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1.
Plants (Basel) ; 13(8)2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38674547

RESUMO

Conferring crops with resistance to multiple diseases is crucial for stable food production. Genetic engineering is an effective means of achieving this. The rice receptor-like cytoplasmic kinase BSR1 mediates microbe-associated molecular pattern-induced immunity. In our previous study, we demonstrated that rice lines overexpressing BSR1 under the control of the maize ubiquitin promoter exhibited broad-spectrum resistance to rice blast, brown spot, leaf blight, and bacterial seedling rot. However, unfavorable phenotypes were observed, such as a decreased seed germination rate and a partial darkening of husked rice. Herein, we present a strategy to address these unfavorable phenotypes using an OsUbi7 constitutive promoter with moderate expression levels and a pathogen-inducible PR1b promoter. Rice lines expressing BSR1 under the influence of both promoters maintained broad-spectrum disease resistance. The seed germination rate and coloration of husked rice were similar to those of the wild-type rice.

2.
Int J Mol Sci ; 24(12)2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37373546

RESUMO

Crops experience herbivory by arthropods and microbial infections. In the interaction between plants and chewing herbivores, lepidopteran larval oral secretions (OS) and plant-derived damage-associated molecular patterns (DAMPs) trigger plant defense responses. However, the mechanisms underlying anti-herbivore defense, especially in monocots, have not been elucidated. The receptor-like cytoplasmic kinase Broad-Spectrum Resistance 1 (BSR1) of Oryza sativa L. (rice) mediates cytoplasmic defense signaling in response to microbial pathogens and enhances disease resistance when overexpressed. Here, we investigated whether BSR1 contributes to anti-herbivore defense responses. BSR1 knockout suppressed rice responses triggered by OS from the chewing herbivore Mythimna loreyi Duponchel (Lepidoptera: Noctuidae) and peptidic DAMPs OsPeps, including the activation of genes required for biosynthesis of diterpenoid phytoalexins (DPs). BSR1-overexpressing rice plants exhibited hyperactivation of DP accumulation and ethylene signaling after treatment with simulated herbivory and acquired enhanced resistance to larval feeding. As the biological significance of herbivory-induced accumulation of rice DPs remains unexplained, their physiological activities in M. loreyi were analyzed. The addition of momilactone B, a rice DP, to the artificial diet suppressed the growth of M. loreyi larvae. Altogether, this study revealed that BSR1 and herbivory-induced rice DPs are involved in the defense against chewing insects, in addition to pathogens.


Assuntos
Mariposas , Oryza , Animais , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Herbivoria/fisiologia , Transdução de Sinais , Mariposas/fisiologia , Plantas/metabolismo , Larva/metabolismo , Regulação da Expressão Gênica de Plantas
3.
Int J Mol Sci ; 24(4)2023 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-36835053

RESUMO

Sugarcane smut caused by Sporisorium scitamineum is one of the most devastating sugarcane diseases. Furthermore, Rhizoctonia solani causes severe diseases in various crops including rice, tomato, potato, sugar beet, tobacco, and torenia. However, effective disease-resistant genes against these pathogens have not been identified in target crops. Therefore, the transgenic approach can be used since conventional cross-breeding is not applicable. Herein, the overexpression of BROAD-SPECTRUM RESISTANCE 1 (BSR1), a rice receptor-like cytoplasmic kinase, was conducted in sugarcane, tomato and torenia. BSR1-overexpressing tomatoes exhibited resistance to the bacteria Pseudomonas syringae pv. tomato DC3000 and the fungus R. solani, whereas BSR1-overexpressing torenia showed resistance to R. solani in the growth room. Additionally, BSR1 overexpression conferred resistance to sugarcane smut in the greenhouse. These three BSR1-overexpressing crops exhibited normal growth and morphologies except in the case of exceedingly high levels of overexpression. These results indicate that BSR1 overexpression is a simple and effective tool for conferring broad-spectrum disease resistance to many crops.


