RESUMO
Cytochromes P450 monooxygenases (CYP450s) constitute the largest enzymic protein family that is widely present in plants, animals, and microorganisms, participate in numerous metabolic pathways, and play diverse roles in development, metabolism, and defense. Rapeseed (Brassica napus) is an important oil crop worldwide and have many versions of reference genome. However, there is no systemically comparative genome-wide analysis of CYP450 family genes in rapeseed and its parental species B. rapa and B. oleracea. In this study, we identified 765, 293 and 437 CYP450 genes in B. napus, B. rapa and B. oleracea, respectively, which were unevenly located in A01-A10 and/or C01-C09 chromosomes in corresponding species. Phylogenetic relationship analysis indicated that 1745 CYP450 proteins from three Brassica species and Arabidopsis were divided into 4 groups. Whole genome duplication (WGD) or segmental duplication resulted in gene expansion of CYP450 family in three Brassica species. There were 33-83 SSR loci in CYP450 genes of three Brassica species, and numerous transcription factor binding sites were identified in their promoters. A total of 459-777 miRNAs were predicted to target 174-426 CYP450 genes in three Brassica species. Based on transcriptome data, BnCYP450s, BrCYP450s and BoCYP450s were differentially expressed in various tissues. There existed numerous BnCYP450 DEGs in response to pathogens and abiotic stresses. Besides, many BnCYP450 DEGs were involved in the regulation of important traits, such as seed germination, seed ALA content, and yellow-seed. The qRT-PCR experiment confirmed the transcriptome analysis results by validating two representative Sclerotinia-responsive BnCYP450 DEGs as an example. Three BnCYP450s genes (CYP707A1, CYP81F1, CYP81H1) might be regulated by seed-specific transcription factors BnTT1 and BnbZIP67 to participate in the development and metabolism of seed coat and embryo by undertaking related metabolic reactions.
RESUMO
The main planting areas for pepper (Capsicum sp.) are high in cadmium (Cd), which is the most prevalent heavy metal pollutant worldwide. Breeding pepper cultivars with low Cd levels can promote sustainable agricultural production and ensure the safety of pepper products. To identify breeding targets for reducing Cd accumulation in pepper fruits, we performed a genome-wide association study on 186 accessions. Polymorphisms were associated with fruit Cd content in a genomic region containing a homolog of Arabidopsis (Arabidopsis thaliana) Heavy metal-transporting ATPase 1 (HMA1) encoding a P-type ATPase. In two cultivars with contrasting Cd accumulation, transcriptome analysis revealed differentially expressed genes enriched for carbohydrate metabolism and photosynthesis in fruits with high Cd accumulation, and a Cd2+/Zn2+-exporting ATPase gene (HMA). Heterologous expression of CaHMA1 in yeast increases Cd sensitivity. Overexpression of CaHMA1 conferred a severe increase in Cd content in Arabidopsis plants, whereas reduced CaHMA1 expression in pepper fruits decreased Cd content. We propose that CaHMA1 expression may be an important component of the high Cd accumulation in pepper plants.
Assuntos
Arabidopsis , Frutas , Frutas/genética , Cádmio , Arabidopsis/genética , Estudo de Associação Genômica Ampla , Adenosina TrifosfatasesRESUMO
Yellow-seed trait is a desirable breeding characteristic of rapeseed (Brassica napus) that could greatly improve seed oil yield and quality. However, the underlying mechanisms controlling this phenotype in B. napus plants are difficult to discern because of their complexity. Here, we assemble high-quality genomes of yellow-seeded (GH06) and black-seeded (ZY821). Combining in-depth fine mapping of a quantitative trait locus (QTL) for seed color with other omics data reveal BnA09MYB47a, encoding an R2R3-MYB-type transcription factor, as the causal gene of a major QTL controlling the yellow-seed trait. Functional studies show that sequence variation of BnA09MYB47a underlies the functional divergence between the yellow- and black-seeded B. napus. The black-seed allele BnA09MYB47aZY821, but not the yellow-seed allele BnA09MYB47aGH06, promotes flavonoid biosynthesis by directly activating the expression of BnTT18. Our discovery suggests a possible approach to breeding B. napus for improved commercial value and facilitates flavonoid biosynthesis studies in Brassica crops.
