSW) also increased in the transgenic lines, which could lead to increased total lipid production. CONCLUSION: We identified oleosin genes in the B. napus genome, and overexpression of oleosin in Arabidopsis seeds increased the seed weight and linoleic acid content (13.3% at most).


Assuntos
Brassica napus/genética , Estudo de Associação Genômica Ampla , Proteínas de Plantas/genética , Brassica napus/metabolismo , Genes de Plantas , Filogenia , Óleos Vegetais/metabolismo , Proteínas de Plantas/metabolismo , Sintenia
4.
BMC Plant Biol ; 19(1): 324, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31324149

RESUMO

BACKGROUND: Leaf shape development research is important because leaf shapes such as moderate curling can help to improve light energy utilization efficiency. Leaf growth and development includes initiation of the leaf primordia and polar differentiation of the proximal-distal, adaxial-abaxial, and centrolateral axes. Changes in leaf adaxial-abaxial polarity formation, auxin synthesis and signaling pathways, and development of sclerenchyma and cuticle can cause abnormal leaf shapes such as up-curling leaf. Although many genes related to leaf shape development have been reported, the detailed mechanism of leaf development is still unclear. Here, we report an up-curling leaf mutant plant from our Brassica napus germplasm. We studied its inheritance, mapped the up-curling leaf locus BnUC1, built near-isogenic lines for the Bnuc1 mutant, and evaluated the effect of the dominant leaf curl locus on leaf photosynthetic efficiency and agronomic traits. RESULTS: The up-curling trait was controlled by one dominant locus in a progeny population derived from NJAU5734 and Zhongshuang 11 (ZS11). This BnUC1 locus was mapped in an interval of 2732.549 kb on the A05 chromosome of B. napus using Illumina Brassica 60 K Bead Chip Array. To fine map BnUC1, we designed 201 simple sequence repeat (SSR) primers covering the mapping interval. Among them, 16 polymorphic primers that narrowed the mapping interval to 54.8 kb were detected using a BC6F2 family population with 654 individuals. We found six annotated genes in the mapping interval using the B. napus reference genome, including BnaA05g18250D and BnaA05g18290D, which bioinformatics and gene expression analyses predicted may be responsible for leaf up-curling. The up-curling leaf trait had negative effects on the agronomic traits of 30 randomly selected individuals from the BC6F2 population. The near-isogenic line of the up-curling leaf (ZS11-UC1) was constructed to evaluate the effect of BnUC1 on photosynthetic efficiency. The results indicated that the up-curling leaf trait locus was beneficial to improve the photosynthetic efficiency. CONCLUSIONS: An up-curling leaf mutant Bnuc1 was controlled by one dominant locus BnUC1. This locus had positive effects on photosynthetic efficiency, negative effects on some agronomic traits, and may help to increase planting density in B. napus.


Assuntos
Brassica napus/genética , Genes de Plantas/genética , Folhas de Planta/anatomia & histologia , Brassica napus/anatomia & histologia , Clorofila/metabolismo , Mapeamento Cromossômico , Genes de Plantas/fisiologia , Loci Gênicos , Mutação , Fotossíntese , Reação em Cadeia da Polimerase em Tempo Real
5.
Int J Mol Sci ; 20(11)2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31195741

