RESUMO
It is extremely rare that a single virus crosses host barriers across multiple kingdoms. Based on phylogenetic and paleovirological analyses, it has previously been hypothesized that single members of the family Partitiviridae could cross multiple kingdoms. Partitiviridae accommodates members characterized by their simple bisegmented double-stranded RNA genome; asymptomatic infections of host organisms; the absence of an extracellular route for entry in nature; and collectively broad host range. Herein, we show the replicability of single fungal partitiviruses in three kingdoms of host organisms: Fungi, Plantae, and Animalia. Betapartitiviruses of the phytopathogenic fungusRosellinia necatrix could replicate in protoplasts of the carrot (Daucus carota), Nicotiana benthamiana and Nicotiana tabacum, in some cases reaching a level detectable by agarose gel electrophoresis. Moreover, betapartitiviruses showed more robust replication than the tested alphapartitiviruses. One of the fungal betapartitiviruses, RnPV18, could persistently and stably infect carrot plants regenerated from virion-transfected protoplasts. Both alpha- and betapartitiviruses, although with different host preference, could replicate in two insect cell lines derived from the fall armyworm Spodoptera frugiperda and the fruit fly Drosophila melanogaster. Our results indicate the replicability of single partitiviruses in members of three kingdoms and provide insights into virus adaptation, host jumping, and evolution.
Assuntos
Daucus carota , Nicotiana , Replicação Viral , Animais , Nicotiana/virologia , Nicotiana/microbiologia , Daucus carota/virologia , Daucus carota/microbiologia , Vírus de RNA/genética , Vírus de RNA/fisiologia , Micovírus/genética , Micovírus/classificação , Micovírus/fisiologia , Filogenia , Protoplastos/virologia , Doenças das Plantas/virologia , Doenças das Plantas/microbiologia , Spodoptera/virologia , Spodoptera/microbiologiaRESUMO
Percutaneous coronary intervention (PCI) for calcified lesions is one of the most challenging procedures related to worse clinical outcomes. To stabilize vulnerable plaques, intensive lipid management is recommended; however, the serial changes of calcified plaques under intensive lipid management are unknown. A total of 31 patients (mean age, 63 ± 10 years; men, 29 patients) who underwent PCI with intensive lipid management were retrospectively studied. We evaluated the serial longitudinal changes of calcified plaques with clear outer borders using optical coherence tomography (OCT) at two time points: at the time of PCI (baseline) and the chronic phase. The median interval from PCI to chronic phase was 287 (233-429) days. Twenty-eight patients (90.3%) had increased calcium volume at the chronic phase compared with those at baseline (2.6 [1.3-5.1] vs. 1.8 [0.7-4.3] mm2, p < 0.05), and the median increase rate of calcium volume was 27.4% at the chronic phase. According to the median increase rate of calcium volume (27.4%), patients were divided into the following two groups: rapid progression (≥ 27.4%, RP group) and non-rapid progression (< 27.4%, non-RP group). The RP group had more patients with diabetes, and diabetes was independently associated with rapid progression by multivariate analysis. Furthermore, patients with diabetes had significantly higher changes in calcium index and volume from the baseline to the chronic phase than those without diabetes. Coronary calcification progression during relatively short intervals was observed using OCT even under intensive lipid management. Diabetes was an independent predictor for rapid coronary calcification progression.
