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Amino acid transporters (AATs) are integral membrane proteins and play important roles in plant growth and development as well as environmental responses. In contrast to the amino acid permease (AAP) subfamily, functional studies of the lysine and histidine transporter (LHT) subfamily have not been made in rice. In the current study, six LHT genes were found in the rice genome. To further investigate the functions of these genes, analyses were performed regarding gene and protein structures, chromosomal locations, evolutionary relationships, cis-acting elements of promoters, gene expression, and yeast complementation. We found that the six OsLHT genes are distributed on 4 out of the 12 chromosomes and that the six OsLHT genes were grouped into two clusters based on the phylogenetic analysis. Protein structure analyses showed that each OsLHT protein has 11 helical transmembrane domains. Yeast complementation assays showed that these OsLHT genes have conserved transport substrates within each cluster. The four members from cluster 1 showed broad amino acid selectivity, while OsLHT5 and OsLHT6 may transport other substrates besides amino acids. Additionally, quantitative real-time PCR analysis of the six OsLHT genes revealed that they have different expression patterns at different developmental stages and in different tissues. It also revealed that some OsLHT genes were responsive to PEG, NaCl and cold treatments, indicating their critical roles in abiotic stress response. Our results will be useful for further characterizing the crucial biological functions of rice LHT genes.
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IQM, a plant-specific calmodulin-binding protein, plays multiple roles in plant growth and development. Although a comprehensive analysis has been carried out on the IQM family genes in Arabidopsis and rice, the number and functions of IQM genes in other species have not been explored. In this study, we identified 15 members of the soybean (Glycine max) IQM gene family using BLASTP tools. These members were distributed on 12 soybean chromosomes and constitute six pairs caused by fragment duplication events. According to phylogeny, the 15 genes were divided into three subfamilies (I, II, and III), and members of the same subfamily had similar gene and protein structures. Yeast two-hybrid experiments revealed that the IQ motif is critical for the binding of GmIQM proteins to GmCaM, and its function is conserved in soybean, Arabidopsis, and rice. Based on real-time PCR, the soybean IQM genes were strongly induced by PEG and NaCl, suggesting their important biological functions in abiotic stress responses. Overall, this genome-wide analysis of the soybean IQM gene family lays a solid theoretical foundation for further research on the functions of GmIQM genes and could serve as a reference for the improvement and breeding of soybean stress resistance traits.
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Members of the IQM (IQ-Motif Containing) gene family are involved in plant growth and developmental processes, biotic and abiotic stress response. To systematically analyze the IQM gene family and their expression profiles under diverse biotic and abiotic stresses, we identified 8 IQM genes in the rice genome. In the current study, the whole genome identification and characterization of OsIQMs, including the gene and protein structure, genome localization, phylogenetic relationship, gene expression and yeast two-hybrid were performed. Eight IQM genes were classified into three subfamilies (I-III) according to the phylogenetic analysis. Gene structure and protein motif analyses showed that these IQM genes are relatively conserved within each subfamily of rice. The 8 OsIQM genes are distributed on seven out of the twelve chromosomes, with three IQM gene pairs involved in segmental duplication events. The evolutionary patterns analysis revealed that the IQM genes underwent a large-scale event within the last 20 to 9 million years. In addition, quantitative real-time PCR analysis of eight OsIQMs genes displayed different expression patterns at different developmental stages and in different tissues as well as showed that most IQM genes were responsive to PEG, NaCl, jasmonic acid (JA), abscisic acid (ABA) treatment, suggesting their crucial roles in biotic, and abiotic stress response. Additionally, a yeast two-hybrid assay showed that OsIQMs can interact with OsCaMs, and the IQ motif of OsIQMs is required for OsIQMs to combine with OsCaMs. Our results will be valuable to further characterize the important biological functions of rice IQM genes.