Assuntos
Brassica napus , Brassica napus/genética , Melhoramento Vegetal , Sementes/genética , Fenótipo , Genômica , FlavonoidesRESUMO
Modern people generally suffer from α-linolenic acid (ALA) deficiency, since most staple food oils are low in ALA content. Thus, the enhancement of ALA in staple oil crops is of importance. In this study, the FAD2 and FAD3 coding regions from the ALA-king species Perilla frutescens were fused using a newly designed double linker LP4-2A, driven by a seed-specific promoter PNAP, and engineered into a rapeseed elite cultivar ZS10 with canola quality background. The mean ALA content in the seed oil of PNAP:PfFAD2-PfFAD3 (N23) T5 lines was 3.34-fold that of the control (32.08 vs 9.59%), with the best line being up to 37.47%. There are no significant side effects of the engineered constructs on the background traits including oil content. In fatty acid biosynthesis pathways, the expression levels of structural genes as well as regulatory genes were significantly upregulated in N23 lines. On the other hand, the expression levels of genes encoding the positive regulators of flavonoid-proanthocyanidin biosynthesis but negative regulators of oil accumulation were significantly downregulated. Surprisingly, the ALA level in PfFAD2-PfFAD3 transgenic rapeseed lines driven by the constitutive promoter PD35S was not increased or even showed a slight decrease due to the lower level of foreign gene expression and downregulation of the endogenous orthologous genes BnFAD2 and BnFAD3.
Assuntos
Brassica napus , Brassica rapa , Perilla , Humanos , Brassica napus/genética , Brassica napus/metabolismo , Ácido alfa-Linolênico/química , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Brassica rapa/genética , Brassica rapa/metabolismo , Sementes/genética , Sementes/metabolismo , Óleos/metabolismoRESUMO
Chia (Salvia hispanica) is a functional food crop with high α-linolenic acid (ALA), the omega-3 essential fatty acid, but its worldwide plantation is limited by cold-intolerance and strict short-photoperiod flowering feature. Fatty acid desaturases (FADs) are responsible for seed oil accumulation, and play important roles in cold stress tolerance of plants. To date, there is no report on systemically genome-wide analysis of FAD genes in chia (ShiFADs). In this study, 31 ShiFAD genes were identified, 3 of which contained 2 alternative splicing transcripts, and they were located in 6 chromosomes of chia. Phylogenetic analysis classified the ShiFAD proteins into 7 groups, with conserved gene structure and MEME motifs within each group. Tandem and segmental duplications coursed the expansion of ShiFAD genes. Numerous cis-regulatory elements, including hormone response elements, growth and development elements, biotic/abiotic stress response elements, and transcription factor binding sites, were predicted in ShiFAD promoters. 24 miRNAs targeting ShiFAD genes were identified at whole-genome level. In total, 15 SSR loci were predicted in ShiFAD genes/promoters. RNA-seq data showed that ShiFAD genes were expressed in various organs with different levels. qRT-PCR detection revealed the inducibility of ShiSAD2 and ShiSAD7 in response to cold stress, and validated the seed-specific expression of ShiSAD11a. Yeast expression of ShiSAD11a confirmed the catalytic activity of its encoded protein, and its heterologous expression in Arabidopsis thaliana significantly increased seed oleic acid content. This work lays a foundation for molecular dissection of chia high-ALA trait and functional study of ShiFAD genes in cold tolerance.
Assuntos
Ácidos Graxos Dessaturases , Salvia , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Salvia hispanica , Filogenia , Salvia/genética , Salvia/metabolismo , Óleos de Plantas/química , Sementes/metabolismoRESUMO
MYB transcription factors are major actors regulating plant development and adaptability. Brassica napus is a staple oil crop and is hampered by lodging and diseases. Here, four B. napus MYB69 (BnMYB69s) genes were cloned and functionally characterized. They were dominantly expressed in stems during lignification. BnMYB69 RNA interference (BnMYB69i) plants showed considerable changes in morphology, anatomy, metabolism and gene expression. Stem diameter, leaves, roots and total biomass were distinctly larger, but plant height was significantly reduced. Contents of lignin, cellulose and protopectin in stems were significantly reduced, accompanied with decrease in bending resistance and Sclerotinia sclerotiorum resistance. Anatomical detection observed perturbation in vascular and fiber differentiation in stems, but promotion in parenchyma growth, accompanied with changes in cell size and cell number. In shoots, contents of IAA, shikimates and proanthocyanidin were reduced, while contents of ABA, BL and leaf chlorophyll were increased. qRT-PCR revealed changes in multiple pathways of primary and secondary metabolisms. IAA treatment could recover many phenotypes and metabolisms of BnMYB69i plants. However, roots showed trends opposite to shoots in most cases, and BnMYB69i phenotypes were light-sensitive. Conclusively, BnMYB69s might be light-regulated positive regulators of shikimates-related metabolisms, and exert profound influences on various internal and external plant traits.