Assuntos
Doença da Artéria Coronariana , Diabetes Mellitus , Intervenção Coronária Percutânea , Placa Aterosclerótica , Calcificação Vascular , Masculino , Humanos , Pessoa de Meia-Idade , Idoso , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/terapia , Tomografia de Coerência Óptica/métodos , Estudos Retrospectivos , Cálcio , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/patologia , Placa Aterosclerótica/patologia , Lipídeos , Angiografia Coronária/métodos , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/terapiaRESUMO
BACKGROUND: The characteristics and clinical outcomes associated with sustained ventricular tachycardia and fibrillation (VT/VF) in Japanese acute myocardial infarction (AMI) patients remain unknown.MethodsâandâResults: Consecutive AMI patients (n=1,941) transferred to the Hirosaki University Hospital and treated with primary percutaneous coronary intervention (PCI) within 12 h of onset were retrospectively studied. The incidence of VT/VF during hospitalization was 8.3%, and 75% of cases occurred by the end of PCI. Independent predictors associated with VT/VF occurrence by the end of PCI and after PCI, respectively, were identified. Additionally, the differences between patients with VT and VF were examined, which revealed that the characteristics of patients and predictors for VT and VF were clearly different. Additionally, the QRS duration during VT was measured, which demonstrated the possible involvement of Purkinje fibers for VT in the acute phase of AMI. Of the patients with VT/VF, 12% required ECMO support due to refractory VT/VF despite intravenous antiarrhythmic agents such as ß-blockers, amiodarone, and nifekalant. Among the patients discharged alive, 1,690 were followed up for a mean of 3.7 years. VT/VF occurrence during hospitalization did not affect the mid-term clinical outcomes even in patients with VT. CONCLUSIONS: The results clearly indicated that VT/VF is still a serious complications of AMI. We need to identify patients at high risk of developing VT/VF for careful observation and appropriate intervention.
RESUMO
BACKGROUND: The incidence of sudden cardiac death (SCD) after discharge in Japanese acute myocardial infarction (AMI) patients with reduced left ventricular ejection fraction (LVEF) treated with primary percutaneous coronary intervention (PCI) remains unknown.MethodsâandâResults:The study population included 1,429 AMI patients (199 with LVEF ≤35% and 1,230 with LVEF >35%) admitted to the Hirosaki University Hospital, treated with primary PCI within 12 h after onset, and survived to discharge. LVEF was evaluated in all patients before discharge, and the patients were followed up for a mean of 2.6±0.8 years. The Kaplan-Meier survival curves revealed LVEF ≤35% was associated with all-cause death and SCD. The incidence of SCD was 2.6% at 1 year and 3.1% at 3 years in patients with LVEF ≤35%, whereas it was 0.1% at 1 year and 0.3% at 3 years in patients with LVEF >35%. Sixty-seven percent of SCDs in patients with LVEF ≤35% occurred within 4 months after discharge, and the events became less frequent after this period. A Cox proportional hazard model indicated LVEF ≤35% as an independent predictor for all-cause death and SCD. CONCLUSIONS: The incidence of SCD was relatively low in Japanese AMI patients treated with primary PCI, even in patients with LVEF ≤35% upon discharge. Careful management of patients with reduced LVEF is required to prevent SCD, especially in the early phase after discharge.
Assuntos
Infarto do Miocárdio , Intervenção Coronária Percutânea , Morte Súbita Cardíaca/epidemiologia , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/prevenção & controle , Hospitais , Humanos , Alta do Paciente , Fatores de Risco , Volume Sistólico , Resultado do Tratamento , Função Ventricular EsquerdaRESUMO
The optimal timing for initiating extracorporeal membrane oxygenation (ECMO) after starting mechanical ventilation has yet to be clarified. We report herein the cases of two patients with coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS) who were successfully managed with an early ECMO induction strategy. Case 1 involved a 64-year-old man admitted in respiratory distress with polymerase chain reaction-confirmed COVID-19. On day 5 at hospital, he was intubated, but oxygenation remained unimproved despite mechanical ventilation treatment with high positive end-expiratory pressure (PEEP) (PaO2/FiO2 [P/F] ratio, 127; Respiratory ECMO Survival Prediction [RESP] score, 4). ECMO was initiated 4 hours after intubation, and stopped on day 16 at hospital. The patient was discharged from hospital on day 36. Case 2 involved a 49-year-old man who had been admitted 8 days prior. He was intubated on hospital on day 2. High PEEP mechanical ventilation did not improve oxygenation (P/F ratio, 93; RESP score, 7). ECMO was stopped on hospital on day 7 and he was discharged from hospital on day 21. The strategy of early initiation of ECMO in these two cases may have minimized the risk of ventilation-related lung injury and contributed to the achievement of favorable outcomes.