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Enhancing nitrogen (N) use efficiency is a potential way to reduce excessive nitrogen application and increase yield. Autophagy is a conserved degradation system in the evolution of eukaryotic cells and plays an important role in plant development and stress response. Autophagic cores have two conjugation pathways that attach the product of autophagy-related gene 8 (ATG8) to phosphatidylethanolamine (PE) and ATG5 to ATG12, respectively, which then help with vesicle elongation and enclosure. Rice has six ATG8 genes, which have not been functionally confirmed so far. We identified the rice gene OsATG8b and characterized its role in N remobilization to affect grain quality by generating transgenic plants with its over-expression and knockdown. Our study confirmed the autophagy activity of OsATG8b through the complementation of the yeast autophagy-defective mutant scatg8 and by observation of autophagosome formation in rice. The autophagy activity is higher in OsATG8b-OE lines and lower in OsATG8b-RNAi than that in wild type (ZH11). 15N pulse-chase analysis revealed that OsATG8b-OE plants conferred higher N recycling efficiency to grains, while OsATG8b-RNAi transgenic plants exhibited lower N recycling efficiency and poorer grain quality. The autophagic role of OsATG8b was experimentally confirmed, and it was concluded that OsATG8b-mediated autophagy is involved in N recycling to grains and contributes to the grain quality, indicating that OsATG8b may be a potential gene for molecular breeding and cultivation of rice.
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Adaptive changes in plant phenology are often considered to be a feature of the so-called 'domestication syndrome' that distinguishes modern crops from their wild progenitors, but little detailed evidence supports this idea. In soybean, a major legume crop, flowering time variation is well characterized within domesticated germplasm and is critical for modern production, but its importance during domestication is unclear. Here, we identify sequential contributions of two homeologous pseudo-response-regulator genes, Tof12 and Tof11, to ancient flowering time adaptation, and demonstrate that they act via LHY homologs to promote expression of the legume-specific E1 gene and delay flowering under long photoperiods. We show that Tof12-dependent acceleration of maturity accompanied a reduction in dormancy and seed dispersal during soybean domestication, possibly predisposing the incipient crop to latitudinal expansion. Better understanding of this early phase of crop evolution will help to identify functional variation lost during domestication and exploit its potential for future crop improvement.
Assuntos
Produtos Agrícolas/genética , Flores/genética , Genes de Plantas/genética , Glycine max/genética , Domesticação , Fabaceae/genética , Fotoperíodo , Sementes/genéticaRESUMO
Calmodulin (CaM) regulates plant disease responses through its downstream calmodulin-binding proteins (CaMBPs) often by affecting the biosynthesis or signaling of phytohormones, such as jasmonic acid (JA) and salicylic acid. However, how these CaMBPs mediate plant hormones and other stress resistance-related signaling remains largely unknown. In this study, we conducted analyses in Arabidopsis (Arabidopsis thaliana) on the functions of AtIQM1 (IQ-Motif Containing Protein1), a Ca2+-independent CaMBP, in JA biosynthesis and defense against the necrotrophic pathogen Botrytis cinerea using molecular, biochemical, and genetic analyses. IQM1 directly interacted with and promoted CATALASE2 (CAT2) expression and CAT2 enzyme activity and indirectly increased the activity of the JA biosynthetic enzymes ACX2 and ACX3 through CAT2, thereby positively regulating JA content and B. cinerea resistance. In addition, in vitro assays showed that in the presence of CaM5, IQM1 further enhanced the activity of CAT2, suggesting that CaM5 may affect the activity of CAT2 by combining with IQM1 in the absence of Ca2+ Our data indicate that IQM1 is a key regulatory factor in signaling of plant disease responses mediated by JA. The study also provides new insights that CaMBP may play a critical role in the cross talk of multiple signaling pathways in the context of plant defense processes.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Botrytis/fisiologia , Proteínas de Ligação a Calmodulina/metabolismo , Doenças das Plantas/imunologia , Reguladores de Crescimento de Plantas/metabolismo , Motivos de Aminoácidos , Arabidopsis/enzimologia , Arabidopsis/imunologia , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Sinalização do Cálcio , Proteínas de Ligação a Calmodulina/genética , Ciclopentanos/metabolismo , Resistência à Doença , Oxilipinas/metabolismo , Doenças das Plantas/microbiologia , Estômatos de Plantas/enzimologia , Estômatos de Plantas/genética , Estômatos de Plantas/imunologia , Estômatos de Plantas/microbiologia , Ácido Salicílico/metabolismoRESUMO
Seed dormancy and germination are regulated by complex mechanisms controlled by diverse hormones and environmental cues. Abscisic acid (ABA) promotes seed dormancy and inhibits seed germination and post-germination growth. Calmodulin (CaM) signals are involved with the inhibition of ABA during seed germination and seedling growth. In this study, we showed that Arabidopsis thaliana IQM4 could bind with calmodulin 5 (CaM5) both in vitro and in vivo, and that the interaction was the Ca2+-independent type. The IQM4 protein was localized in the chloroplast and the IQM4 gene was expressed in most tissues, especially the embryo and germinated seedlings. The T-DNA insertion mutants of IQM4 exhibited the reduced primary seed dormancy and lower ABA levels compared with wild type seeds. Moreover, IQM4 plays key roles in modulating the responses to ABA, salt, and osmotic stress during seed germination and post-germination growth. T-DNA insertion mutants exhibited ABA-insensitive and salt-hypersensitive phenotypes during seed germination and post-germination growth, whereas IQM4-overexpressing lines had ABA- and osmotic-hypersensitive, and salt-insensitive phenotypes. Gene expression analyses showed that mutation of IQM4 inhibited the expression of ABA biosynthetic genes NCED6 and NCED9, and seed maturation regulators LEC1, LEC2, ABI3, and ABI5 during the silique development, as well as promoted the expression of WRKY40 and inhibited that of ABI5 in ABA-regulated seed germination. These observations suggest that IQM4 is a novel Ca2+-independent CaM-binding protein, which is positively involved with seed dormancy and germination in Arabidopsis.