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Non-specific lipid transfer proteins (nsLTPs) are small cysteine-rich basic proteins which play essential roles in plant growth, development and abiotic/biotic stress response. However, there is limited information about the nsLTP gene (BnLTP) family in rapeseed (Brassica napus). In this study, 283 BnLTP genes were identified in rapeseed, which were distributed randomly in 19 chromosomes of rapeseed. Phylogenetic analysis showed that BnLTP proteins were divided into seven groups. Exon/intron structure and MEME motifs both remained highly conserved in each BnLTP group. Segmental duplication and hybridization of rapeseed's two sub-genomes mainly contributed to the expansion of the BnLTP gene family. Various potential cis-elements that respond to plant growth, development, biotic/abiotic stresses, and phytohormone signals existed in BnLTP gene promoters. Transcriptome analysis showed that BnLTP genes were expressed in various tissues/organs with different levels and were also involved in the response to heat, drought, NaCl, cold, IAA and ABA stresses, as well as the treatment of fungal pathogens (Sclerotinia sclerotiorum and Leptosphaeria maculans). The qRT-PCR assay validated the results of RNA-seq expression analysis of two top Sclerotinia-responsive BnLTP genes, BnLTP129 and BnLTP161. Moreover, batches of BnLTPs might be regulated by BnTT1 and BnbZIP67 to play roles in the development, metabolism or adaptability of the seed coat and embryo in rapeseed. This work provides an important basis for further functional study of the BnLTP genes in rapeseed quality improvement and stress resistance.
Assuntos
Brassica napus , Brassica rapa , Brassica napus/metabolismo , Brassica rapa/genética , Brassica rapa/metabolismo , Regulação da Expressão Gênica de Plantas , Família Multigênica , Filogenia , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genéticaRESUMO
Plastidial Δ12 fatty acid desaturase (FAD6) is a key enzyme for linoleic acid (LA) and α-linolenic acid (ALA) biosynthesis. Chia (Salvia hispanica L.) is a revived omega-3 plant source that is richest in ALA level. In this study, based on the RACE method, one full-length cDNA sequence encoding FAD6, named ShFAD6, was isolated from chia. There exist three alternative transcription start sites and five alternative poly(A) tailing sites in ShFAD6. The 5'UTR of ShFAD6 contains a purine-stretch of 44 bp. ShFAD6 has an ORF of 1335 bp encoding a 444 aa protein of 51.33 kDa. ShFAD6 contains a conserved Delta12-FADS-like domain together with three strong trans-membrane helices and three histidine motifs. There also exists a chloroplast transmit peptide in ShFAD6 N-terminal. Phylogenetic analyses validated its identity of dicot FAD6 protein and suggested some critical evolutionary features of plant FAD6 genes. Heterologous yeast expression confirmed the catalytic activity of ShFAD6. The qRT-PCR assay showed that ShFAD6 is mainly expressed in leaves, stems, flowers, buds and early-stage seeds, and also responded to various stresses and hormone treatments. Under Sclerotinia infection, qRT-PCR and fluorescence imaging illustrated the possible correlation of ShFAD6 expression and photosynthesis. This study provides insight for further function study of ShFAD6 in oil quality improvement in staple oilseed crops as well as stress response and adaptation in plants.
Assuntos
Ácidos Graxos Dessaturases/metabolismo , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/genética , Proteínas de Plantas/metabolismo , Salvia/metabolismo , Sequência de Aminoácidos , Ascomicetos/fisiologia , Sequência de Bases , Clonagem Molecular , Ácidos Graxos Dessaturases/genética , Filogenia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Salvia/genética , Salvia/crescimento & desenvolvimento , Salvia/microbiologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Sementes/microbiologia , Homologia de Sequência de AminoácidosRESUMO
Cadmium (Cd) tolerance mechanisms in plant are mainly divided into two categories: evasion mechanism and tolerance mechanism. However, due to the complexity of the mechanism of Cd absorption and accumulation in crops, there are still disputes and controversies about Cd toxicity to plants and the mechanism of Cd tolerance in plants. The Cd absorption and accumulation mechanism in edible parts of pepper remains unknown. The present study characterized three pepper cultivars with different cadmium tolerance under cadmium stress. One high-Cd-accumulation type (X55), a medium-Cd-accumulation type (Daguo 99) and a low-Cd-accumulation type (Luojiao 318) were selected to study distribution characteristics of Cd in subcellular fractions of the three pepper varieties as well as expression difference of key Cd accumulation and tolerance genes under different cadmium levels. The results showed that under Cd stress, X55 and Daguo 99 mainly migrated Cd from root to stems and leaves, while Luojiao318 migrated it to the fruit. The Cd concentration in the subcellular fractions of pepper roots, stems, leaves and fruits was as follow: cell wall (F1) > organelle (F2) > cell soluble fraction (F3). The roots, stems and leaf cells of X55 have strong Cd compartmentalization capacity. The fruit cells of Daguo 99 have strong Cd compartmentalization capacity, while the roots of Luojiao318 have strong ability to inhibit Cd absorption. Under Cd stress, HMA1, HMA2 and NRAMP1-6 were up-regulated in roots, stems and fruits of the three varieties. FTP1-2 and FTP1-3 genes were significantly up-regulated in different materials, except the roots of Daguo 99. Under Cd treatment, PCS gene expression of pepper showed an order of that of X55 > Luojiao 318 >Daguo 99. The present study revealed that the cell wall of pepper played an important role in Cd separation and resistance. The difference in Cd accumulation ability of the pepper varieties may be related to differences in main expression sites and expression levels of HMA, NRAMP, FTP and PCS genes.
