RESUMEN
Background: Anoectochilus roxburghii and Anoectochilus formosanus, belong to the Anoectochilus genus, have been used for Chinese herbal drugs as well as health food. Phenylalanine ammonia-lyase (PAL), the key enzyme in primary metabolism and phenylpropanoid metabolism, produces secondary metabolites (flavonoids) in plants, which are beneficial for the biosynthesis of phenylpropanoid metabolites. Methods: The PAL genes were cloned from A. formosanus and A. roxburghii according to our previous transcriptomic analysis. The PALs were introduced into pCAMBIA2300-35S-PAL-eGFP to generate 35S-PAL-eGFP. The constructs were further used for subcellular localization and transgenic Arabidopsis. The expression of AfPAL and ArPAL under precursor substance (L-Phe), NaCl, UV, and red-light were analyzed by real-time quantitative PCR (RT-qPCR). Results: AfPAL and ArPAL , encoding 2,148 base pairs, were cloned from A. formosanus and A. roxburghii. The subcellular localization showed that the ArPAL and AfPAL were both localized in the nucleus with GPF. Quantitative RT-PCR analysis indicated that the ArPAL and AfPAL genes function in the phenylalanine pathway as well as response to induced conditions. Overexpression of the AfPAL and ArPAL could increase flavonoids and anthocyanin content in the transgenic Arabidopsis. Discussion: The results suggest that AfPAL and ArPAL play a crucial role in the flavonoid biosynthesis in Anoectochilus. Also, our study provides new insights into the enrichment of secondary metabolites of traditional Chinese medicines A. formosanus and A. roxburghii, which can improve their medicinal active ingredients and be used for drug discovery in plants.
Asunto(s)
Arabidopsis , Orchidaceae , Plantas Medicinales , Fenilanina Amoníaco-Liasa/genética , Arabidopsis/genética , Plantas Medicinales/genética , Flavonoides , Orchidaceae/metabolismoRESUMEN
Anoectochilus roxburghii and Anoectochilus formasanus are the major species of genus Anoectochilus used in traditional Chinese medicine for their abundant content of flavonoids and some other medicinal constituents. In recent years, their wild resources are gradually exhausted due to over-collection and ecological deterioration. Artificial cultivation and tissue culture are employed to increase production. In this study, the open reading frame, promoter and genomic sequences of the chalcone synthase (CHS) gene were cloned from these two species according to their transcriptome information, and used for expression analysis in response to the induction of phenylalanine, ultraviolet light and NaCl, and its effect investigation on accumulation of flavonoids. The results showed that the expression of the CHS genes was upregulated in response to these inductions and resulted in increasing accumulation of total flavonoids. However, the increased flavonoids induced by phenylalanine and ultraviolet light were mainly allocated into the anthocyanidin branch of flavonoids biosynthesis. Not only did it improved the medicinal value, but might have inhibitory effect on plant growth because of the increased malondialdehyde accumulation. Under the induction of appropriate concentration of NaCl, the medicinal constituents of flavonoids were increased without inhibition to plant growth.
Asunto(s)
Aciltransferasas/genética , Aciltransferasas/metabolismo , Flavonoides/metabolismo , Regulación de la Expresión Génica de las Plantas , Plantas Medicinales/genética , Plantas Medicinales/metabolismo , Aciltransferasas/química , Secuencia de Aminoácidos , Clonación Molecular , FilogeniaRESUMEN
Calcium-dependent protein kinase (CPKs) is a key player in the calcium signaling pathway to decode calcium signals into various physiological responses. cDNA sequences of 9 ZmCPK genes were successfully cloned from all four phylogenetic groups in maize. qRT-PCR analysis showed the expression variation of these selected genes under abscisic acid (ABA) and calcium chloride (CaCl2) treatment. Due to the presence of N-myristoylation/palmitoylation sites, the selected ZmCPK members were localized in a plasma membrane. To clarify whether ZmCPK, a key player in calcium signaling, interacts with key players of ABA, protein phosphatase 2Cs (PP2Cs) and the SNF1-related protein kinase 2s (SnRK2s) and mitogen-activated protein kinase (MAPK) signaling pathways in maize, we examined the interaction between 9 CPKs, 8 PP2Cs, 5 SnRKs, and 20 members of the MPK family in maize by using yeast two-hybrid assay. Our results showed that three ZmCPKs interact with three different members of ZmSnRKs while four ZmCPK members had a positive interaction with 13 members of ZmMPKs in different combinations. These four ZmCPK proteins are from three different groups in maize. These findings of physical interactions between ZmCPKs, ZmSnRKs, and ZmMPKs suggested that these signaling pathways do not only have indirect influence but also have direct crosstalk that may involve the defense mechanism in maize. The present study may improve the understanding of signal transduction in plants.