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Natural and synthetic progestins may pose a threat to wild fish populations living in receiving waters. In this study, the effects of norethindrone (NET) on the sex differentiation of zebrafish (Dario renio) and the mechanisms underlying these effects were investigated. Juvenile zebrafish (20 days post fertilization, pdf) were exposed to environmentally relevant concentrations (5, 50, 500, and 1000 ng L-1) for 45 d. Sex ratio of the NET-exposed populations, the histology of the gonads and the transcriptional profile of the regulatory genes involved in sex differentiation and steroidogenesis were examined. The results showed that a significantly higher ratio of male/female was induced in the zebrafish populations exposed to NET at concentrations higher than 32.3 ng L-1. Exposure to NET caused acceleration of sexual mature in males and a delay in ovary maturation in female zebrafish. Among the genes regulating sexual differentiation, transcripts of Dmrt1 showed a dose-dependent increase while transcripts of Figa and Fox12 showed a dose-dependent decrease in response to exposure to NET. For genes regulating the steroidogenesis, the expressions of Cyp11a1, Cyp17, Cyp19a1a, and Cyp11b were significantly down-regulated by exposure to NET, while Hsd17b3 expression was significantly up-regulated by exposure to NET at 421.3 and 892.9 ng L-1. For the receptor genes in the gonads, the transcriptional expression of Pgr, Ar, and Mr was significantly up-regulated at 421.3 and 892.9 ng L-1 of NET. For genes involved in the hypothalamic-pituitary axis, the transcriptional expression of Gnrh3 and Pomc was significantly up-regulated by exposure to NET with the exception for Gnrh3 at 4.2 ng L-1. The results demonstrated that exposure to NET at the juvenile stage could affect gonad differentiation and sex ratio, which might be accounted for by the alterations of the transcriptional expressions of genes along the hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-adrenal (HPA) axes.
Assuntos
Perfilação da Expressão Gênica , Sistema Hipotálamo-Hipofisário/metabolismo , Noretindrona/farmacologia , Sistema Hipófise-Suprarrenal/metabolismo , Progestinas/farmacologia , Diferenciação Sexual/genética , Peixe-Zebra/genética , Animais , Feminino , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Células Germinativas/efeitos dos fármacos , Células Germinativas/metabolismo , Gônadas/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Masculino , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Diferenciação Sexual/efeitos dos fármacos , Razão de Masculinidade , Maturidade Sexual , Poluentes Químicos da Água/toxicidadeRESUMO
This study aimed to determine the effects of Androstenodione (AED) on the transcriptional expression of genes involved in the hypothalamic-pituitary-gonadal (HPG) and the hypothalamic-pituitary-adrenal (HPA) axes in the zebrafish embryos/larvae. Zebrafish embryos were exposed to 0, 4.0, 45.0, 487.0, and 980.0â¯ng/L of AED from the day of fertilization to 144â¯h post fertilization (hpf), during which the transcriptional profiles of key genes related to the HPG and HPA axes were examined daily using quantitative real-time PCR. The AED exposure significantly up-regulated several receptor signaling pathways and the key genes involved in various steps of the steroidogenic pathways were also affected. In addition, the AED exposure could significantly modulate the transcriptional profiles of the other target genes related to hypothalamic and pituitary hormones. The findings of this study suggest that AED, at environmentally relevant concentrations, affects the adrenal endocrine systems and the reproduction of zebrafish by interrupting the HPG and HPA axes.