RESUMO

Winter rapeseed is not only an important oilseed crop, but also a winter cover crop in Northern China, where its production was severely limited by freezing stress. As an overwinter crop, the production is severely limited by freezing stress. Therefore, understanding the physiological and molecular mechanism of winter rapeseed (Brassica napus L.) in freezing stress responses becomes essential for the improvement and development of freezing-tolerant varieties of Brassica napus. In this study, morphological, physiological, ultrastructure and transcriptome changes in the Brassica napus line "2016TS(G)10" (freezing-tolerance line) that was exposed to -2 °C for 0 h, 1 h, 3 h and 24 h were characterized. The results showed that freezing stress caused seedling dehydration, and chloroplast dilation and degradation. The content of malondialdehyde (MDA), proline, soluble protein and soluble sugars were increased, as well as the relative electrolyte leakage (REL) which was significantly increased at frozen 24 h. Subsequently, RNA-seq analysis revealed a total of 98,672 UniGenes that were annotated in Brassica napus and 3905 UniGenes were identified as differentially expressed genes after being exposed to freezing stress. Among these genes, 2312 (59.21%) were up-regulated and 1593 (40.79%) were down-regulated. Most of these DEGs were significantly annotated in the carbohydrates and energy metabolism, signal transduction, amino acid metabolism and translation. Most of the up-regulated DEGs were especially enriched in plant hormone signal transduction, starch and sucrose metabolism pathways. Transcription factor enrichment analysis showed that the AP2/ERF, WRKY and MYB families were also significantly changed. Furthermore, 20 DEGs were selected to validate the transcriptome profiles via quantitative real-time PCR (qRT-PCR). In conclusion, the results provide an overall view of the dynamic changes in physiology and insights into the molecular regulation mechanisms of winter Brassica napus in response to freezing treatment, expanding our understanding on the complex molecular mechanism in plant response to freezing stress.


Assuntos
Brassica napus/genética , Brassica napus/fisiologia , Congelamento , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico/genética , Brassica napus/ultraestrutura , Ontologia Genética , Anotação de Sequência Molecular , Folhas de Planta/ultraestrutura
6.
BMC Plant Biol ; 19(1): 264, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-31215396

RESUMO

BACKGROUND: Brassica napus L. has little or no primary dormancy, but exhibits great variation in secondary dormancy. Secondary dormancy potential in oilseed rape can lead to the emergence of volunteer plants that cause genetic contamination, reduced quality and biosafety issues. However, the mechanisms underlying secondary dormancy are poorly understood. In this study, cultivars Huaiyou-WSD-H2 (H) and Huaiyou-SSD-V1 (V), which exhibit low (approximately 5%) and high (approximately 95%) secondary dormancy rate, respectively, were identified. Four samples, before (Hb and Vb) and after (Ha and Va) secondary dormancy induction by polyethylene glycol (PEG), were collected to identify the candidate genes involved in secondary dormancy via comparative transcriptome profile analysis. RESULTS: A total of 998 differentially expressed genes (DEGs), which are mainly involved in secondary metabolism, transcriptional regulation, protein modification and signaling pathways, were then detected. Among these DEGs, the expression levels of those involved in the sulfur-rich indole glucosinolate (GLS)-linked auxin biosynthesis pathway were markedly upregulated in the dormant seeds (Va), which were validated by qRT-PCR and subsequently confirmed via detection of altered concentrations of indole-3-acetic acid (IAA), IAA conjugates and precursors. Furthermore, exogenous IAA applications to cultivar H enhanced secondary dormancy. CONCLUSION: This study first (to our knowledge) elucidated that indole GLS-linked auxin biosynthesis is enhanced during secondary dormancy induced by PEG, which provides valuable information concerning secondary dormancy and expands the current understanding of the role of auxin in rapeseed.


Assuntos
Brassica napus/metabolismo , Ácidos Indolacéticos/metabolismo , Dormência de Plantas , Reguladores de Crescimento de Planta/metabolismo , Brassica napus/genética , Brassica napus/fisiologia , Perfilação da Expressão Gênica , Genes de Plantas/genética , Genes de Plantas/fisiologia , Glucosinolatos/metabolismo , Indóis/metabolismo , Redes e Vias Metabólicas , Dormência de Plantas/genética , Dormência de Plantas/fisiologia , Metabolismo Secundário/genética , Metabolismo Secundário/fisiologia
7.
BMC Plant Biol ; 19(1): 280, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31242871