Asunto(s)
Proteínas de Plantas/metabolismo , Proteínas Quinasas/metabolismo , Zea mays/enzimología , Zea mays/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Proteínas de Plantas/genética , Proteínas Quinasas/genética , Transducción de Señal/genética , Transducción de Señal/fisiologíaRESUMEN
Brassinosteroid (BR) is a class of plant-specific steroidal hormone and plays vital roles in plant growth, developmental and stress response. As the core component of BR signaling, the BES1/BZR1 transcription factors are activated by the BR signal, bind to the E-box (CANNTG) or BRRE element (CGTGT/CG) enriched in the promoter of downstream target genes and regulate their expression. Besides BR signal transduction, BES1/BZR1s are also involved in other signaling pathways such as abscisic acid, gibberellin and light to co-regulate plant growth and development. Recently, BES1/BZR1s were found to be related to stress resistance. In this review, we summarize recent advances of molecular mechanism of the BES1/BZR1 transcription factors regulating plant growth, development and stress resistance through signal transduction to provide a reference for related researches.
Asunto(s)
Brasinoesteroides , Proteínas Nucleares/fisiología , Reguladores del Crecimiento de las Plantas , Proteínas de Plantas/fisiología , Factores de Transcripción/fisiología , Regulación de la Expresión Génica de las Plantas , Plantas , Transducción de Señal , Estrés FisiológicoRESUMEN
KEY MESSAGE: We defined a comprehensive core ABA signaling network in monocot maize, including the gene expression, subcellular localization and interaction network of ZmPYLs, ZmPP2Cs, ZmSnRK2s and the putative substrates. The phytohormone abscisic acid (ABA) plays an important role in plant developmental processes and abiotic stress responses. In Arabidopsis, ABA is sensed by the PYL ABA receptors, which leads to binding of the PP2C protein phosphatase and activation of the SnRK2 protein kinases. These components functioning diversely and redundantly in ABA signaling are little known in maize. Using Arabidopsis pyl112458 and snrk2.2/3/6 mutants, we identified several ABA-responsive ZmPYLs and ZmSnRK2s, and also ZmPP2Cs. We showed the gene expression, subcellular localization and interaction network of ZmPYLs, ZmPP2Cs, and ZmSnRK2s, and the isolation of putative ZmSnRK2 substrates by mass spectrometry in monocot maize. We found that the ABA dependency of PYL-PP2C interactions is contingent on the identity of the PP2Cs. Among 238 candidate substrates for ABA-activated protein kinases, 69 are putative ZmSnRK2 substrates. Besides homologs of previously reported putative AtSnRK2 substrates, 23 phosphoproteins have not been discovered in the dicot Arabidopsis. Thus, we have defined a comprehensive core ABA signaling network in monocot maize and shed new light on ABA signaling.