Assuntos
COVID-19 , Oxigenação por Membrana Extracorpórea , Síndrome do Desconforto Respiratório , Masculino , Humanos , Pessoa de Meia-Idade , COVID-19/terapia , Estado Terminal/terapia , Síndrome do Desconforto Respiratório/terapia , Respiração ArtificialRESUMO
Pectin, a component of the plant cell wall, is involved in cell adhesion and environmental adaptations. We generated OsPG-FOX rice lines with little pectin due to overexpression of the gene encoding a pectin-degrading enzyme [polygalacturonase (PG)]. Overexpression of OsPG2 in rice under weak light conditions increased the activity of PG, which increased the degradation of pectin in the cell wall, thereby reducing adhesion. Under weak light conditions, the overexpression of OsPG decreased the pectin content and cell adhesion, resulting in abnormally large intercellular gaps and facilitating invasion by the rice blast fungus. OsPG2-FOX plants had weaker mechanical properties and greater sensitivity to biotic stresses than wild-type (WT) plants. However, the expression levels of disease resistance genes in non-infected leaves of OsPG2-FOX were more than twice as high as those of the WT and the intensity of disease symptoms was reduced, compared with the WT. Under normal light conditions, overexpression of OsPG2 decreased the pectin content, but did not affect cell adhesion and sensitivity to biotic stresses. Therefore, PG plays a role in regulating intercellular adhesion and the response to biotic stresses in rice.
Assuntos
Ascomicetos/patogenicidade , Parede Celular/química , Oryza/citologia , Oryza/microbiologia , Pectinas/química , Fenômenos Biomecânicos , Parede Celular/genética , Parede Celular/microbiologia , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno , Oryza/genética , Pectinas/metabolismo , Doenças das Plantas/microbiologia , Folhas de Planta/citologia , Folhas de Planta/genética , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas , Poligalacturonase/genética , Poligalacturonase/metabolismo , Regiões Promotoras Genéticas , Zea mays/genéticaRESUMO
In this study, we investigated the expression and functions of the transcription factor gene RDD4 (rice Dof daily fluctuations 4), which has sequence similarity to RDD1 that controls nutrient ion accumulation in rice. RDD4 protein was highly accumulated in leaf sheaths and localized to vascular bundles. RDD4-overexpressing plants (RDD4-OX) improved the accumulation of various nutrient ions, irrespective of nutrient concentration in a hydroponic solution. K+ and Cl- deficiencies induced the accumulation of other cations and anions, respectively. Interestingly, in RDD4-OX plants K+ and Cl- deficiencies increased PO4 3- and Mg2+ contents, respectively, despite opposite electric charges. Furthermore, PO4 3- deficiency induced NO3 - and Mg2+ accumulation in RDD4-OX plants. These data show that RDD4 is associated with the control of nutrient ion contents within plants. Also, photosynthetic CO2 assimilation in RDD4-OX plants was higher than in wild-type (WT) plants, although the sizes of shoots and panicles decreased in RDD4-OX plants. Subsequent microarray analysis indicated that OsFWL7, similar to maize CNR1 that negatively regulates plant size, showed the most significant difference in its expression levels between WT and RDD4-OX plants. Based on these results, it is hypothesized that a prominent increase in the OsFWL7 expression reduces plant size in RDD4-OX plants.
Assuntos
Oryza , Regulação da Expressão Gênica de Plantas , Íons , Nutrientes , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Individual interactions between glycans and their receptors are usually weak, although these weak interactions can combine to realize a strong interaction (multivalency). Such multivalency plays a crucial role in the recognition of host cells by pathogens. Glycodendrimers are useful materials for the reconstruction of this multivalent interaction. However, the introduction of a large number of glycans to a dendrimer core is fraught with difficulties. We herein synthesized antipathogenic glycodendrimers using the self-activating click chemistry (SACC) method developed by our group. The excellent reactivity of SACC enabled the efficient preparation of sialyl glycan and Gb3 glycan dendrimers, which exhibited strong avidity toward hemagglutinin on influenza virus and Shiga toxin B subunit produced by Escherichia coli, respectively. We demonstrated the usefulness of SACC-based glycodendrimers as antipathogenic compounds.