Assuntos
Infecções Bacterianas , Oryza , Saccharum , Solanum lycopersicum , Ustilaginales , Oryza/genética , Saccharum/genética , Melhoramento Vegetal , Resistência à Doença/genética , Doenças das Plantas/microbiologia , Regulação da Expressão Gênica de Plantas
4.
Int J Mol Sci ; 23(9)2022 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-35563126

RESUMO

Plant pathogens evade basal defense systems and attack different organs and tissues of plants. Genetic engineering of plants with genes that confer resistance against pathogens is very effective in pathogen control. Conventional breeding for disease resistance in ornamental crops is difficult and lagging relative to that in non-ornamental crops due to an inadequate number of disease-resistant genes. Therefore, genetic engineering of these plants with defense-conferring genes is a practical approach. We used rice BSR2 encoding CYP78A15 for developing transgenic Torenia fournieri Lind. lines. The overexpression of BSR2 conferred resistance against two devastating fungal pathogens, Rhizoctonia solani and Botrytis cinerea. In addition, BSR2 overexpression resulted in enlarged flowers with enlarged floral organs. Histological observation of the petal cells suggested that the enlargement in the floral organs could be due to the elongation and expansion of the cells. Therefore, the overexpression of BSR2 confers broad-spectrum disease resistance and induces the production of enlarged flowers simultaneously. Therefore, this could be an effective strategy for developing ornamental crops that are disease-resistant and economically more valuable.


Assuntos
Lamiales , Oryza , Resistência à Doença/genética , Flores/genética , Regulação da Expressão Gênica de Plantas , Lamiales/genética , Oryza/genética , Melhoramento Vegetal , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Plantas Geneticamente Modificadas/genética
5.
Plant Cell Rep ; 39(11): 1493-1503, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32772129

RESUMO

KEY MESSAGE: The overexpression of rice BSR2 would offer a simple and effective strategy to protect plants from multiple devastating diseases in tomato and Arabidopsis. Many devastating plant diseases are caused by pathogens possessing a wide host range. Fungal Botrytis cinerea and Rhizoctonia solani, as well as bacterial Pseudomonas syringae and Ralstonia pseudosolanacearum are four such pathogens that infect hundreds of plant species, including agronomically important crops, and cause serious diseases, leading to severe economic losses. However, reports of genes that can confer resistance to broad host-range pathogens via traditional breeding methods are currently limited. We previously reported that Arabidopsis plants overexpressing rice BROAD-SPECTRUM RESISTANCE2 (BSR2/CYP78A15) showed tolerance not only to bacterial P. syringae pv. tomato DC3000 but also to fungal Colletotrichum higginsianum and R. solani. Rice plants overexpressing BSR2 displayed tolerance to two R. solani anastomosis groups. In the present study, first, BSR2-overexpressing (OX) Arabidopsis plants were shown to be additionally tolerant to B. cinerea, R. solani, and R. pseudosolanacearum. Next, tomato 'Micro-Tom' was used as a model to determine whether such tolerance by BSR2 can be introduced into dicot crops to prevent infection from pathogens possessing wide host range. BSR2-OX tomato displayed broad-spectrum disease tolerance to fungal B. cinerea and R. solani, as well as to bacterial P. syringae and R. pseudosolanacearum. Additionally, undesirable traits such as morphological changes were not detected. Thus, BSR2 overexpression can offer a simple and effective strategy to protect crops from multiple destructive diseases.


Assuntos
Arabidopsis/genética , Arabidopsis/microbiologia , Resistência à Doença/genética , Solanum lycopersicum/genética , Solanum lycopersicum/microbiologia , Botrytis/patogenicidade , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Oryza/genética , Doenças das Plantas/microbiologia , Plantas Geneticamente Modificadas/genética , Pseudomonas syringae/patogenicidade , Ralstonia/patogenicidade , Rhizoctonia/patogenicidade
6.
Surg Case Rep ; 5(1): 120, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31342204