Assuntos
Androstenodiona/farmacologia , Gônadas/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Larva/efeitos dos fármacos , Hipófise/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Animais , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Sistema Endócrino/efeitos dos fármacos , Regulação da Expressão Gênica , Gônadas/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Hipófise/metabolismo , Sistema Hipófise-Suprarrenal/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodução/efeitos dos fármacos , Transcrição Gênica , Peixe-Zebra/embriologiaRESUMO
Synthetic hormones in wastewater effluents released into the aquatic environments may interfere with the normal endocrine systems of fish in receiving streams. Norgestrel (NGT) is a synthetic progestin widely used in oral contraceptives and frequently detected in wastewater effluents. In this study, adult female mosquitofish (Gambusia affinis) were exposed to three environmentally relevant concentrations of norgestrel (NGT) (i.e., 3.6, 35.8, and 368.0â¯ngâ¯L-1) for 42â¯d, fin morphology, histology of the ovary, and reproductive behaviors were evaluated. The results showed that NGT at all three concentrations caused an increased frequency of atretic follicular cells in ovaries and impaired mating behaviors exhibited by males toward the NGT-exposed females. In mosquitofish exposed to NGT at 35.8 and 368â¯ngâ¯L-1, the anal fin of females had an increased length ratio of ray4/ray 6, an increased width of ray 3, and increased number of segments in ray 3. The histopathological analysis showed that exposure to NGT increased the incidence of spermatogenesis in ovaries. Mating behavior was impaired 58.4%, 65.7%, and 76.4% (Pâ¯<â¯0.01 in all cases) when mosquitofish were exposed to NGT at 3.6, 35.6 and 368.0â¯ngâ¯L-1, respectively. The rapid masculinization, the increased frequency of atretic follicles, the incidence of spermatogenesis in the ovary of female fish, and the altered reproductive behaviors suggest that wild populations of mosquitofish could be similarly affected inhabiting in NGT contaminated environments.
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Comportamento Animal/efeitos dos fármacos , Ciprinodontiformes/fisiologia , Norgestrel/toxicidade , Reprodução/efeitos dos fármacos , Caracteres Sexuais , Nadadeiras de Animais/anatomia & histologia , Nadadeiras de Animais/efeitos dos fármacos , Animais , Exposição Ambiental/análise , Feminino , Masculino , Oócitos/citologia , Oócitos/efeitos dos fármacos , Ovário/química , Ovário/efeitos dos fármacos , Poluentes Químicos da Água/toxicidadeRESUMO
The transition from vegetative to reproductive growth phase is a pivotal and complicated process in the life cycle of flowering plants which requires a comprehensive response to multiple environmental aspects and endogenous signals. In Arabidopsis, six regulatory flowering time pathways have been defined by their response to distinct cues, namely photoperiod, vernalization, gibberellin, temperature, autonomous and age pathways, respectively. Among these pathways, the autonomous flowering pathway accelerates flowering independently of day length by inhibiting the central flowering repressor FLC. FCA, FLD, FLK, FPA, FVE, FY and LD have been widely known to play crucial roles in this pathway. Recently, AGL28, CK2, DBP1, DRM1, DRM2, ESD4, HDA5, HDA6, PCFS4, PEP, PP2A-B'γ, PRMT5, PRMT10, PRP39-1, REF6, and SYP22 have also been shown to be involved in the autonomous flowering time pathway. This review mainly focuses on FLC RNA processing, chromatin modification of FLC, post-translational modification of FLC and other molecular mechanisms in the autonomous flowering pathway of Arabidopsis.