RESUMO
Sclerotinia sclerotiorum (Ss) is a devastating fungal pathogen that causes Sclerotinia stem rot in rapeseed (Brassica napus), and is also detrimental to mulberry and many other crops. A wild mulberry germplasm, Morus laevigata, showed high resistance to Ss, but the molecular basis for the resistance is largely unknown. Here, the transcriptome response characteristics of M. laevigata to Ss infection were revealed by RNA-seq. A total of 833 differentially expressed genes (DEGs) were detected after the Ss inoculation in the leaf of M. laevigata. After the GO terms and KEGG pathways enrichment analyses, 42 resistance-related genes were selected as core candidates from the upregulated DEGs. Their expression patterns were detected in the roots, stems, leaves, flowers, and fruits of M. laevigata. Most of them (30/42) were specifically or mainly expressed in flowers, which was consistent with the fact that Ss mainly infects plants through floral organs, and indicated that Ss-resistance genes could be induced by pathogen inoculation on ectopic organs. After the Ss inoculation, these candidate genes were also induced in the two susceptible varieties of mulberry, but the responses of most of them were much slower with lower extents. Based on the expression patterns and functional annotation of the 42 candidate genes, we cloned the full-length gDNA and cDNA sequences of the Ss-inducible chitinase gene set (MlChi family). Phylogenetic tree construction, protein interaction network prediction, and gene expression analysis revealed their special roles in response to Ss infection. In prokaryotic expression, their protein products were all in the form of an inclusion body. Our results will help in the understanding of the molecular basis of Ss-resistance in M. laevigata, and the isolated MlChi genes are candidates for the improvement in plant Ss-resistance via biotechnology.
Assuntos
Ascomicetos/patogenicidade , Quitinases/genética , Morus/genética , Ascomicetos/genética , Ascomicetos/metabolismo , Ascomicetos/fisiologia , Quitinases/metabolismo , Resistência à Doença/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Morus/metabolismo , Filogenia , Doenças das Plantas/microbiologia , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Transcriptoma/genéticaRESUMO
Arabidopsis thaliana MYB43 (AtMYB43) is suggested to be involved in cell wall lignification. PtrMYB152, the Populus orthologue of AtMYB43, is a transcriptional activator of lignin biosynthesis and vessel wall deposition. In this research, MYB43 genes from Brassica napus (rapeseed) and its parental species B. rapa and B. oleracea were molecularly characterized, which were dominantly expressed in stem and other vascular organs and showed responsiveness to Sclerotinia sclerotiorum infection. The BnMYB43 family was silenced by RNAi, and the transgenic rapeseed lines showed retardation in growth and development with smaller organs, reduced lodging resistance, fewer silique number and lower yield potential. The thickness of the xylem layer decreased by 28%; the numbers of sclerenchymatous cells, vessels, interfascicular fibers, sieve tubes and pith cells in the whole cross section of the stem decreased by 28%, 59%, 48%, 34% and 21% in these lines, respectively. The contents of cellulose and lignin decreased by 17.49% and 16.21% respectively, while the pectin content increased by 71.92% in stems of RNAi lines. When inoculated with S. sclerotiorum, the lesion length was drastically decreased by 52.10% in the stems of transgenic plants compared with WT, implying great increase in disease resistance. Correspondingly, changes in the gene expression patterns of lignin biosynthesis, cellulose biosynthesis, pectin biosynthesis, cell cycle, SA- and JA-signals, and defensive pathways were in accordance with above phenotypic modifications. These results show that BnMYB43, being a growth-defense trade-off participant, positively regulates vascular lignification, plant morphology and yield potential, but negatively affects resistance to S. sclerotiorum. Moreover, this lignification activator influences cell biogenesis of both lignified and non-lignified tissues of the whole vascular organ.