RESUMO

BACKGROUND: The xylem sap of vascular plants primarily transports water and mineral nutrients from the roots to the shoots and also transports heavy metals such as cadmium (Cd). Proteomic changes in xylem sap is an important mechanism for detoxifying Cd by plants. However, it is unclear how proteins in xylem sap respond to Cd. Here, we investigated the effects of Cd stress on the xylem sap proteome of Brassica napus using a label-free shotgun proteomic approach to elucidate plant response mechanisms to Cd toxicity. RESULTS: We identified and quantified 672 proteins; 67% were predicted to be secretory, and 11% (73 proteins) were unique to Cd-treated samples. Cd stress caused statistically significant and biologically relevant abundance changes in 28 xylem sap proteins. Among these proteins, the metabolic pathways that were most affected were related to cell wall modifications, stress/oxidoreductases, and lipid and protein metabolism. We functionally validated a plant defensin-like protein, BnPDFL, which belongs to the stress/oxidoreductase category, that was unique to the Cd-treated samples and played a positive role in Cd tolerance. Subcellular localization analysis revealed that BnPDFL is cell wall-localized. In vitro Cd-binding assays revealed that BnPDFL has Cd-chelating activity. BnPDFL heterologous overexpression significantly enhanced Cd tolerance in E. coli and Arabidopsis. Functional disruption of Arabidopsis plant defensin genes AtPDF2.3 and AtPDF2.2, which are mainly expressed in root vascular bundles, significantly decreased Cd tolerance. CONCLUSIONS: Several xylem sap proteins in Brassica napus are differentially induced in response to Cd treatment, and plant defensin plays a positive role in Cd tolerance.


Assuntos
Brassica napus/genética , Cádmio/efeitos adversos , Proteoma/efeitos dos fármacos , Poluentes do Solo/efeitos adversos , Xilema/fisiologia , Brassica napus/efeitos dos fármacos , Brassica napus/metabolismo , Proteoma/genética , Proteoma/metabolismo , Xilema/efeitos dos fármacos
8.
Nat Commun ; 10(1): 2878, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253789

RESUMO

Brassica napus, an allotetraploid crop, is hypothesized to be a hybrid from unknown varieties of Brassica rapa and Brassica oleracea. Despite the economic importance of B. napus, much is unresolved regarding its phylogenomic relationships, genetic structure, and diversification. Here we conduct a comprehensive study among diverse accessions from 183 B. napus (including rapeseed, rutabaga, and Siberian kale), 112 B. rapa, and 62 B. oleracea and its wild relatives. Using RNA-seq of B. napus accessions, we define the genetic diversity and sub-genome variance of six genetic clusters. Nuclear and organellar phylogenies for B. napus and its progenitors reveal varying patterns of inheritance and post-formation introgression. We discern regions with signatures of selective sweeps and detect 8,187 differentially expressed genes with implications for B. napus diversification. This study highlights the complex origin and evolution of B. napus providing insights that can further facilitate B. napus breeding and germplasm preservation.


Assuntos
Brassica napus/genética , Brassica napus/metabolismo , Ploidias , Regulação da Expressão Gênica de Plantas , Genômica , Organelas , Filogenia , Folhas de Planta/crescimento & desenvolvimento , Tubérculos , Polimorfismo de Nucleotídeo Único , RNA de Plantas/genética , Análise de Sequência de RNA , Transcriptoma
9.
J Agric Food Chem ; 67(24): 6736-6747, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31184154

RESUMO

Nitrogen is essential for plant growth and crop productivity; however, nitrogen use efficiency (NUE) decreases with increasing N supply, resulting in a waste of resources. Molecular mechanisms underlying low-nitrogen (LN)-mediated enhancement of NUE are not clear. We used high-NUE Brassica napus genotype H (Xiangyou 15), low-NUE B. napus genotype L (814), and Arabidopsis mutant aux1 to elucidate the mechanism underlying the changes in NUE under different rates of N fertilizer application. NUE of B. napus increased under LN, which enhanced N uptake ability by regulating root system architecture and plasma membrane H+-ATPase activity; AUX1 was involved in this process. Additionally, BnNRT1.5 was upregulated and BnNRT1.8 was downregulated under LN, whereby more N was transferred to the shoot through enhanced N transport. Observed changes in photosynthesis under LN were associated with N assimilation efficiency. Our study provides new insights into the mechanisms of plant adaptation to the environment.