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Polygalacturonase is one of the pectin hydrolytic enzymes involved in various developmental and physiological processes such as seed germination, organ abscission, pod and anther dehiscence, and xylem cell formation. To date, no systematic analysis of polygalacturonase incorporating genome organization, gene structure, and expression profiling has been conducted in soybean (Glycine max var. Williams 82). In this study, we identified 112 GmPG genes from the soybean Wm82.a2v1 genome. These genes were classified into three groups, group I (105 genes), group II (5 genes), and group III (2 genes). Fifty-four pairs of duplicate paralogous genes were preferentially identified from duplicated regions of the soybean genome, which implied that long segmental duplications significantly contributed to the expansion of the GmPG gene family. Moreover, GmPG transcripts were analyzed in various tissues using RNA-seq data. The results showed the differential expression of 64 GmPGs in the tissue and partially redundant expression of some duplicate genes, while others showed functional diversity. These findings suggested that the GmPGs were retained by substantial subfunctionalization during the soybean evolutionary processes. Finally, evolutionary analysis based on single nucleotide polymorphisms (SNPs) in wild and cultivated soybeans revealed that 107 GmPGs had selected site(s), which indicated that these genes may have undergone strong selection during soybean domestication. Among them, one non-synonymous SNP of GmPG031 affected floral development during selection, which was consistent with the results of RNA-seq and evolutionary analyses. Thus, our results contribute to the functional characterization of GmPG genes in soybean.
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In this study, the Agrobacterium tumefaciens-mediated transformation method for Ganderma weberianum has been established. Driven by the cauliflower mosaic virus (CaMV) 35S promoter, the hygromycin phosphotransferase (hpt), ß-glucuronidase (uidA), and enhanced green fluorescent protein (egfp) genes have been efficiently expressed in transgenic mycelia and spores. The transformation system was composed of the growing mycelia, A. tumefaciens strain GV3101, and the expression vector pBI-H1, harboring the CaMV 35S promoter and selective hpt marker. The genetic transformation of G. weberianum was achieved through co-cultivation of Agrobacterium lawn and fungal mycelia at 28 °C on yeast extract agar (YEA) medium. Stable genetic transformants were obtained through successive hygromycin B selections and single spore isolation. Over 80 % of transformants showed genetic stability even after ten rounds of subculturing. The simple and efficient genetic transformation method is a useful tool for molecular genetics analyses and gene manipulation of G. weberianum.
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Ganoderma/genética , Técnicas Genéticas , Transformação Genética , Agrobacterium tumefaciens/genética , Agrobacterium tumefaciens/metabolismo , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Proteínas de Fluorescência VerdeRESUMO
BACKGROUND: Cymbidium sinense belongs to the Orchidaceae, which is one of the most abundant angiosperm families. C. sinense, a high-grade traditional potted flower, is most prevalent in China and some Southeast Asian countries. The control of flowering time is a major bottleneck in the industrialized development of C. sinense. Little is known about the mechanisms responsible for floral development in this orchid. Moreover, genome references for entire transcriptome sequences do not currently exist for C. sinense. Thus, transcriptome and expression profiling data for this species are needed as an important resource to identify genes and to better understand the biological mechanisms of floral development in C. sinense. RESULTS: In this study, de novo transcriptome assembly and gene expression analysis using Illumina sequencing technology were performed. Transcriptome analysis assembles gene-related information related to vegetative and reproductive growth of C. sinense. Illumina sequencing generated 54,248,006 high quality reads that were assembled into 83,580 unigenes with an average sequence length of 612 base pairs, including 13,315 clusters and 70,265 singletons. A total of 41,687 (49.88%) unique sequences were annotated, 23,092 of which were assigned to specific metabolic pathways by the Kyoto Encyclopedia of Genes and Genomes (KEGG). Gene Ontology (GO) analysis of the annotated unigenes revealed that the majority of sequenced genes were associated with metabolic and cellular processes, cell and cell parts, catalytic activity and binding. Furthermore, 120 flowering-associated unigenes, 73 MADS-box unigenes and 28 CONSTANS-LIKE (COL) unigenes were identified from our collection. In addition, three digital gene expression (DGE) libraries were constructed for the vegetative phase (VP), floral differentiation phase (FDP) and reproductive phase (RP). The specific expression of many genes in the three development phases was also identified. 32 genes among three sub-libraries with high differential expression were selected as candidates connected with flower development. CONCLUSION: RNA-seq and DGE profiling data provided comprehensive gene expression information at the transcriptional level that could facilitate our understanding of the molecular mechanisms of floral development at three development phases of C. sinense. This data could be used as an important resource for investigating the genetics of the flowering pathway and various biological mechanisms in this orchid.