Asunto(s)
Ácido Abscísico/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/metabolismo , Transducción de Señal , Zea mays/metabolismo , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Reguladores del Crecimiento de las Plantas/metabolismo , Proteínas de Plantas/genética , Mapas de Interacción de Proteínas , Zea mays/genética , Zea mays/crecimiento & desarrolloRESUMEN
MAIN CONCLUSION: A phospholipase Dα gene ( AnPLDα ) was cloned from xerophytic desert plant Ammopiptanthus nanus and its overexpression enhanced salt tolerance of a PLDα1 deficient Arabidopsis mutant. Phospholipase Dα (PLDα) hydrolyzes phosphatidylcholine to produce phosphatidic acid, and plays crucial role in plant tolerance to abiotic stress. In this study, a phospholipase Dα gene (AnPLDα) was cloned from xerophyte Ammopiptanthus nanus by the methods of homologous cloning and rapid amplification of cDNA ends, and evaluated for its function in stress tolerance. The full-length cDNA was 2832 bp long, containing an open reading frame of 2427 bp that encodes 808 amino acids. The putative protein was predicted to be localized to the cytoplasm and this was confirmed by transient expression of a fluorescent fusion protein. The endogenous expression of the AnPLDα gene was induced by high salt, dehydration, cold and abscisic acid. The heterologous expression of the AnPLDα gene improved salt tolerance of an Arabidopsis pldα1 knocked out mutant, and positively regulated the expression of the AtABI, AtNCED, AtRD29A, AtRD29B and AtADH genes. Therefore, the AnPLDα gene was concluded to be involved in response to abiotic stress. The AnPLDα gene is a hopeful candidate for transgenic application to improve stress tolerance of commercial crops.
Asunto(s)
Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Fabaceae/enzimología , Fabaceae/genética , Fosfolipasas , Tolerancia a la Sal/fisiología , Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/genética , Fosfolipasas/genética , Fosfolipasas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/efectos de los fármacos , Plantas Modificadas Genéticamente/enzimología , Plantas Modificadas Genéticamente/genética , Tolerancia a la Sal/genética , Cloruro de Sodio/farmacologíaRESUMEN
KEY MESSAGE: The molybdenum cofactor sulfurase gene ( AnMCSU ) was cloned from xerophytic desert plant Ammopiptanthus nanus and validated for its function of tolerance toward abiotic stresses by heterologous expression in Arabidopsis thaliana. Molybdenum cofactor sulfurase participates in catalyzing biosynthesis of abscisic acid, which plays a crucial role in the response of plants to abiotic stresses. In this study, we cloned molybdenum cofactor sulfurase gene (AnMCSU) from a super-xerophytic desert plant, Ammopiptanthus nanus, by using rapid amplification of cDNA ends method. This gene has a total length of 2544 bp, with a 5'- and a 3'-untranslated region of 167 and 88 bp, and an open reading frame of 2289 bp, which encodes an 84.85 kDa protein of 762 amino acids. The putative amino acid sequence shares high homology and conserved amino acid residues crucial for the function of molybdenum cofactor sulfurases with other leguminous species. The encoded protein of the AnMCSU gene was located in the cytoplasm by transient expression in Nicotiana benthamiana. The result of real-time quantitative PCR showed that the expression of the AnMCSU gene was induced by heat, dehydration, high salt stresses, and ABA induction, and inhibited by cold stress. The heterologous expression of the AnMCSU gene significantly enhanced the tolerance of Arabidopsis thaliana to high salt, cold, osmotic stresses, and abscisic acid induction. All these results suggest that the AnMCSU gene might play a crucial role in the adaptation of A. nanus to abiotic stress and has potential to be applied to transgenic improvement of commercial crops.