Assuntos
Arabidopsis/metabolismo , Brassica napus/metabolismo , Nitratos/metabolismo , Nitrogênio/metabolismo , Arabidopsis/genética , Transporte Biológico , Brassica napus/genética , Fertilizantes/análise , Regulação da Expressão Gênica de Plantas , Nitrogênio/análise , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo
10.
BMC Plant Biol ; 19(1): 203, 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-31096923

RESUMO

BACKGROUND: Brassica napus is of substantial economic value for vegetable oil, biofuel, and animal fodder production. The breeding of yellow-seeded B. napus to improve seed quality with higher oil content, improved oil and meal quality with fewer antinutrients merits attention. Screening the genes related to this phenotype is valuable for future rapeseed breeding. RESULTS: A total of 85,407 genes, including 4317 novel genes, were identified in the developing seeds of yellow- and black-seeded B. napus, and yellow rapeseed was shown to be an introgression line between black-seeded B. napus and yellow-seeded Sinapis alba. A total of 15,251 differentially expressed genes (DEGs) were identified among all the libraries, and 563 and 397 common DEGs were identified throughout black and yellow seed development, including 80 upregulated and 151 downregulated genes related to seed development and fatty acid accumulation. In addition, 11 up-DEGs and 31 down-DEGs were identified in all developmental stages of yellow rapeseed compared with black seed. Enrichment analysis revealed that many DEGs were involved in biosynthetic processes, pigment metabolism, and oxidation-reduction processes, such as flavonoid and phenylpropanoid biosynthesis, phenylalanine metabolism, flavone and flavonol biosynthesis, and fatty acid biosynthesis and metabolism. We found that more than 77 DEGs were related to flavonoid and lignin biosynthesis, including 4CL, C4H, and PAL, which participated in phenylalanine metabolism, and BAN, CHI/TT5, DFR, F3H, FLS, LDOX, PAP, CHS/TT4, TT5, bHLH/TT8, WD40, MYB, TCP, and CYP, which were involved in flavonoid biosynthesis. Most of these DEGs were downregulated in yellow rapeseed and were consistent with the decreased flavonoid and lignin contents. Both up- and down-DEGs related to fatty acid biosynthesis and metabolism were also analyzed, which could help to explain the improved oil content of yellow rapeseed. CONCLUSION: This research provided comprehensive transcriptome data for yellow-seeded B. napus with a unique genetic background, and all the DEGs in comparison with the black-seeded counterpart could help to explain seed quality differences, such as lower pigmentation and lignin contents, and higher oil content.


Assuntos
Brassica napus/genética , Sementes/genética , Brassica napus/crescimento & desenvolvimento , Ácidos Graxos/metabolismo , Flavonoides/metabolismo , Perfilação da Expressão Gênica , Genes de Plantas/genética , Genes de Plantas/fisiologia , Lignina/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Sementes/crescimento & desenvolvimento , Análise de Sequência de DNA , Transcriptoma
11.
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
12.
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
13.
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
14.
Mol Plant Microbe Interact ; 32(10): 1360-1377, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31090490