Assuntos
Proteínas de Arabidopsis/genética , Ascomicetos/genética , Brassica napus/genética , Doenças das Plantas/genética , Fatores de Transcrição/genética , Arabidopsis/genética , Ascomicetos/patogenicidade , Brassica napus/crescimento & desenvolvimento , Brassica napus/microbiologia , Parede Celular/genética , Parede Celular/microbiologia , Celulose/biossíntese , Resistência à Doença/genética , Lignina/biossíntese , Pectinas/biossíntese , Doenças das Plantas/microbiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Interferência de RNA , Xilema/genética , Xilema/crescimento & desenvolvimentoRESUMO
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 Plantas/farmacologia , Sequências Reguladoras de Ácido Nucleico/genética , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Sintenia/genéticaRESUMO
Brassica napus (2n = 4x = 38, AACC) is an important allopolyploid crop derived from interspecific crosses between Brassica rapa (2n = 2x = 20, AA) and Brassica oleracea (2n = 2x = 18, CC). However, no truly wild B. napus populations are known; its origin and improvement processes remain unclear. Here, we resequence 588 B. napus accessions. We uncover that the A subgenome may evolve from the ancestor of European turnip and the C subgenome may evolve from the common ancestor of kohlrabi, cauliflower, broccoli, and Chinese kale. Additionally, winter oilseed may be the original form of B. napus. Subgenome-specific selection of defense-response genes has contributed to environmental adaptation after formation of the species, whereas asymmetrical subgenomic selection has led to ecotype change. By integrating genome-wide association studies, selection signals, and transcriptome analyses, we identify genes associated with improved stress tolerance, oil content, seed quality, and ecotype improvement. They are candidates for further functional characterization and genetic improvement of B. napus.
Assuntos
Aclimatação/genética , Brassica napus/genética , Loci Gênicos , Genoma de Planta/genética , Melhoramento Vegetal , Brassica rapa/genética , Cromossomos de Plantas , Ecótipo , Perfilação da Expressão Gênica , Especiação Genética , Sementes/genética , Sequenciamento Completo do GenomaRESUMO
Pot experiment was conducted to study the difference of cadmium uptake and OAS and IRT genes' expression between the two ryegrass varieties under cadmium stress. The results showed that with the increase of cadmium levels, the dry weights of roots of the two ryegrass varieties, and the dry weights of shoots and plants of Abbott first increased and then decreased. When exposed to 75 mg kg-1 Cd, the dry weights of shoot and plant of Abbott reached the maximum, which increased by 11.13 and 10.67% compared with the control. At 75 mg kg-1 Cd, cadmium concentrations in shoot of the two ryegrass varieties were higher than the critical value of Cd hyperaccumulator (100 mg kg-1), 111.19 mg kg-1 (Bond), and 133.69 mg kg-1 (Abbott), respectively. The OAS gene expression in the leaves of the two ryegrass varieties showed a unimodal curve, which was up to the highest at the cadmium level of 150 mg kg-1, but fell back at high cadmium levels of 300 and 600 mg kg-1. The OAS gene expression in Bond and Abbott roots showed a bimodal curve. The OAS gene expression in Bond root and Abbott stem mainly showed a unimodal curve. The expression of IRT genes family in the leaves of ryegrass varieties was basically in line with the characteristics of unimodal curve, which was up to the highest at cadmium level of 75 or 150 mg kg-1, respectively. The IRT expression in the ryegrass stems showed characteristics of bimodal and unimodal curves, while that in the roots was mainly unimodal. The expression of OAS and IRT genes was higher in Bond than that in Abbott due to genotype difference between the two varieties. The expression of OAS and IRT was greater in leaves than that in roots and stems. Ryegrass tolerance to cadmium can be increased by increasing the expression of OAS and IRT genes in roots and stems, and transfer of cadmium from roots and stems to the leaves can be enhanced by increasing expression OAS and IRT in leaves.