RESUMO

BACKGROUND: Primary leiomyosarcoma (LMS) of vascular origin is a rare lesion, and patients with LMS of vascular origin have poorer prognoses than patients with LMS of other origins. The inferior vena cava is the most commonly affected vessel and accounts for 60% of all vascular cases. However, LMS originating from the ovarian vein is extremely rare, and we are only aware of 15 reported cases. Therefore, we report our experience with a case of LMS originating from the right ovarian vein and review the related literature. CASE PRESENTATION: A 71-year-old Japanese woman with no symptoms was admitted to our hospital because of abnormal findings in a routine abdominal ultrasonography check-up. Contrast-enhanced computed tomography of the abdomen revealed a well-defined, lobulated solid mass with a diameter of 5.5 cm in the right retroperitoneal space. The mass exhibited relatively low uptake during 18F-fluorodeoxyglucose positron emission tomography. Based on these findings, the differential diagnosis included a retroperitoneal tumor, such as a desmoid tumor, leiomyoma, LMS, and malignant mesothelioma. Operative findings confirmed that the mass had originated from the right ovarian vessels, and en bloc excision was performed for the mass and the right ovarian vessels. The final pathological diagnosis was LMS originating from the right ovarian vein, and the surgical resection margins were free from tumor cells. After histological findings confirmed the LMS diagnosis, the patient underwent adjuvant radiation therapy and has not exhibited signs of local recurrence or metastasis in the 6 months after surgery. CONCLUSIONS: We encountered a 71-year-old woman with LMS originating from her right ovarian vein. The prognosis of vascular LMS is generally poor. Therefore, careful follow-up will be required for our patient.

7.
Sci Rep ; 9(1): 587, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30679785

RESUMO

The fungal pathogen Rhizoctonia solani causes devastating diseases in hundreds of plant species. Among these, R. solani causes sheath blight, one of the three major diseases in rice. To date, few genes have been reported that confer resistance to R. solani. Here, rice-FOX Arabidopsis lines identified as having resistance to a bacterial pathogen, Pseudomonas syringae pv. tomato DC3000, and a fungal pathogen, Colletotrichum higginsianum were screened for disease resistance to R. solani. BROAD-SPECTRUM RESISTANCE2 (BSR2), a gene encoding an uncharacterized cytochrome P450 protein belonging to the CYP78A family, conferred resistance to R. solani in Arabidopsis. When overexpressed in rice, BSR2 also conferred resistance to two R. solani anastomosis groups. Both Arabidopsis and rice plants overexpressing BSR2 had slower growth and produced longer seeds than wild-type control plants. In contrast, BSR2-knockdown rice plants were more susceptible to R. solani and displayed faster growth and shorter seeds in comparison with the control. These results indicate that BSR2 is associated with disease resistance, growth rate and seed size in rice and suggest that its function is evolutionarily conserved in both monocot rice and dicot Arabidopsis.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Sistema Enzimático do Citocromo P-450/metabolismo , Resistência à Doença , Oryza/crescimento & desenvolvimento , Doenças das Plantas/imunologia , Rhizoctonia/crescimento & desenvolvimento , Arabidopsis/anatomia & histologia , Arabidopsis/genética , Arabidopsis/microbiologia , Sistema Enzimático do Citocromo P-450/genética , Expressão Gênica , Oryza/anatomia & histologia , Oryza/genética , Oryza/microbiologia , Doenças das Plantas/microbiologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
8.
Plant J ; 96(6): 1137-1147, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30222251