RESUMO

Clubroot disease, caused by Plasmodiophora brassicae Woronin, is a major threat to the production of Brassica' crops. Resistance to different P. brassicae pathotypes has been reported in the A genome, chromosome A08; however, the molecular mechanism of this resistance, especially the involvement of long noncoding RNAs (lncRNAs), is not understood. We have used a strand-specific lncRNA-Seq approach to catalog lncRNAs from the roots of clubroot-susceptible and -resistant Brassica napus lines. In total, 530 differentially expressed (DE) lncRNAs were identified, including 88% of long intergenic RNAs and 11% natural antisense transcripts. Sixteen lncRNAs were identified as target mimics of the microRNAs (miRNAs) and eight were identified as the precursors of miRNAs. KEGG pathway analysis of the DE lncRNAs showed that the cis-regulated target genes mostly belong to the phenylpropanoid biosynthetic pathway (15%) and plant-pathogen interactions (15%) while the transregulated target genes mostly belong to carbon (18%) and amino acid biosynthesis pathway (19%). In all, 24 DE lncRNAs were identified from chromosome A08, which is known to harbor a quantitative trait locus conferring resistance to different P. brassicae pathotypes; however, eight of these lncRNAs showed expression only in the resistant plants. These results could form the basis for future studies aimed at delineating the roles of lncRNAs in plant-microbe interactions.


Assuntos
Brassica napus , Resistência à Doença , Plasmodioforídeos , RNA Longo não Codificante , Brassica napus/classificação , Brassica napus/genética , Brassica napus/parasitologia , Resistência à Doença/genética , Plasmodioforídeos/fisiologia , RNA Longo não Codificante/genética
15.
Plant Sci ; 283: 157-164, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128685

RESUMO

Combining ability is crucial for parent selection in crop hybrid breeding. Many studies have attempted to provide reliable and quick methods to identify genome regions in parental lines correlating with improved hybrid performance. The local haplotype patterns surrounding densely spaced DNA markers include a large amount of genetic information, and analysis of the relationships between haplotypes and hybrid performance can provide insight into the underlying genome regions which might contribute to enhancing combining ability. Here, we generated 24,403 single-copy, genome-wide SNP loci and calculated the general combining ability (GCA) of 950 hybrids from a diverse panel of 475 pollinators of spring-type canola inbred lines crossed with two testers for days to flowering (DTF) and seed glucosinolate content (GSL). We performed a genome-wide analysis of the haplotypes and detected eight and seven haplotype regions that were significantly associated with the GCA values for DTF and seed GSL, respectively. Additionally, two haplotype blocks containing orthologs of flowering time genes FLOWERING LOCUS T (FT) and FLOWERING LOCUS C (FLC) on chromosome A02 showed additive epistatic interactions influencing flowering time. Moreover, two homoeologous haplotype regions on chromosomes A02 and C02 corresponded to major quantitative trait loci (QTL) for GSL which showed additive effects related to reduction of seed GSL in F1 hybrids. Our study showed that haplotype analysis has the potential to substantially improve the efficiency of hybrid breeding programs.


Assuntos
Brassica napus/genética , Característica Quantitativa Herdável , Brassica napus/crescimento & desenvolvimento , Mapeamento Cromossômico , Flores/crescimento & desenvolvimento , Genes de Plantas/genética , Estudos de Associação Genética , Estudo de Associação Genômica Ampla , Haplótipos/genética , Vigor Híbrido/genética , Desequilíbrio de Ligação/genética , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único/genética
16.
Nat Commun ; 10(1): 2354, 2019 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142748

RESUMO

In allopolyploids, correct chromosome segregation requires suppression of non-homologous crossovers while levels of homologous crossovers are ensured. To date, no mechanism able to specifically inhibit non-homologous crossovers has been described in allopolyploids other than in bread wheat. Here, we show that reducing the number of functional copies of MSH4, an essential gene for the main crossover pathway, prevents non-homologous crossovers in allotetraploid Brassica napus. We show that non-homologous crossovers originate almost exclusively from the MSH4-dependent recombination pathway and that their numbers decrease when MSH4 returns to single copy in B. napus; by contrast, homologous crossovers remain unaffected by MSH4 duplicate loss. We also demonstrate that MSH4 systematically returns to single copy following numerous independent polyploidy events, a pattern that is probably not by chance. These results suggest that stabilization of allopolyploid meiosis can be enhanced by loss of a key meiotic recombination gene.