Asunto(s)
Coenzimas/metabolismo , Fabaceae/enzimología , Fabaceae/genética , Genes de Plantas , Metaloproteínas/metabolismo , Pteridinas/metabolismo , Sulfurtransferasas/genética , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacología , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Coenzimas/genética , Secuencia Conservada , ADN Complementario/genética , Fabaceae/efectos de los fármacos , Fabaceae/fisiología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Germinación/efectos de los fármacos , Homocigoto , Manitol/farmacología , Metaloproteínas/genética , Datos de Secuencia Molecular , Cofactores de Molibdeno , Fenotipo , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Prolina/metabolismo , Estructura Terciaria de Proteína , Reproducibilidad de los Resultados , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Cloruro de Sodio/farmacología , Fracciones Subcelulares/efectos de los fármacos , Fracciones Subcelulares/enzimología , Sulfurtransferasas/química , Sulfurtransferasas/metabolismoRESUMEN
Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. In recent researches, pyrabactin resistance 1-like protein (PYL) and protein phosphatase type 2C (PP2C) were identified as the direct receptor and the second component of ABA signaling pathway, respectively. However, a lot of PYL and PP2C members were found in Arabidopsis and several other plants. Some of them were found not to be involved in ABA signaling. Because of the complex diversity of the genome, few documents have been available on the molecular details of the ABA signal perception system in maize. In the present study, we conducted bioinformatics analysis to find out the candidates (ZmPYL3 and ZmPP2C16) of the PYL and PP2C members most probably involved in ABA signaling in maize, cloned their encoding genes (ZmPYL3 and ZmPP2C16), verified the interaction between these two proteins in response to exogenous ABA induction by yeast two-hybrid assay and bimolecular fluorescence complementation, and investigated the expression patterns of these two genes under the induction of exogenous ABA by real-time fluorescence quantitative PCR. The results indicated that the ZmPYL3 and ZmPP2C16 proteins interacted in vitro and in vivo in response to the induction of exogenous ABA. The downregulated expression of the ZmPYL3 gene and the upregulated expression of the ZmPP2C16 gene are responsive to the induction of exogenous ABA. The ZmPYL3 and ZmPP2C16 proteins are the most probable members of the receptors and the second components of ABA signaling pathway, respectively.
Asunto(s)
Ácido Abscísico/metabolismo , Fosfoproteínas Fosfatasas/genética , Fosfoproteínas Fosfatasas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Zea mays/metabolismo , Clonación Molecular , Biología Computacional , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Genoma de Planta , Filogenia , Proteína Fosfatasa 2C , Transducción de Señal , Técnicas del Sistema de Dos Híbridos , Zea mays/genéticaRESUMEN
Betaine aldehyde dehydrogenase (BADH) catalyzes the synthesis of glycine betaine, a regulator of osmosis, and therefore BADH is considered to play a significant role in response of plants to abiotic stresses. Here, based on the conserved residues of the deduced amino acid sequences of the homologous BADH genes, we cloned the AnBADH gene from the xerophytic leguminous plant Ammopiptanthus nanus by using reverse transcription PCR and rapid amplification of cDNA ends. The full-length cDNA is 1,868 bp long without intron, and contains an open reading frame of 1512 bp, and 3'- and 5'-untranslated regions of 294 and 62 bp. It encodes a 54.71 kDa protein of 503 amino acids. The deduced amino acid sequence shares high homology, conserved amino acid residues and sequence motifs crucial for the function with the BADHs in other leguminous species. The sequence of the open reading frame was used to construct a prokaryotic expression vector pET32a-AnBADH, and transform Escherichia coli. The transformants expressed the heterologous AnBADH gene under the induction of isopropyl ß-D-thiogalactopyranoside, and demonstrated significant enhancement of salt and heat tolerance under the stress conditions of 700 mmol L(-1) NaCl and 55°C high temperature. This result suggests that the AnBADH gene might play a crucial role in adaption of A. nanus to the abiotic stresses, and have the potential to be applied to transgenic operations of commercially important crops for improvement of abiotic tolerance.
Asunto(s)
Betaína Aldehído Deshidrogenasa/metabolismo , Escherichia coli/genética , Escherichia coli/fisiología , Fabaceae/enzimología , Genes de Plantas , Aclimatación , Adaptación Fisiológica , Betaína Aldehído Deshidrogenasa/genética , Clonación Molecular , Fabaceae/clasificación , Fabaceae/genética , Datos de Secuencia Molecular , Filogenia , Hojas de la Planta/genética , Tolerancia a la Sal , Homología de Secuencia de Aminoácido , Cloruro de Sodio , Temperatura , Tiogalactósidos/metabolismo , Transformación GenéticaRESUMEN
Microarray assay of four inbred lines was used to identify 303 microRNAs differentially expressed under drought stress. The microRNAs were used for bioinformatics prediction of their target genes. The majority of the differentially expressed microRNA families showed different expression profiles at different time points of the stress process among the four inbred lines. Digital gene expression profiling revealed 54 genes targeted by 128 of the microRNAs differentially expressed under the same stress conditions. The differential expression of miR159 and miR168 was further validated by locked nucleic acid northern hybridization. These results indicated that miR159 and miR168, as well as numerous other microRNAs, play critical roles in signaling pathways of maize response to drought stress. However, the level of the post-transcriptional regulation mediated by microRNAs had different responses among genotypes, and the gene expression related to signaling pathways under drought stress is also regulated, possibly by multiple mechanisms.