RESUMO

Plants have evolved many receptor-like cytoplasmic kinases (RLCKs) to modulate their growth, development, and innate immunity. Broad-Spectrum Resistance 1 (BSR1) encodes a rice RLCK, whose overexpression confers resistance to multiple diseases, including fungal rice blast and bacterial leaf blight. However, the mechanisms underlying resistance remain largely unknown. In the present study, we report that BSR1 is a functional protein kinase that autophosphorylates and transphosphorylates an artificial substrate in vitro. Although BSR1 is classified as a serine/threonine kinase, it was shown to autophosphorylate on tyrosine as well as on serine/threonine residues when expressed in bacteria, demonstrating that it is a dual-specificity kinase. Protein kinase activity was found to be indispensable for resistance to rice blast and leaf blight in BSR1-overexpressing plants. Importantly, tyrosine phosphorylation of BSR1 was critical for proper localization of BSR1 in rice cells and played a crucial role in BSR1-mediated resistance to multiple diseases, as evidenced by compromised disease resistance in transgenic plants overexpressing a mutant BSR1 in which Tyr-63 was substituted with Ala. Overall, our data indicate that BSR1 is a non-receptor dual-specificity kinase and that both tyrosine and serine/threonine kinase activities are critical for the normal functioning of BSR1 in the resistance to multiple pathogens. Our results support the notion that tyrosine phosphorylation plays a major regulatory role in the transduction of defense signals from cell-surface receptor complexes to downstream signaling components in plants.


Assuntos
Resistência à Doença , Oryza/imunologia , Proteínas de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Oryza/enzimologia , Oryza/fisiologia , Fosforilação , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Proteínas Serina-Treonina Quinases/fisiologia , Ácido Salicílico/metabolismo , Tirosina
9.
Biosci Biotechnol Biochem ; 81(8): 1497-1502, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28521637

RESUMO

Broad-Spectrum Resistance 1 (BSR1) encodes a rice receptor-like cytoplasmic kinase, and enhances disease resistance when overexpressed. Rice plants overexpressing BSR1 are highly resistant to diverse pathogens, including rice blast fungus. However, the mechanism responsible for this resistance has not been fully characterized. To analyze the BSR1 function, BSR1-knockout (BSR1-KO) plants were generated using a clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system. Experiments using suspension-cultured cells revealed that defense responses including H2O2 production (i.e. oxidative burst) and expression of defense-related genes induced by autoclaved conidia of the rice blast fungus significantly decreased in BSR1-KO cells. Furthermore, a treatment with chitin oligomers which function as microbe-associated molecular patterns (MAMPs) of the rice blast fungus resulted in considerably suppressed defense responses in BSR1-KO cells. These results suggest that BSR1 is important for the rice innate immunity triggered by the perception of chitin.


Assuntos
Quitina/imunologia , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Oryza/imunologia , Doenças das Plantas/imunologia , Transdução de Sinais/imunologia , Sequência de Bases , Sistemas CRISPR-Cas , Técnicas de Cultura de Células , Quitina/genética , Técnicas de Inativação de Genes , Peróxido de Hidrogênio/imunologia , Peróxido de Hidrogênio/metabolismo , Magnaporthe/patogenicidade , Magnaporthe/fisiologia , Oryza/genética , Oryza/microbiologia , Células Vegetais/imunologia , Células Vegetais/metabolismo , Células Vegetais/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Plantas Geneticamente Modificadas , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/imunologia , Transdução de Sinais/genética
10.
Breed Sci ; 66(3): 396-406, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27436950

RESUMO

Broad-spectrum disease resistance against two or more types of pathogen species is desirable for crop improvement. In rice, Xanthomonas oryzae pv. oryzae (Xoo), the causal bacteria of rice leaf blight, and Magnaporthe oryzae, the fungal pathogen causing rice blast, are two of the most devastating pathogens. We identified the rice BROAD-SPECTRUM RESISTANCE 1 (BSR1) gene for a BIK1-like receptor-like cytoplasmic kinase using the FOX hunting system, and demonstrated that BSR1-overexpressing (OX) rice showed strong resistance to the bacterial pathogen, Xoo and the fungal pathogen, M. oryzae. Here, we report that BSR1-OX rice showed extended resistance against two other different races of Xoo, and to at least one other race of M. oryzae. In addition, the rice showed resistance to another bacterial species, Burkholderia glumae, which causes bacterial seedling rot and bacterial grain rot, and to Cochliobolus miyabeanus, another fungal species causing brown spot. Furthermore, BSR1-OX rice showed slight resistance to rice stripe disease, a major viral disease caused by rice stripe virus. Thus, we demonstrated that BSR1-OX rice shows remarkable broad-spectrum resistance to at least two major bacterial species and two major fungal species, and slight resistance to one viral pathogen.