Assuntos
Brassica napus/genética , Segregação de Cromossomos/genética , Troca Genética/genética , Meiose/genética , Proteínas MutS/genética , Poliploidia , Cromossomos de Plantas/metabolismo , Variações do Número de Cópias de DNA , Recombinação Homóloga
17.
BMC Plant Biol ; 19(1): 156, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31023216

RESUMO

BACKGROUND: Seed germination and seedling establishment are two of the most critical phases in plant development. However, the molecular mechanisms underlying the effect of phosphorus on seed germination and post-germinated growth of oilseed rape are unclear so far. Here, we report the role of BnPHT1;4 in seed germination and early seedling development of Brassica napus. RESULTS: Our results show that BnPHT1;4 is preferentially expressed in cotyledons of early developing seedlings. Overexpression of BnPHT1;4 in oilseed rape promoted seed germination and seedling growth. Expression levels of the genes related to ABA and GA biosynthesis and signaling were significantly altered in BnPHT1;4 transgenic seedlings. Consequently, active GA level was up-regulated, whereas ABA content was down-regulated in BnPHT1;4 transgenic seedlings. Furthermore, exogenous GA could promote seed germination of wild type, while exogenous ABA could partially recover the advanced-germination phenotype of BnPHT1;4 transgenic seeds. Total phosphorus content in cotyledons of the transgenic seedlings was decreased more rapidly than that in wild type when Pi was supplied or deficient, and Pi contents in shoots and roots of the BnPHT1;4 transgenic plants were higher than those in wild type under high and low Pi conditions. CONCLUSIONS: Our data suggest that the high-affinity transporter BnPHT1;4 is involved in phosphorus acquisition and mobilization for facilitating seed germination and seedling growth of Brassica napus by modulating ABA and GA biosynthesis.


Assuntos
Brassica napus/metabolismo , Germinação , Proteínas de Membrana Transportadoras/metabolismo , Fósforo/metabolismo , Proteínas de Plantas/metabolismo , Plântula/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Ácido Abscísico/biossíntese , Brassica napus/genética , Cotilédone/metabolismo , Regulação da Expressão Gênica de Plantas , Giberelinas/biossíntese , Proteínas de Membrana Transportadoras/genética , Fenótipo , Fósforo/deficiência , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Plântula/metabolismo , Sementes/metabolismo , Solo
18.
BMC Genomics ; 20(1): 304, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-31014236

RESUMO

BACKGROUND: Although rapeseed (Brassica napus L.) mutant forming multiple siliques was morphologically described and considered to increase the silique number per plant, an important agronomic trait in this crop, the molecular mechanism underlying this beneficial trait remains unclear. Here, we combined bulked-segregant analysis (BSA) and whole genome re-sequencing (WGR) to map the genomic regions responsible for the multi-silique trait using two pools of DNA from the near-isogenic lines (NILs) zws-ms (multi-silique) and zws-217 (single-silique). We used the Euclidean Distance (ED) to identify genomic regions associated with this trait based on both SNPs and InDels. We also conducted transcriptome sequencing to identify differentially expressed genes (DEGs) between zws-ms and zws-217. RESULTS: Genetic analysis using the ED algorithm identified three SNP- and two InDel-associated regions for the multi-silique trait. Two highly overlapped parts of the SNP- and InDel-associated regions were identified as important intersecting regions, which are located on chromosomes A09 and C08, respectively, including 2044 genes in 10.20-MB length totally. Transcriptome sequencing revealed 129 DEGs between zws-ms and zws-217 in buds, including 39 DEGs located in the two abovementioned associated regions. We identified candidate genes involved in multi-silique formation in rapeseed based on the results of functional annotation. CONCLUSIONS: This study identified the genomic regions and candidate genes related to the multi-silique trait in rapeseed.