Asunto(s)
Sequías , MicroARNs/genética , Estrés Fisiológico , Transcriptoma , Zea mays/genética , Regulación de la Expresión Génica de las Plantas , MicroARNs/metabolismo , Transducción de Señal , Zea mays/metabolismoRESUMEN
Antifreeze proteins are a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival under the subzero environments. Ammopiptanthus nanus is the unique evergreen broadleaf bush endemic to the Mid-Asia deserts. It survives at the west edge of the Tarim Basin from the disappearance of the ancient Mediterranean in the Tertiary Period. Its distribution region is characterized by the arid climate and extreme temperatures, where the extreme temperatures range from -30 °C to 40 °C. In the present study, the antifreeze protein gene AnAFP of A. nanus was used to transform Escherichia coli and tobacco, after bioinformatics analysis for its possible function. The transformed E. coli strain expressed the heterologous AnAFP gene under the induction of isopropyl ß-D-thiogalactopyranoside, and demonstrated significant enhancement of cold tolerance. The transformed tobacco lines expressed the heterologous AnAFP gene in response to cold stress, and showed a less change of relative electrical conductivity under cold stress, and a less wilting phenotype after 16 h of -3 °C cold stress and thawing for 1h than the untransformed wild-type plants. All these results imply the potential value of the AnAFP gene to be used in genetic modification of commercially important crops for improvement of cold tolerance.
Asunto(s)
Proteínas Anticongelantes/genética , Respuesta al Choque por Frío/genética , Escherichia coli/genética , Fabaceae/genética , Nicotiana/genética , Adaptación Fisiológica/genética , Proteínas Anticongelantes/biosíntesis , Proteínas Anticongelantes/metabolismo , Frío/efectos adversos , Escherichia coli/citología , Escherichia coli/metabolismo , Fabaceae/metabolismo , Congelación , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Regiones Promotoras Genéticas , Nicotiana/citología , Nicotiana/metabolismo , Transformación GenéticaRESUMEN
A homologous sequence was amplified from resurrection plant Selaginella pulvinta by RACE technique, proved to be the full-length cDNA of trehalose-6-phosphate synthase gene by homologous alignment and yeast complementation assay, and nominated as SpTPS1 gene. The open reading frame of this gene was truncated 225bp at the 5'-end, resulting the N-terminal truncation modification of 75 amino acids for its encoding protein. The TPS1 deletion mutant strain YSH290 of the brewer's yeast transformed by the truncated gene SpTPS1Δ and its original full-length version restored growth on the medium with glucose as a sole carbon source and displayed growth curves with no significant difference, indicating their encoding proteins functioning as TPS enzyme. The TPS activity of the mutant strain transformed by the truncated gene SpTPS1Δ was about six fold higher than that transformed by its original version, reasoning that the extra N-terminal extension of the full-length amino acid sequence acts as an inhibitory domain to trehalose synthesis. However, the trehalose accumulation of the mutant strain transformed by the truncated gene SpTPS1Δ was only 8% higher than that transformed by its original version. This result is explained by the feedback balance of trehalose content coordinated by the comparative activities between trehalose synthase and trehalase. The truncated gene SpTPS1Δ is suggested to be used in transgenic operation, together with the inhibition of trehalase activity by the application of validamycin A or genetic deficiency of the endogenous trehalase gene, for the enhancement of trehalose accumulation and improvement of abiotic tolerance in transgenic plants.