11.
Plant J ; 84(6): 1100-13, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26506081

RESUMO

Rice (Oryza sativa) produces diterpenoid phytoalexins (DPs), momilactones and phytocassanes as major phytoalexins. Accumulation of DPs is induced in rice by blast fungus infection, copper chloride or UV light. Here, we describe a rice transcription factor named diterpenoid phytoalexin factor (DPF), which is a basic helix-loop-helix (bHLH) transcription factor. The gene encoding DPF is expressed mainly in roots and panicles, and is inducible in leaves by blast infection, copper chloride or UV. Expression of all DP biosynthetic genes and accumulation of momilactones and phytocassanes were remarkably increased and decreased in DPF over-expressing and DPF knockdown rice, respectively. These results clearly demonstrated that DPF positively regulates DP accumulation via transcriptional regulation of DP biosynthetic genes, and plays a central role in the biosynthesis of DPs in rice. Furthermore, DPF activated the promoters of COPALYL DIPHOSPHATE SYNTHASE2 (CPS2) and CYTOCHROME P450 MONOOXYGENASE 99A2 (CYP99A2), whose products are implicated in the biosynthesis of phytocassanes and momilactones, respectively. Mutations in the N-boxes in the CPS2 upstream region, to which several animal bHLH transcription factors bind, decreased CPS2 transcription, indicating that DPF positively regulates CPS2 transcription through the N-boxes. In addition, DPF partly regulates CYP99A2 through the N-box. This study demonstrates that DPF acts as a master transcription factor in DP biosynthesis.


Assuntos
Diterpenos/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Sesquiterpenos/metabolismo , Fatores de Transcrição/metabolismo , Regulação para Baixo , Regulação da Expressão Gênica de Plantas/fisiologia , Oryza/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Regulação para Cima , Fitoalexinas
12.
Plant Biotechnol J ; 9(4): 466-85, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-20955180

RESUMO

Approximately 20,000 of the rice-FOX Arabidopsis transgenic lines, which overexpress 13,000 rice full-length cDNAs at random in Arabidopsis, were screened for bacterial disease resistance by dip inoculation with Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The identities of the overexpressed genes were determined in 72 lines that showed consistent resistance after three independent screens. Pst DC3000 resistance was verified for 19 genes by characterizing other independent Arabidopsis lines for the same genes in the original rice-FOX hunting population or obtained by reintroducing the genes into ecotype Columbia by floral dip transformation. Thirteen lines of these 72 selections were also resistant to the fungal pathogen Colletotrichum higginsianum. Eight genes that conferred resistance to Pst DC3000 in Arabidopsis have been introduced into rice for overexpression, and transformants were evaluated for resistance to the rice bacterial pathogen, Xanthomonas oryzae pv. oryzae. One of the transgenic rice lines was highly resistant to Xanthomonas oryzae pv. oryzae. Interestingly, this line also showed remarkably high resistance to Magnaporthe grisea, the fungal pathogen causing rice blast, which is the most devastating rice disease in many countries. The causal rice gene, encoding a putative receptor-like cytoplasmic kinase, was therefore designated as BROAD-SPECTRUM RESISTANCE 1. Our results demonstrate the utility of the rice-FOX Arabidopsis lines as a tool for the identification of genes involved in plant defence and suggest the presence of a defence mechanism common between monocots and dicots.