Assuntos
Química Click , Dendrímeros , PolissacarídeosRESUMO
To overcome a limitation to the breeding of autogamous crops, recurrent selection using transgenic male sterility (RSUTMS) has been proposed. In this system, negatively or positively selectable marker traits are required along with dominant transgenic male sterility. Anthocyanin pigmentation is an excellent marker trait. Two regulatory genes for MYB and bHLH and a structural gene for DFR are required for anthocyanin pigmentation in rice. Therefore, to apply anthocyanin pigmentation as a marker trait in various rice genotypes, coordinated expression of the three genes is required. In this study, we developed a leaf sheath-specific promoter and introduced three genes-DFR and C1/Myb, driven by the 35S promoter, and OsB2/bHLH, driven by the leaf sheath-specific promoter-into the rice genome. Leaf sheath-specific pigmentation was confirmed in all seven genotypes tested, which included japonica and indica cultivars. Analysis of genome sequence data from 25 cultivars showed that the strategy of conferring leaf sheath-specific anthocyanin pigmentation by introduction of these three genes would be effective for a wide range of genotypes and will be applicable to RSUTMS.
RESUMO
Enhanced renin-angiotensin activity contributes to hypertension, albuminuria, and glomerular hypertrophy. The angiotensin (Ang)-converting enzyme (ACE) 2/Ang (1-7)/Mas axis pathway acts against Ang II type 1 receptor (AT1R) signaling. We investigated whether olmesartan (Olm), an AT1R blocker, inhibits albuminuria independently of blood pressure and elucidated the potential mechanisms.Three- to 4-month-old male mice overexpressing renin in the liver (Ren-TG) were given olmesartan (5 mg/kg/day) or hydralazine (Hyd) (3.5 mg/kg/day) orally for 2 months. Ren-TG mice had higher systolic blood pressure (SBP) than wild-type (WT) mice (158.2 ± 6.3 versus 112.8 ± 8.8 mmHg, n = 3-4, P < 0.01). Ren-TG mice treated with Olm or Hyd for 2 months had lower SBP than untreated Ren-TG mice. Urinary albumin excretion (UAE) was significantly increased in Ren-TG mice compared with WT mice (78.2 ± 31.2 versus 28.6 ± 13.8 µg/day, n = 5-6, P < 0.01). Olm treatment for 2 months reduced UAE, whereas Hyd treatment did not. Olm treatment reversed decreased gene and protein expressions of ACE2 and Mas receptor (Mas 1) in the kidney of Ren-TG mice and inhibited enhanced NADPH oxidase (Nox) 4 expression, whereas Hyd treatment had no influence. Furthermore, increased reactive oxygen species (ROS) in the kidney of Ren-TG mice were decreased by Olm treatment but not by Hyd treatment.Olm treatment inhibits albuminuria and glomerular hypertrophy independently of blood pressure not only through its original AT1R blockade but also partly through the enhancement of the ACE2/Ang (1-7)/Mas axis and suppression of ROS generation.
Assuntos
Albuminúria/tratamento farmacológico , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Pressão Sanguínea , Imidazóis/uso terapêutico , Sistema Renina-Angiotensina/efeitos dos fármacos , Tetrazóis/uso terapêutico , Albuminúria/metabolismo , Albuminúria/fisiopatologia , Angiotensina I/metabolismo , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Enzima de Conversão de Angiotensina 2 , Animais , Biomarcadores/metabolismo , Western Blotting , Imidazóis/farmacologia , Masculino , Camundongos , NADPH Oxidases/metabolismo , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A/metabolismo , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Renina/metabolismo , Tetrazóis/farmacologiaRESUMO
We previously showed that J-waves were found more frequently in patients with low levels of serum eicosapentaenoic acid (EPA) in the acute phase of myocardial infarction, and were associated with the incidence of ischemia-related ventricular arrhythmias. However, the relationship between J-waves and serum EPA levels in a general population remains to be elucidated.The Iwaki Health Promotion Project is an ongoing community-based health promotion study in Iwaki, Hirosaki, which is in northern Japan. A total of 1,052 residents (mean age, 53.9 ± 15.4 years; 390 men) who participated in this project in 2014 were studied. A standard 12-lead electrocardiogram (ECG) was recorded and serum EPA levels were measured to evaluate the relationship between J-waves and serum EPA levels. J-waves were found in 52 (5%) subjects and were observed more frequently in male than female subjects (44 [11%] versus 8 [1%], P < 0.0001). More than half of the J-waves were the notched type (60%), and J-waves were detected most frequently in inferior leads on ECG (52%). The RR interval was longer and QTc duration shorter in subjects with J-waves than those without. No significant difference was found in serum EPA levels between subjects with and without J-waves (70 [49-116] versus 65 [41-106] µg/mL, P = 0.40). In multivariate analysis, male gender and RR interval were independent factors associated with the presence of J-waves.There was no significant relationship between J-waves and serum EPA levels in this general population in Japan. Various mechanisms for manifestation of the J-waves are suggested.