Assuntos
Cádmio/farmacocinética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lolium/efeitos dos fármacos , Poluentes do Solo/farmacocinética , Proteínas de Transporte de Cátions/genética , Lolium/genética , Lolium/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Caules de Planta/efeitos dos fármacos , Caules de Planta/genética , Serina/análogos & derivados , Serina/genéticaRESUMO
In order to understand the mechanism of the difference of Cd absorption and Cd enrichment in different ryegrass varieties, pot experiment was conducted to study on the response of two varieties of ryegrass (Bond and Abbott) to Cd stress as well as the differences of Cd uptake and expression of MT family genes and NRAMP2. Results showed that root dry weights of two varieties and shoot dry weights of Abbott increased first and then decreased with the increase of Cd level in soil. When exposed to 75 mg kg-1 Cd, shoot dry weight and plant dry weight of Abbott both reached maximum values (10.92 and 12.03 g pot-1), which increased by 11.09 and 10.67% compared with the control, respectively. Shoot dry weight and plant dry weight of Bond decreased with the increase of Cd level in soil. When the Cd level in soil was 75 mg kg-1, shoot Cd concentrations of the two varieties were 111.19 mg kg-1 (Bond) and 133.69 mg kg-1 (Abbott), respectively, both of which exceeded the critical value of Cd hyperaccumulator (100 mg kg-1). The expression of MT gene family and NRAMP2 in the leaf of Bond variety significantly increased at the Cd level of 75 mg kg-1 and reached maximum value (except MT2C) at Cd level of 150 mg kg-1. The expression of MT gene family in the stem of Bond variety showed a double-peak pattern, while the expression of NRAMP2 was a single-peak pattern. The expression of MT gene family and NRAMP2 in Abbott variety was consistent with single-peak pattern. The expression of MT gene family and NRAMP2 in leaf both significantly increased at Cd level of 150 mg kg-1, while that in stem and root significantly increased at Cd level of 75 mg kg-1. For both varieties of ryegrass, the expression amount of MT family genes and Nramp2 in leaf was higher than that in root and stem, indicating the Cd tolerance of ryegrass can be improved by increasing the expression levels of MT family genes and Nramp2 in stem and root. There was significant genotypic difference in the expression of MT gene family and NRAMP2 between the two varieties of ryegrass, and the expression of MT gene family and NRAMP2 in leaves and stems of Bond variety was higher than that in Abbott variety, while the expression of MT gene family and NRAMP2 in roots of Abbott variety was higher than that in Bond variety. The two gene families investigated in this study may be closely related to Cd uptake, but not related to Cd transport from root to leaf and Cd enrichment in shoot.
Assuntos
Cádmio/farmacocinética , Lolium/efeitos dos fármacos , Lolium/metabolismo , Proteínas de Plantas/genética , Poluentes do Solo/farmacocinética , Proteínas de Transporte de Cátions/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lolium/genética , Metalotioneína/genética , Família Multigênica , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Solo/química , Especificidade da EspécieRESUMO
Omega-3 fatty acid desaturase (ω-3 FAD, D15D) is a key enzyme for α-linolenic acid (ALA) biosynthesis. Both chia (Salvia hispanica) and perilla (Perilla frutescens) contain high levels of ALA in seeds. In this study, the ω-3 FAD gene family was systematically and comparatively cloned from chia and perilla. Perilla FAD3, FAD7, FAD8 and chia FAD7 are encoded by single-copy (but heterozygous) genes, while chia FAD3 is encoded by 2 distinct genes. Only 1 chia FAD8 sequence was isolated. In these genes, there are 1 to 6 transcription start sites, 1 to 8 poly(A) tailing sites, and 7 introns. The 5'UTRs of PfFAD8a/b contain 1 to 2 purine-stretches and 2 pyrimidine-stretches. An alternative splice variant of ShFAD7a/b comprises a 5'UTR intron. Their encoded proteins harbor an FA_desaturase conserved domain together with 4 trans-membrane helices and 3 histidine boxes. Phylogenetic analysis validated their identity of dicot microsomal or plastidial ω-3 FAD proteins, and revealed some important evolutionary features of plant ω-3 FAD genes such as convergent evolution across different phylums, single-copy status in algae, and duplication events in certain taxa. The qRT-PCR assay showed that the ω-3 FAD genes of two species were expressed at different levels in various organs, and they also responded to multiple stress treatments. The functionality of the ShFAD3 and PfFAD3 enzymes was confirmed by yeast expression. The systemic molecular and functional features of the ω-3 FAD gene family from chia and perilla revealed in this study will facilitate their use in future studies on genetic improvement of ALA traits in oilseed crops.