Assuntos
Arabidopsis/genética , Arabidopsis/microbiologia , Oryza/genética , Oryza/microbiologia , Doenças das Plantas/genética , Pseudomonas syringae/patogenicidade , Arabidopsis/enzimologia , Clonagem Molecular , Colletotrichum/patogenicidade , Regulação da Expressão Gênica de Plantas , Variação Genética , Imunidade Inata , Magnaporthe/patogenicidade , Oryza/enzimologia , Doenças das Plantas/microbiologia , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/microbiologia , Transgenes , Xanthomonas/patogenicidade
13.
Plant Mol Biol ; 71(4-5): 391-402, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19653105

RESUMO

Plant growth and crop production are limited by environmental stress. We used a large population of transgenic Arabidopsis expressing rice full-length cDNAs to isolate the rice genes that improve the tolerance of plants to environmental stress. By sowing T2 seeds of the transgenic lines under conditions of salinity stress, the salt-tolerant line R07047 was isolated. It expressed a rice gene, OsSMCP1, which encodes a small protein with a single C2 domain, a Ca(2+)-dependent membrane-targeting domain. Retransformation of wild-type Arabidopsis revealed that OsSMCP1 is responsible for conferring the salt tolerance. It is particularly interesting that R07047 and newly constructed OsSMCP1-overexpressing Arabidopsis showed enhanced tolerance not only to high salinity but also to osmotic, dehydrative, and oxidative stresses. Furthermore, R07047 showed improved resistance to Pseudomonas syringae. The OsSMCP1 expression in rice is constitutive. Particle-bombardment-mediated transient expression analysis revealed that OsSMCP1 is targeted to plastids in rice epidermal cells. It induced overexpression of several nuclear encoded genes, including the stress-associated genes, in transgenic Arabidopsis. No marked morphological change or growth retardation was observed in R07047 or retransformants. For molecular breeding to improve the tolerance of crops against environmental stress, OsSMCP1 is a promising candidate.


Assuntos
Arabidopsis/fisiologia , Secas , Regulação da Expressão Gênica de Plantas , Oryza/genética , Pressão Osmótica , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas/fisiologia , Sequência de Aminoácidos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/microbiologia , Sequência de Bases , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Peróxido de Hidrogênio/farmacologia , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Estresse Oxidativo/efeitos dos fármacos , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/microbiologia , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/microbiologia , Pseudomonas syringae/patogenicidade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sais/farmacologia , Alinhamento de Sequência
14.
Mol Plant Microbe Interact ; 22(7): 820-9, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19522564

RESUMO

Fatty acids and their derivatives play important signaling roles in plant defense responses. It has been shown that suppressing a gene for stearoyl acyl carrier protein fatty-acid desaturase (SACPD) enhances the resistance of Arabidopsis (SSI2) and soybean to multiple pathogens. In this study, we present functional analyses of a rice homolog of SSI2 (OsSSI2) in disease resistance of rice plants. A transposon insertion mutation (Osssi2-Tos17) and RNAi-mediated knockdown of OsSSI2 (OsSSI2-kd) reduced the oleic acid (18:1) level and increased that of stearic acid (18:0), indicating that OsSSI2 is responsible for fatty-acid desaturase activity. These plants displayed spontaneous lesion formation in leaf blades, retarded growth, slight increase in endogenous free salicylic acid (SA) levels, and SA/benzothiadiazole (BTH)-specific inducible genes, including WRKY45, a key regulator of SA/BTH-induced resistance, in rice. Moreover, the OsSSI2-kd plants showed markedly enhanced resistance to the blast fungus Magnaporthe grisea and leaf-blight bacteria Xanthomonas oryzae pv. oryzae. These results suggest that OsSSI2 is involved in the negative regulation of defense responses in rice, as are its Arabidopsis and soybean counterparts. Microarray analyses identified 406 genes that were differentially expressed (>or=2-fold) in OsSSI2-kd rice plants compared with wild-type rice and, of these, approximately 39% were BTH responsive. Taken together, our results suggest that induction of SA-responsive genes, including WRKY45, is likely responsible for enhanced disease resistance in OsSSI2-kd rice plants.