Assuntos
Eletrocardiografia/métodos , Infarto do Miocárdio , Taquicardia Ventricular , Adulto , Idoso , Ácido Eicosapentaenoico/sangue , Feminino , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/complicações , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/fisiopatologia , Vigilância da População/métodos , Fatores de Risco , Fatores Sexuais , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/fisiopatologiaRESUMO
Because environmental stress can reduce crop growth and yield, the identification of genes that enhance agronomic traits is increasingly important. Previous screening of full-length cDNA overexpressing (FOX) rice lines revealed that OsTIFY11b, one of 20 TIFY proteins in rice, affects plant size, grain weight, and grain size. Therefore, we analyzed the effect of OsTIFY11b and nine other TIFY genes on the growth and yield of corresponding TIFY-FOX lines. Regardless of temperature, grain weight and culm length were enhanced in lines overexpressing TIFY11 subfamily genes, except OsTIFY11e. The TIFY-FOX plants exhibited increased floret number and reduced days to flowering, as well as reduced spikelet fertility, and OsTIFY10b, in particular, enhanced grain yield by minimizing decreases in fertility. We suggest that the enhanced growth of TIFY-transgenic rice is related to regulation of the jasmonate signaling pathway, as in Arabidopsis. Moreover, we discuss the potential application of TIFY overexpression for improving crop yield.
Assuntos
Ciclopentanos/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/genética , Oxilipinas/metabolismo , Proteínas de Plantas/genética , Transdução de Sinais , Ciclopentanos/farmacologia , Flores/efeitos dos fármacos , Flores/crescimento & desenvolvimento , Expressão Gênica , Temperatura Alta , Oryza/citologia , Oryza/efeitos dos fármacos , Oxilipinas/farmacologia , Transdução de Sinais/efeitos dos fármacosRESUMO
Enhanced renin-angiotensin activity causes hypertension and cardiac hypertrophy. The angiotensin (Ang)-converting enzyme (ACE)2/Ang(1-7)/Mas axis pathway functions against Ang II type 1 receptor (AT1R) signaling. We investigated whether olmesartan (Olm), an AT1R blocker, inhibits cardiac hypertrophy independently of blood pressure, and evaluated the potential mechanisms. The 3- to 4-month-old male mice overexpressing renin in the liver (Ren-Tg) were given Olm (5 mg/kg/d) and hydralazine (Hyd) (3.5 mg/kg/d) orally for 2 months. Systolic blood pressure was higher in the Ren-Tg mice than in wild-type littermates. Olm and Hyd treatments lowered systolic blood pressure to the same degree. However, cardiac hypertrophy, evaluated by echocardiography, heart weight, cross-sectional area of cardiomyocytes, and gene expression, was inhibited by only Olm treatment, but not by Hyd. Olm treatment reversed decreased gene expressions of ACE2 and Mas receptor of Ren-Tg mice and inhibited enhanced NADPH oxidase (Nox)4 expression and reactive oxygen species, whereas Hyd treatment had no influence on them. These findings indicate that Olm treatment inhibits cardiac hypertrophy independently of blood pressure, not only through its original AT1R blockade but partly through enhancement of ACE2/Ang(1-7)/Mas axis and suppression of Nox4 expression.