Asunto(s)
Secuencia de Aminoácidos , Glucosiltransferasas/metabolismo , Proteínas de Plantas/metabolismo , Selaginellaceae/enzimología , Eliminación de Secuencia , Clonación Molecular , Prueba de Complementación Genética , Glucosiltransferasas/genética , Mutación , Sistemas de Lectura Abierta/fisiología , Proteínas de Plantas/genética , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genética , Selaginellaceae/genética , Trehalosa/genética , Trehalosa/metabolismoRESUMEN
The genetic transformation mediated by Agrobacterium tumefaciens has been widely applied to research of transgenic plants. As the vector of the exotic genes, the integration patterns of T-DNA fragments affects not only transformation efficiency and stability, but also expression properties of the transgenes. This review summaries the two major patterns and the rules of T-DNA integration in Agrobacterim-mediated transformation, rules of T-DNA mediated by Agrobacterium tumefaciens, as well as research tools for flanking sequence amplification. It is attempted to provide references for researches on transformation and T-DNA integration mutation mediated by Agrobacterium tumefaciens.
Asunto(s)
Agrobacterium tumefaciens/genética , ADN Bacteriano/genética , Plantas Modificadas Genéticamente/genética , Transformación Genética , Reacción en Cadena de la PolimerasaRESUMEN
To overcome the low efficiency of agronomic protection from maize dwarf mosaic disease, susceptible maize inbred line was transformed by Agrobacterium tumefaciens harboring hpRNA expression vectors containing inverted-repeat sequences of different lengths targeting coat protein gene (CP) of maize dwarf mosaic virus (MDMV). After PCR screening and Southern blotting, the flanking sequences of the integration sites were amplified by thermal asymmetric interlaced PCR (TAIL-PCR) and used for analysis of T-DNA integration patterns. The T2 plant lines were evaluated for their MDMV resistance in field inoculation trials under two environments. Of the nineteen T2 plant lines positive in Southern blotting, six were evaluated as resistant to MDMV, and four of them had resistance non-significantly different from the highly resistant control "H9-21", while the resistance of the other eleven was proved to be significantly improved when compared to their non-transformed parent line. These improvements in MDMV resistance were verified by the relative amount of virus CP gene expression measured by quantitative real time PCR. Comparing the results of Southern blotting and TAIL-PCR analysis, different integration patterns of one or two copies of the inverted-repeat sequences were identified from non-repetitive and repetitive sequences of the maize genome. The MDMV resistance mediated by RNA interference is relative to the length of the inverted-repeat sequence, the copy number of T-DNA integration and the repeatability of integration sites. A longer hpRNA expression construct shows more efficiency than a shorter one.
Asunto(s)
Virus del Mosaico/genética , Plantas Modificadas Genéticamente/genética , Interferencia de ARN , Zea mays/genética , Agrobacterium tumefaciens/genética , Secuencia de Bases , Proteínas de la Cápside/genética , Electroforesis en Gel de Agar , Ingeniería Genética , Inmunidad Innata , Secuencias Invertidas Repetidas , Datos de Secuencia Molecular , Virus del Mosaico/patogenicidad , Plantas Modificadas Genéticamente/fisiología , Plantas Modificadas Genéticamente/virología , Reacción en Cadena de la Polimerasa , Transformación Genética , Transgenes , Integración Viral , Zea mays/fisiología , Zea mays/virologíaRESUMEN
Trehalose-6-phosphate synthase, a key enzyme in trehalose synthesis pathway of plant, plays an important role in response to abiotic stress in xerophilous rock lily and other resurrection plants. In this study, homologous amplification and RACE technique were used to clone gene SpTPS1 for trehalose-6-phosphate synthase from Selaginella pulvinata, which is an endemic xerophilous plant in China. The full-length cDNA is 3223 bp long, containing an open reading frame (ORF) of 2790 bp. Protein sequence comparison showed that the pupative amino acid sequence of this ORF shares high similarity to trehalose-6-phosphate synthases of mode species, especially at the conserved sites of catalytic activity centers. Yeast functional complementation test showed that trehalose-6-phosphate synthase mutant (tps1 big up tri, open), transformed by the ORF of SpTPS1 gene, can restore growth on the medium supplemented with glucose as a sole carbon source. This result indicated that SpTPS1 of S. pulvinata encodes for an active protein and is hopeful to be applied in transgenic improvement of abiotic stress tolerance in plant.