Assuntos
Ácidos Graxos Dessaturases/fisiologia , Oryza/enzimologia , Doenças das Plantas/genética , Proteínas de Plantas/fisiologia , Ácidos Graxos Dessaturases/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Glicerol/farmacologia , Imunidade Inata/genética , Magnaporthe/fisiologia , Família Multigênica , Análise de Sequência com Séries de Oligonucleotídeos , Oryza/efeitos dos fármacos , Oryza/microbiologia , Oryza/fisiologia , Filogenia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Ácido Salicílico/metabolismo , Xanthomonas/fisiologia
15.
Langmuir ; 25(15): 8428-33, 2009 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-19292429

RESUMO

A lipophilic L-glutamide-derived lipid with a triethoxysilyl headgroup (Si-lipid) was newly synthesized as a self-assembling organogelator to stabilize the chirally ordered state of the aggregates. The Si-lipid formed nanofibrous network structures in various organic solvents such as benzene, cyclohexane, and dimethylformamide and entrapped them to form gels. The gels were transformed to sols by heat, and this gel-to-sol transition was thermally reversible. Polycondensation of the triethoxysilyl groups was carried out by acid-catalyzed hydrolysis and condensation in a benzene gel and confirmed by 29Si CP/MAS NMR and FT-IR measurements. After polycondensation, a gel state was maintained, and the thermal and mechanical stabilities of the aggregates increased markedly. Interestingly, polycondensation in chloroform and acetonitrile induced gelation, whereas no gelation was observed before polycondensation. Xerogel, which was prepared by freeze drying organogels, had fibrous network structures similar to those of the original gels. A strong CD signal was observed around the amide bonds in a cyclohexane gel at 20 degrees C, indicating that the gel contained chirally oriented structures based on intermolecular hydrogen bonds. An enhanced CD signal was observed even after polycondensation of the ethoxysilyl group of Si-lipid (poly(Si-lipid)) and was maintained at 70 degrees C, which is above the temperature of the gel-to-sol phase transition of the original gel. These results indicate that the formation of siloxane network structure among the fibrous aggregates stabilizes the chiral orientation of lipid aggregates.


Assuntos
Ácido Glutâmico/química , Silício/química , Varredura Diferencial de Calorimetria/métodos , Catálise , Dicroísmo Circular , Géis/química , Hidrólise , Lipídeos/química , Espectroscopia de Ressonância Magnética , Teste de Materiais , Microscopia Eletrônica de Varredura , Modelos Químicos , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Temperatura
16.
Plant J ; 57(5): 883-94, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18980645

RESUMO

Ectopic gene expression, or the gain-of-function approach, has the advantage that once the function of a gene is known the gene can be transferred to many different plants by transformation. We previously reported a method, called FOX hunting, that involves ectopic expression of Arabidopsis full-length cDNAs in Arabidopsis to systematically generate gain-of-function mutants. This technology is most beneficial for generating a heterologous gene resource for analysis of useful plant gene functions. As an initial model we generated more than 23,000 independent Arabidopsis transgenic lines that expressed rice fl-cDNAs (Rice FOX Arabidopsis lines). The short generation time and rapid and efficient transformation frequency of Arabidopsis enabled the functions of the rice genes to be analyzed rapidly. We screened rice FOX Arabidopsis lines for alterations in morphology, photosynthesis, element accumulation, pigment accumulation, hormone profiles, secondary metabolites, pathogen resistance, salt tolerance, UV signaling, high light tolerance, and heat stress tolerance. Some of the mutant phenotypes displayed by rice FOX Arabidopsis lines resulted from the expression of rice genes that had no homologs in Arabidopsis. This result demonstrated that rice fl-cDNAs could be used to introduce new gene functions in Arabidopsis. Furthermore, these findings showed that rice gene function could be analyzed by employing Arabidopsis as a heterologous host. This technology provides a framework for the analysis of plant gene function in a heterologous host and of plant improvement by using heterologous gene resources.