Assuntos
Cardiomegalia/fisiopatologia , Hidralazina/farmacologia , Imidazóis/farmacologia , Receptor Tipo 1 de Angiotensina/biossíntese , Sistema Renina-Angiotensina/efeitos dos fármacos , Tetrazóis/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Fibrose/metabolismo , Expressão Gênica , Masculino , Camundongos , Miócitos Cardíacos/metabolismo , NADPH Oxidases/biossíntese , Espécies Reativas de Oxigênio/metabolismo , Renina/metabolismo , Transdução de SinaisRESUMO
The plant hormone jasmonate and its conjugates (JAs) have important roles in growth control, leaf senescence and defense responses against insects and microbial attacks. JA biosynthesis is induced by several stresses, including mechanical wounding, pathogen attacks, drought and salinity stresses. However, the roles of JAs under abiotic stress conditions are unclear. Here we report that increased expression of the Cyt P450 family gene CYP94C2b enhanced viability of rice plants under saline conditions. This gene encodes an enzyme closely related to CYP94C1 that catalyzes conversion of bioactive jasmonate-isoleucine (JA-Ile) into 12OH-JA-Ile and 12COOH-JA-Ile. Inactivation of JA was facilitated in a rice line with enhanced CYP94C2b expression, and responses to exogenous JA and wounding were alleviated. Moreover, salt stress-induced leaf senescence but not natural senescence was delayed in the transgenic rice. These results suggest that bioactive JAs have a negative effect on viability under salt stress conditions and demonstrate that manipulating JA metabolism confers enhanced salt tolerance in rice.
Assuntos
Ciclopentanos/farmacologia , Sistema Enzimático do Citocromo P-450/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Família Multigênica , Oryza/genética , Oxilipinas/farmacologia , Tolerância ao Sal/genética , Proliferação de Células/efeitos dos fármacos , Sistema Enzimático do Citocromo P-450/metabolismo , Genes de Plantas , Oryza/citologia , Oryza/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/genética , Salinidade , Tolerância ao Sal/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacosRESUMO
Environmental stress tolerance is an important trait for crop improvement. In recent decades, numerous genes that confer tolerance to abiotic stress such as salinity were reported. However, the levels of salt tolerance differ greatly depending on growth conditions, and mechanisms underlying the complicated nature of stress tolerance are far from being fully understood. In this study, we investigated the profiles of stress tolerance of nine salt-tolerant rice varieties and transgenic rice lines carrying constitutively expressed genes that are potentially involved in salt tolerance, by evaluating their growth and viability under salt, heat, ionic and hyperosmotic stress conditions. Profiling of the extant varieties and selected chromosome segment substitution lines showed that salt tolerance in a greenhouse condition was more tightly correlated with ionic stress tolerance than osmotic stresses. In Nona Bokra, one of the most salt-tolerant varieties, the contribution of the previously identified sodium transporter HKT1;5 to salt tolerance was fairly limited. In addition, Nona Bokra exhibited high tolerance to all the stresses imposed. More surprisingly, comparative evaluation of 74 stress tolerance genes revealed that the most striking effect to enhance salt tolerance was conferred by overexpressing CYP94C2b, which promotes deactivation of jasmonate. In contrast, genes encoding ABA signaling factors conferred multiple stress tolerance. Genes conferring tolerance to both heat and hyperosmotic stresses were preferentially linked to functional categories related to heat shock proteins, scavenging of reactive oxygen species and Ca(2+) signaling. These comparative profiling data provide a new basis for understanding the ability of plants to grow under harsh environmental conditions.