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Flores/genética , Orchidaceae/genética , Transcriptoma , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Redes e Vias Metabólicas/genética , Orchidaceae/crescimento & desenvolvimento , FilogeniaRESUMO
We recently identified a novel IQ motif-containing protein family, IQM, which shares sequence homology with a pea heavy metal-induced protein 6 and a ribosome inactivating protein, trichosanthin. Distinct expression patterns for each gene suggest that each IQM family member may play a different role in plant development and response to environmental cues. However functions of the IQM family members remain to be analyzed. IQM1 bound with calmodulin 5 (CaM5) in yeast two-hybrid assay via its IQ-motif. The CaM binding was Ca(2+)-independent in vitro, and was also observed in bimolecular fluorescence complementation analyses in onion epidermal cells. IQM1 was found to express strongly in guard cells and the cortex of roots. The T-DNA insertion mutants of IQM1 displayed a smaller stomatal aperture, a decreased water loss rate and a shorter primary root. Moreover, iqm1 did not change its stomatal aperture when treated with light, dark, ABA and chitin obviously. Microarray analyses showed that 243 and 28 genes were up- and down-regulated by more than twofold in iqm1-1, respectively. Interesting, 34 of 117 and 7 of 30 chitin-responsive transcriptional factor and ubiquitin ligase genes were up-regulated, respectively. Stomatal guard cells of iqm1-1 also showed enhanced expression of genes involved in production and signaling of reactive oxygen species (ROS). Consistently, increased ROS level was observed in the iqm1 guard cells.
Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/fisiologia , Proteínas de Ligação a Calmodulina/fisiologia , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Sinalização do Cálcio , Proteínas de Ligação a Calmodulina/química , Proteínas de Ligação a Calmodulina/genética , Quitina/metabolismo , DNA Bacteriano/genética , Fungos/patogenicidade , Perfilação da Expressão Gênica , Genes de Plantas , Movimento/fisiologia , Mutagênese Insercional , Estômatos de Plantas/genética , Estômatos de Plantas/fisiologia , Domínios e Motivos de Interação entre Proteínas , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Técnicas do Sistema de Duplo-HíbridoRESUMO
The microRNA miR393 has been shown to play a role in plant development and in the stress response by targeting mRNAs that code for the auxin receptors in Arabidopsis. In this study, we verified that two rice auxin receptor gene homologs (OsTIR1 and OsAFB2) could be targeted by OsmiR393 (Os for Oryza sativa). Two new phenotypes (increased tillers and early flowering) and two previously observed phenotypes (reduced tolerance to salt and drought and hyposensitivity to auxin) were observed in the OsmiR393-overexpressing rice plants. The OsmiR393-overexpressing rice demonstrated hyposensitivity to synthetic auxin-analog treatments. These data indicated that the phenotypes of OsmiR393-overexpressing rice may be caused through hyposensitivity to the auxin signal by reduced expression of two auxin receptor genes (OsTIR1 and OsAFB2). The expression of an auxin transporter (OsAUX1) and a tillering inhibitor (OsTB1) were downregulated by overexpression of OsmiR393, which suggested that a gene chain from OsmiR393 to rice tillering may be from OsTIR1 and OsAFB2 to OsAUX1, which affected the transportation of auxin, then to OsTB1, which finally controlled tillering. The positive phenotypes (increased tillers and early flowering) and negative phenotypes (reduced tolerance to salt and hyposensitivity to auxin) of OsmiR393-overexpressing rice present a dilemma for molecular breeding.
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Regulação para Baixo/genética , Secas , Flores/fisiologia , MicroRNAs/genética , Oryza/genética , Proteínas de Plantas/genética , Cloreto de Sódio/farmacologia , Ácido 2,4-Diclorofenoxiacético/farmacologia , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/genética , Regulação para Baixo/efeitos dos fármacos , Flores/efeitos dos fármacos , Flores/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas/genética , Ácidos Indolacéticos/metabolismo , MicroRNAs/metabolismo , Modelos Biológicos , Ácidos Naftalenoacéticos/farmacologia , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/genética , Oryza/efeitos dos fármacos , Oryza/fisiologia , Fenótipo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Reprodutibilidade dos Testes , Homologia de Sequência do Ácido Nucleico , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fatores de TempoRESUMO
Three 5,5'-azotetrazolate based Zn(II) and Ni(II) complexes exhibit novel supramolecular structures and emit multi-photoluminescence under laser excitation and the multi-photoluminescence promises a multi-channel signal photoluminescent material.