Assuntos
Perfilação da Expressão Gênica/métodos , Genes de Plantas , Oryza/genética , Arabidopsis/metabolismo , Composição de Bases , DNA Complementar/genética , DNA de Plantas/genética , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Oryza/metabolismo , Fenótipo , Plantas Geneticamente Modificadas/metabolismo
17.
Mol Genet Genomics ; 279(2): 183-92, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18030492

RESUMO

Arabidopsis SUPERMAN (SUP) and members of its family are plant-unique C(2)H(2)-type zinc finger genes that have been implicated in plant growth and development. In this paper, we report that a new SUP-family gene, designated as S A- and A BA-downregulated z inc finger gene (SAZ), is involved in the negative regulation of ABA-mediated signaling. SAZ-GUS fusion proteins were predominantly localized in the nuclei when they were transiently expressed in onion epidermal cells. SAZ transcripts were expressed in the leaves and pistils of very young flower buds. In young seedlings, SAZ expression was downregulated in response to environmental stresses such as drought, salt, ozone and ultraviolet-B irradiation. This downregulation was also observed in response to the phytohormones salicylic acid (SA) and abscisic acid (ABA). SA-responsive downregulation of SAZ was not observed in the npr1-1 mutant, indicating that this regulation is NPR1 dependent. RNAi-mediated knockdown of SAZ (SAZ-kd) resulted in elevated expression of the drought- and ABA-responsive genes rd29B and rab18 under unstressed conditions, and it enhanced the response of these genes to drought and ABA treatment. The expression of several other drought- and/or ABA-responsive genes was not affected by SAZ-kd. Based on these results, we propose that SAZ plays a role in repressing a subset of the ABA-mediated stress-responsive genes in unstressed conditions.


Assuntos
Ácido Abscísico/farmacologia , Proteínas de Arabidopsis/genética , Arabidopsis/efeitos dos fármacos , Fatores de Transcrição/genética , Dedos de Zinco/genética , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genótipo , Glucuronidase/genética , Glucuronidase/metabolismo , Modelos Genéticos , Dados de Sequência Molecular , Fenótipo , Reguladores de Crescimento de Plantas/farmacologia , Plantas Geneticamente Modificadas , Interferência de RNA , RNA de Plantas/genética , RNA de Plantas/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos
18.
Gan To Kagaku Ryoho ; 30(9): 1343-6, 2003 Sep.
Artigo em Japonês | MEDLINE | ID: mdl-14518418

RESUMO

The patient was a 44-year-old woman who had unresectable advanced gastric cancer with peritoneal dissemination and navel metastasis (Sister Mary Joseph metastasis). The lesion was considered surgically incurable, so she was placed on neoadjuvant chemotherapy consisting of biweekly TXL (100 mg/m2/day 1, 15) and TS-1 (80 mg/m2/day 1-14) and 2 weeks rest. Before chemotherapy, she could not eat anything because of poor expansion of the stomach and ascites. After the 1st course she could eat half the volume of a normal meal. The only side effect of this treatment was pigmentation of the skin and alopecia. After the 2nd course, she returned home and chemotherapy was continued on an outpatient basis. After the 5th course, the stenosis of colon and ascites had disappeared in a barium enema and CT scan, respectively. The poor expansion of the stomach was slightly improved. She was considered to have responded and underwent total gastrectomy with D2 and transverse colectomy and splenectomy. There were no clear nodules indicating peritoneal dissemination in the intra-operative findings. Intra-operative cytological examination was negative. The depth of the cancer invasion was limited to the subserosal layer and there was no invasion to the colon histologically. There was no lymph node metastasis, but there were a small number of cancer cells obtained diffusely in the omentum and mesocolon. There was no findings of recurrence 5 months later. Biweekly TXL and TS-1 therapy was thought to be an effective chemotherapy against advanced gastric cancer.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Peritonite/complicações , Neoplasias Gástricas/tratamento farmacológico , Umbigo , Adulto , Quimioterapia Adjuvante , Colectomia , Doenças do Colo/patologia , Doenças do Colo/cirurgia , Constrição Patológica , Esquema de Medicação , Combinação de Medicamentos , Feminino , Gastrectomia , Humanos , Ácido Oxônico/administração & dosagem , Paclitaxel/administração & dosagem , Neoplasias Peritoneais/secundário , Piridinas/administração & dosagem , Esplenectomia , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Tegafur/administração & dosagem
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