Asunto(s)
Glucosiltransferasas/genética , Proteínas de Plantas/genética , Selaginellaceae/genética , Secuencia de Aminoácidos , Clonación Molecular , ADN Complementario/química , ADN Complementario/genética , Prueba de Complementación Genética , Glucosiltransferasas/metabolismo , Datos de Secuencia Molecular , Mutación , Sistemas de Lectura Abierta/genética , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crecimiento & desarrollo , Selaginellaceae/enzimología , Análisis de Secuencia de ADN , Homología de Secuencia de AminoácidoRESUMEN
The expression of imprinted genes is regulated by epigenetic mechanism. In plant endosperm, the allele of imprinted genes is expressed in a pattern of parent-of-origin-dependent. The expression of imprinted genes plays essential roles in the development of embryos and their annexe structures, as well as seed size, reproductive barriers and apomixis. Along with the progress of plant epigenetic research, the exploration of imprinted genes is becoming hotspot in epigenetic research. This review focused on the parental conflict theory about the origin of imprinted genes, and the latest research advances in expression regulation mechanism of plant imprinted genes, using the examples of the important imprinted genes MEA, FIS2, FWA, MPC, and PHE1 in Arabidopsis, and FIEI and FIE2 in maize.
Asunto(s)
Genes de Plantas/genética , Impresión Genómica/genética , Plantas/genética , AnimalesRESUMEN
MicroRNAs (miRNAs) are an extensive class of tiny RNA molecules that regulate the expression of target genes by means of complementary base pair interactions. Identification of miRNAs and their target genes is essential to understand the regulation network of miRNAs in gene expression. With the method of bioinformatic computation, we used previously deposited miRNA sequences from Arabidopsis, rice, and other plant species to blast the databases of maize expressed sequence tags and genomic survey sequence that do not correspond to protein coding genes. A total of 11 novel miRNAs were identified from maize following a range of filtering criteria. All the potential miRNA precursors can be folded into the typical secondary structure of miRNA family, despite of variation in length and structure. Using these miRNAs sequences, we further blasted the databases of maize mRNAs and identified 26 target genes for seven of the eleven newly identified miRNAs. These genes encode twenty-six proteins involved in metabolism, signal transduction, transcriptional regulation, transmembrane transport, biostress, and abiostress responses, as well as chloroplast assembly. The identification of these novel miRNAs is a useful complement to the maize miRNA database.
Asunto(s)
Biología Computacional , MicroARNs/genética , Zea mays/genética , Secuencia de Bases , Datos de Secuencia Molecular , Conformación de Ácido NucleicoRESUMEN
To provide a useful piece of information for the choice of molecular markers to be used in selection of drought tolerance, mRNA differential display was used to isolate genes from a drought-tolerant maize inbred line '81565'. After drought stress, two down-regulated expression gene fragments (MD1 and MD2) and one up-regulated expression fragment (MD3) were obtained. Results of sequence and homology analysis show that MD1 has 97% similarity with matK in maize chloroplast genome, a gene encoding RNA maturase involved in group II intron splicing of RNA transcript; MD2 has 99% similarity with the gene serine/threonine phosphorylase 2C in Sporobolus stapfianus; and MD3 has 99% similarity with rice the gene encoding metacaspase, an arginine/lysine-specific cysteine protease. Based on the sequence of fragment MD2, a new member of maize PP2C gene family, ZmPP2Ca, was cloned by in silicon cloning and reverse transcription polymerase chain reaction (RT-PCR). Real-time fluorescence quantitative polymerase chain reaction (FQ-PCR) showed that expression of the gene was down-regulated in the three drought-tolerant lines ('81565', 'N87-1' and 'R09') and up-regulated in the two drought-sensitive lines ('200B' and 'ES40') under drought stress.