Assuntos
Ácidos Graxos Dessaturases/genética , Genes de Plantas , Perilla frutescens/enzimologia , Perilla frutescens/genética , Proteínas de Plantas/genética , Salvia/enzimologia , Salvia/genética , Regiões 5' não Traduzidas , Processamento Alternativo , Sequência de Aminoácidos , Clonagem Molecular , Sequência Conservada , Evolução Molecular , Ácidos Graxos Dessaturases/química , Ácidos Graxos Dessaturases/metabolismo , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Família Multigênica , Especificidade de Órgãos , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Estresse Fisiológico , TranscriptomaRESUMO
Rapeseed (Brassica napus) is an important oilseed crop worldwide, and fatty acid (FA) compositions determine the nutritional and economic value of its seed oil. Fatty acid desaturases (FADs) play a pivotal role in regulating FA compositions, but to date, no comprehensive genome-wide analysis of FAD gene family in rapeseed and its parent species has been reported. In this study, using homology searches, 84, 45, and 44 FAD genes were identified in rapeseed, Brassica rapa, and Brassica oleracea genomes, respectively. These FAD genes were unevenly located in 17 chromosomes and 2 scaffolds of rapeseed, 9 chromosomes and 1 scaffold of B. rapa, and all the chromosomes of B. oleracea. Phylogenetic analysis showed that the soluble and membrane-bound FADs in the three Brassica species were divided into four and six subfamilies, respectively. Generally, the soluble FADs contained two conserved histidine boxes, while three highly conserved histidine boxes were harbored in membrane-bound FADs. Exon-intron structure, intron phase, and motif composition and position were highly conserved in each FAD subfamily. Putative subcellular locations of FAD proteins in three Brassica species were consistent with those of corresponding known FADs. In total, 25 of simple sequence repeat (SSR) loci were found in FAD genes of the three Brassica species. Transcripts of selected FAD genes in the three species were examined in various organs/tissues or stress treatments from NCBI expressed sequence tag (EST) database. This study provides a critical molecular basis for quality improvement of rapeseed oil and facilitates our understanding of key roles of FAD genes in plant growth and development and stress response.
Assuntos
Brassica napus/genética , Ácidos Graxos Dessaturases/genética , Genoma de Planta , Família Multigênica , Proteínas de Plantas/genética , Brassica napus/enzimologia , Estudo de Associação Genômica AmplaRESUMO
ABSTRACT: The mysterious ancient Mesoamerican Indian crop chia (Salvia hispanica) is revived and expanding worldwide due to its richness of valuable nutraceuticals such as α-linolenic acid (ALA), antioxidants, food fiber, gels, and proteins. We carried out a pilot experiment on chia planting in non-frost Sichuan Basin, at Hechuan Base (30˚0′ 43″ N, 106˚7′ 41″ E, 216 m), Southwest University, Chongqing, China. The split-plot trial contained two factors, 3 spring-summer sowing times as main plots, and 6 densities as subplots, with 3 replicates. Phenological, botanical, adversity, yield, and seed quality traits were investigated. Plants were very tall, suffered from lodging, and flowered in mid-October. Sichuan Basin can be considered as a north edge for growing chia, with low yield (680 kg/hectare) because of insufficient seed filling and maturation in autumn-winter season (1000-seed weight of 1.14 g). However, its ALA content is 5 percent points higher than the seed-donor commercial bottle (65.06%/63.96% VS 59.35%/59.74% for black/white seeds), accompanied by decrease oleic and stearic acid, while linoleic acid and palmitic acid are equivalent. Considering its short-day habit, it is recommended to try sowing in middle summer (from late June to early August) to avoid too long growing period, excessive vegetative growth, and waste of field and climate resources caused by spring-summer sowing. Furthermore, winter sowing of chia with mulch cover could also be tried, with an expectation of harvesting in summer. Most importantly, only when the photoperiod-insensitive early flowering stocks are created, chia can be recommended as a low-risk crop to the farmers of this region.