Assuntos
Regulação da Expressão Gênica de Plantas , Oryza/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Plantas Tolerantes a Sal/genética , Ciclopentanos/farmacologia , Secas , Temperatura Alta , Oryza/efeitos dos fármacos , Pressão Osmótica/efeitos dos fármacos , Oxilipinas/farmacologia , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Tolerantes a Sal/efeitos dos fármacos , Cloreto de Sódio/farmacologiaRESUMO
Superoxide dismutase (SOD) is widely assumed to play a role in the detoxification of reactive oxygen species caused by environmental stresses. We found a characteristic expression of manganese SOD 1 (MSD1) in a heat-stress-tolerant cultivar of rice (Oryza sativa). The deduced amino acid sequence contains a signal sequence and an N-glycosylation site. Confocal imaging analysis of rice and onion cells transiently expressing MSD1-YFP showed MSD1-YFP in the Golgi apparatus and plastids, indicating that MSD1 is a unique Golgi/plastid-type SOD. To evaluate the involvement of MSD1 in heat-stress tolerance, we generated transgenic rice plants with either constitutive high expression or suppression of MSD1. The grain quality of rice with constitutive high expression of MSD1 grown at 33/28 °C, 12/12 h, was significantly better than that of the wild type. In contrast, MSD1-knock-down rice was markedly susceptible to heat stress. Quantitative shotgun proteomic analysis indicated that the overexpression of MSD1 up-regulated reactive oxygen scavenging, chaperone and quality control systems in rice grains under heat stress. We propose that the Golgi/plastid MSD1 plays an important role in adaptation to heat stress.
Assuntos
Complexo de Golgi/enzimologia , Resposta ao Choque Térmico/fisiologia , Oryza/fisiologia , Plastídeos/enzimologia , Superóxido Dismutase/fisiologia , Sequência de Aminoácidos , Técnicas de Silenciamento de Genes , Microscopia Confocal , Dados de Sequência Molecular , Oryza/enzimologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/fisiologia , Sementes/crescimento & desenvolvimento , Superóxido Dismutase/genéticaRESUMO
Heme activator protein (HAP), also known as nuclear factor Y or CCAAT binding factor (HAP/NF-Y/CBF), has important functions in regulating plant growth, development and stress responses. The expression of rice HAP gene (OsHAP2E) was induced by probenazole (PBZ), a chemical inducer of disease resistance. To characterize the gene, the chimeric gene (OsHAP2E::GUS) engineered to carry the structural gene encoding ß-glucuronidase (GUS) driven by the promoter from OsHAP2E was introduced into rice. The transgenic lines of OsHAP2Ein::GUS with the intron showed high GUS activity in the wounds and surrounding tissues. When treated by salicylic acid (SA), isonicotinic acid (INA), abscisic acid (ABA) and hydrogen peroxide (H2 O2 ), the lines showed GUS activity exclusively in vascular tissues and mesophyll cells. This activity was enhanced after inoculation with Magnaporthe oryzae or Xanthomonas oryzae pv. oryzae. The OsHAP2E expression level was also induced after inoculation of rice with M. oryzae and X. oryzae pv. oryzae and after treatment with SA, INA, ABA and H2 O2, respectively. We further produced transgenic rice overexpressing OsHAP2E. These lines conferred resistance to M. oryzae or X. oryzae pv. oryzae and to salinity and drought. Furthermore, they showed a higher photosynthetic rate and an increased number of tillers. Microarray analysis showed up-regulation of defence-related genes. These results suggest that this gene could contribute to conferring biotic and abiotic resistances and increasing photosynthesis and tiller numbers.
Assuntos
Resistência à Doença/genética , Secas , Oryza/anatomia & histologia , Oryza/genética , Fotossíntese , Doenças das Plantas/genética , Proteínas de Plantas/genética , Salinidade , Resistência à Doença/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Glucuronidase/metabolismo , Magnaporthe/fisiologia , Dados de Sequência Molecular , Oryza/efeitos dos fármacos , Oryza/microbiologia , Pressão Osmótica/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Doenças das Plantas/imunologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Tiazóis/farmacologia , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética , Xanthomonas/fisiologiaRESUMO
The meristem initiates lateral organs in a regular manner, and proper communication between the meristem and the lateral organs ensures the normal development of plants. Here, we show that mutation of the rice (Oryza sativa) gene TONGARI-BOUSHI1 (TOB1) results in pleiotropic phenotypes in spikelets, such as the formation of a cone-shaped organ instead of the lemma or palea, the development of two florets in a spikelet, or premature termination of the floret meristem, in addition to reduced growth of the lemma or palea and elongation of the awn. These phenotypes seem to result from not only failure in growth of the lateral organs, but also defects in maintenance and organization of the meristem. For example, the cone-shaped organ develops as a ring-like primordium from an initial stage, suggesting that regulation of organ initiation in the meristem may be compromised. TOB1 encodes a YABBY protein, which is closely related to FILAMENTOUS FLOWER in Arabidopsis thaliana, and is expressed in the lateral organ primordia without any patterns of polarization. No TOB1 expression is detected in the meristem, so TOB1 may act non-cell autonomously to maintain proper meristem organization and is therefore likely to play an important role in rice spikelet development.