Assuntos
Brassica napus/genética , Genômica , Locos de Características Quantitativas/genética , Perfilação da Expressão Gênica , Mutação INDEL , Anotação de Sequência Molecular , Polimorfismo de Nucleotídeo Único , Homologia de Sequência do Ácido Nucleico
19.
Theor Appl Genet ; 132(7): 2111-2123, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30980103

RESUMO

The INDEHISCENT (IND) and ALCATRAZ (ALC) gene homologues have been reported to be essential for dehiscence of fruits in Brassica species. But their functions for pod shatter resistance in Brassica napus, an important oil crops, are not well understood. Here, we assessed the functions of these two genes in rapeseed using CRISPR/Cas9 technology. The induced mutations were stably transmitted to successive generations, and a variety of homozygous mutants with loss-of-function alleles of the target genes were obtained for phenotyping. The results showed that the function of BnIND gene is essential for pod shatter and highly conserved in Brassica species, whereas the BnALC gene appears to have limited potential for rapeseed shatter resistance. The homoeologous copies of the BnIND gene have partially redundant roles in rapeseed pod shatter, with BnA03.IND exhibiting higher contributions than BnC03.IND. Analysis of data obtained from the gene expression and sequence variations of gene copies revealed that cis-regulatory divergences alter gene expression and underlie the functional differentiation of BnIND homologues. Collectively, our results generate valuable resources for rapeseed breeding programs, and more importantly provide a strategy to improve polyploid crops.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Brassica napus/genética , Sistemas CRISPR-Cas , Proteínas de Plantas/genética , Sementes/fisiologia , Alelos , Edição de Genes , Técnicas de Inativação de Genes , Genes de Plantas , Fenótipo , Plantas Geneticamente Modificadas
20.
BMC Genomics ; 20(1): 317, 2019 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31023229

RESUMO

BACKGROUND: WUSCHEL-related homeobox (WOX) genes encoding plant-specific homeobox (HB) transcription factors play important roles in the growth and development of plants. To date, WOX genes has been identified and analyzed in many polyploids (such as cotton and tobacco), but the evolutionary analysis of them during polyploidization is rare. With the completion of genome sequencing, allotetraploid Brassica napus and its diploid progenitors (B. rapa and B. oleracea) are a good system for studying this question. RESULTS: In this study, 52, 25 and 29 WOX genes were identified in allotetraploid B. napus (2n = 4x = 38, AnCn), the An genome donor B. rapa (2n = 2x = 20, Ar) and the Cn genome donor B. oleracea (2n = 2x = 18, Co), respectively. All identified WOX genes in B. napus and its diploid progenitors were divided into three clades, and these genes were selected to perform gene structure and chromosome location analysis. The results showed that at least 70 and 67% of WOX genes maintained the same gene structure and relative position on chromosomes, respectively, indicating that WOX genes in B. napus were highly conserved at the DNA level during polyploidization. In addition, the analysis of duplicated genes and transposable elements (TEs) near WOX genes showed that whole-genome triplication (WGT) events, segmental duplication and abundant TEs played important roles in the expansion of the WOX gene family in B. napus. Moreover, the analysis of the expression profiles of WOX gene pairs with evolutionary relationships suggested that the WOX gene family may have changed at the transcriptional regulation level during polyploidization. CONCLUSIONS: The results of this study increased our understanding of the WOX genes in B. napus and its diploid progenitors, providing a rich resource for further study of WOX genes in these species. In addition, the changes in WOX genes during the process of polyploidization were discussed from the aspects of gene number, gene structure, gene relative location and gene expression, which provides a reference for future polyploidization analysis.


Assuntos
Brassica napus/genética , Genoma de Planta , Proteínas de Homeodomínio/genética , Mapeamento Cromossômico , Elementos de DNA Transponíveis/genética , Diploide , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/classificação , Família Multigênica , Filogenia , Poliploidia
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