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Complexos de Coordenação/química , Níquel/química , Zidovudina/química , Zinco/química , Complexos de Coordenação/síntese química , Cristalografia por Raios X , Microscopia Confocal , Microscopia de Fluorescência , Conformação Molecular , Zidovudina/síntese químicaRESUMO
Two mutations in Arabidopsis thaliana, auxin response factor6 (arf6) and arf8, concomitantly delayed the elongation of floral organs and subsequently delayed the opening of flower buds. This phenotype is shared with the jasmonic acid (JA)-deficient mutant dad1, and, indeed, the JA level of arf6 arf8 flower buds was decreased. Among JA biosynthetic genes, the expression level of DAD1 (DEFECTIVE IN ANTHER DEHISCENCE1) was markedly decreased in the double mutant, suggesting that ARF6 and ARF8 are required for activation of DAD1 expression. The double mutant arf6 arf8 also showed other developmental defects in flowers, such as aberrant vascular patterning and lack of epidermal cell differentiation in petals. We found that class 1 KNOX genes were expressed ectopically in the developing floral organs of arf6 arf8, and mutations in any of the class 1 KNOX genes (knat2, knat6, bp and hemizygous stm) partially suppressed the defects in the double mutant. Furthermore, ectopic expression of the STM gene caused a phenotype similar to that of arf6 arf8, including the down-regulation of DAD1 expression. These results suggested that most defects in arf6 arf8 are attributable to abnormal expression of class 1 KNOX genes. The expression of AS1 and AS2 was not affected in arf6 arf8 flowers, and as1 and arf6 arf8 additively increased the expression of class 1 KNOX genes. We concluded that ARF6 and ARF8, in parallel with AS1 and AS2, repress the class 1 KNOX genes in developing floral organs to allow progression of the development of these organs.
Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Ciclopentanos/metabolismo , Proteínas de Ligação a DNA/genética , Flores/genética , Proteínas de Homeodomínio/genética , Oxilipinas/metabolismo , Fatores de Transcrição/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Padronização Corporal/genética , Diferenciação Celular/genética , Proteínas de Ligação a DNA/metabolismo , Flores/crescimento & desenvolvimento , Flores/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Homeodomínio/metabolismo , Mutação/genética , Fenótipo , Fosfolipases A1/genética , Fosfolipases A1/metabolismo , Epiderme Vegetal/genética , Epiderme Vegetal/crescimento & desenvolvimento , Epiderme Vegetal/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismoRESUMO
A new method for the determination of the total volatile basic nitrogen (TVB-N) by reflectance spectroscopy was developed. The method was based on the reaction of TVB-N with Nessler's reagent treated by molecular sieve and the reflectance-absorption value F(R), which is directly proportional to the amount of NH2 Hg IO in solid phase, was measured by the reflection spectrometer. The fundamental principle, effective factors and experimental conditions of the method were discussed. The special features of this method were its simplicity in operation, relatively high sensitivity of determination and the use of a small amount of reagent. Linear calibration graph was obtained in the range 1-8 microg x mL(-1) with a detection limit of 0.1 microg x mL(-1). The method was applied to monitor the fresh degree of fish and pork. The result discovered that the total volatile basic nitrogen increased rapidly along with the time extension, indicating that the deterioration of fish and pork was an acceleration process, and the deterioration speed of fish was faster than that of pork.
RESUMO
We investigated the physiological and molecular basis of lower fecundity of massugu2 (msg2), which is a dominant mutant of an auxin primary response gene, IAA19, in Arabidopsis thaliana. By measuring the length of all stamens and pistils in inflorescences and the reference growth rate of pistils, we constructed growth curves of pistils and stamens between stages 12 and 15 of flower development. Pistil growth was found to consist of a single exponential growth, while stamen growth consisted of three exponential phases. During the second exponential phase, the growth rate of stamen filaments was approximately 10 times greater than the growth rates in the other two phases. Consequently, stamens whose growth was initially retarded grew longer than the pistil, putting pollen grains on the stigma. msg2-1 stamens, on the other hand, exhibited a less obvious growth increase, resulting in less frequent contact between anthers and stigma. MSG2 was expressed in the stamen filaments and its expression almost coincided with the second growth phase. Stamen filaments appeared to elongate by cell elongation rather than cell division in the epidermal cell file. Considering that MSG2 is likely to be a direct target of the auxin F-box receptors, MSG2 may be one of the master genes that control the transient growth increase of stamen filaments.