RESUMO: A chia (Salvia hispanica) é cultivada em todo o mundo por sua riqueza de nutrientes nutracêuticos valiosos, tais como a-ácido linolênico (ALA), antioxidantes, fibras alimentares, géis e proteínas. Entretanto, não há informações sobre sua performance agronômica se cultivada aos 30˚N na China. Assim, realizou-se um experimento com o cultivo de chia na base Hechuan (30°0'43"N, 106°7'41"E, 216m, que não apresenta geada) da Southwest University, Chongqing, China. O delineamento em parcela subdividida contém dois fatores,três épocas de semeadura na primavera-verão como parcelas principais e seis densidades de sementes como subparcelas, com três repetições. Foram investigados os caracteres fenológicos, botânicos, de adversidade, rendimento e qualidade da semente. As plantas se tornaram altas, acamarame floresceram em meados de outubro. A bacia de Sichuan pode ser considerada como uma fronteira limítrofe norte para o crescimento da chia, com baixo rendimento (680kg ha-1) devido ao enchimento e amadurecimento insuficientes na estação outono-inverno (peso de 1000 sementes de 1,14g). No entanto, o seu conteúdo de ALA é de 5 pontos percentuais mais elevado do que a semente comercial, 65,06%/63,96% contra 59,35%/59,74% para as sementes pretas/brancas, respectivamente, acompanhado por diminuição de ácido oleico e ácido esteárico, enquanto que o ácido linoleico e o ácido palmítico são equivalentes. Considerando o seu hábito de dia curto, recomenda-se semear no meio do verão,de junho a início de agosto, para evitar um tempo de cultivo muito longo, desenvolvimento vegetativo excessivo e desperdício de recursos de campo e clima causados pela semeadura de primavera-verão. Além disso, a semeadura de inverno da chia com cobertura morta também poderia ser realizada, com expectativa de colheita no verão. Mais importante ainda, somente quando os estoques de floração precoce insensíveis ao fotoperíodo são criados, pode-se recomendar como uma cultura de baixo risco para os agricultores desta região.
RESUMO
TRANSPARENT TESTA1 (TT1) is a zinc finger protein that contains a WIP domain. It plays important roles in controlling differentiation and pigmentation of the seed coat endothelium, and can affect the expression of early biosynthetic genes and late biosynthetic genes of flavonoid biosynthesis in Arabidopsis thaliana. In Brassica napus (AACC, 2n=38), the functions of BnTT1 genes remain unknown and few studies have focused on their roles in fatty acid (FA) biosynthesis. In this study, BnTT1 family genes were silenced by RNA interference, which resulted in yellow rapeseed, abnormal testa development (a much thinner testa), decreased seed weight, and altered seed FA composition in B. napus. High-throughput sequencing of genes differentially expressed between developing transgenic B. napus and wild-type seeds revealed altered expression of numerous genes involved in flavonoid and FA biosynthesis. As a consequence of this altered expression, we detected a marked decrease of oleic acid (C18:1) and notable increases of linoleic acid (C18:2) and α-linolenic acid (C18:3) in mature transgenic B. napus seeds by gas chromatography and near-infrared reflectance spectroscopy. Meanwhile, liquid chromatography-mass spectrometry showed reduced accumulation of flavonoids in transgenic seeds. Therefore, we propose that BnTT1s are involved in the regulation of flavonoid biosynthesis, and may also play a role in FA biosynthesis in B. napus.
Assuntos
Brassica napus/genética , Ácidos Graxos/metabolismo , Flavonoides/biossíntese , Proteínas de Plantas/fisiologia , Brassica napus/metabolismo , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Biologia Computacional , Flavonoides/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Espectrometria de Massas , Família Multigênica , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes/genética , Sementes/metabolismoRESUMO
Mitogen-activated protein kinase (MAPK) cascades are fundamental signal transduction modules in plants, controlling cell division, development, hormone signaling, and biotic and abiotic stress responses. Although MAPKs have been investigated in several plant species, a comprehensive analysis of the MAPK gene family has hitherto not been performed in Brassica rapa. In this study, we identified 32 MAPKs in the B. rapa genome by conducting BLASTP and syntenic block analyses, and screening for the essential signature motif (TDY or TEY) of plant MAPK proteins. Of the 32 BraMAPK genes retrieved from the Brassica Database, 13 exhibited exon splicing errors, excessive splicing of the 5' sequence, excessive retention of the 5' sequence, and sequencing errors of the 3' end. Phylogenetic trees of the 32 corrected MAPKs from B. rapa and of MAPKs from other plants generated by the neighbor-joining and maximum likelihood methods suggested that BraMAPKs could be divided into four groups (groups A, B, C, and D). Gene number expansion was observed for BraMAPK genes in groups A and D, which may have been caused by the tandem duplication and genome triplication of the ancestral genome of the Brassica progenitor. Except for five members of the BraMAPK10 subfamily, the identified BraMAPKs were expressed in most of the tissues examined, including callus, root, stem, leaf, flower, and silique. Quantitative real-time PCR demonstrated that at least six and five BraMAPKs were induced or repressed by various abiotic stresses and hormone treatments, respectively, suggesting their potential roles in the abiotic stress response and various hormone signal transduction pathways in B. rapa. This study provides valuable insight into the putative physiological and biochemical functions of MAPK genes in B. rapa.