Assuntos
Meristema/crescimento & desenvolvimento , Meristema/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Meristema/genética , Dados de Sequência Molecular , Oryza/genética , Proteínas de Plantas/genéticaRESUMO
Plants respond to pathogen attack by transcriptionally regulating defense-related genes via various types of transcription factors. We identified a transcription factor in rice, OsNAC111, belonging to the TERN subgroup of the NAC family that was transcriptionally upregulated after rice blast fungus (Magnaporthe oryzae) inoculation. OsNAC111 was localized in the nucleus of rice cells and had transcriptional activation activity in yeast and rice cells. Transgenic rice plants overexpressing OsNAC111 showed increased resistance to the rice blast fungus. In OsNAC111-overexpressing plants, the expression of several defense-related genes, including pathogenesis-related (PR) genes, was constitutively high compared with the control. These genes all showed blast disease-responsive expression in leaves. Among them, two chitinase genes and one ß-1,3-glucanase gene showed reduced expression in transgenic rice plants in which OsNAC111 function was suppressed by a chimeric repressor (OsNAC111-SRDX). OsNAC111 activated transcription from the promoters of the chitinase and ß-1,3-glucanase genes in rice cells. In addition, brown pigmentation at the infection sites, a defense response of rice cells to the blast fungus, was lowered in OsNAC111-SRDX plants at the early infection stage. These results indicate that OsNAC111 positively regulates the expression of a specific set of PR genes in the disease response and contributes to disease resistance.
Assuntos
Resistência à Doença , Regulação da Expressão Gênica de Plantas , Magnaporthe/fisiologia , Oryza/genética , Doenças das Plantas/imunologia , Fatores de Transcrição/metabolismo , Quitinases/genética , Regulação para Baixo , Perfilação da Expressão Gênica , Genes Reporter , Glucana 1,3-beta-Glucosidase/genética , Interações Hospedeiro-Patógeno , Análise de Sequência com Séries de Oligonucleotídeos , Oryza/imunologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Proteínas Recombinantes de Fusão , Fatores de Transcrição/genética , Regulação para CimaRESUMO
Strigolactones (SLs) are a group of phytohormones that control plant growth and development including shoot branching. Previous studies of the phenotypes of SL-related rice (Oryza sativa) dwarf (d) mutants demonstrated that SLs inhibit mesocotyl elongation by controlling cell division. Here, we found that the expression of cytokinin (CK)-responsive type-A RESPONSE REGULATOR (RR) genes was higher in d10-1 and d14-1 mutants than in the wild type. However, CK levels in mesocotyls of the d mutants were not very different from those in the wild type. On the other hand, application of a synthetic CK (kinetin) enhanced mesocotyl elongation in the d mutants and the wild type. d10-1 and d14-1 mesocotyls were more sensitive to CK than wild-type mesocotyls, suggesting that the up-regulation of the CK-responsive type-A RR genes and the higher elongation of mesocotyls in the d mutants are mainly due to the increased sensitivity of the d mutants to CK. Co-treatment with kinetin and a synthetic SL (GR24) confirmed the antagonistic functions of SL and CK on mesocotyl elongation. OsTCP5, which encodes a transcription factor belonging to the cell division-regulating TCP family, was also regulated by SL and CK and its expression was negatively correlated with mesocotyl length. These findings suggest that OsTCP5 contributes to the SL- and CK-controlled mesocotyl elongation in darkness.