Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
1.
Plant Cell ; 35(9): 3604-3625, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37325884

RESUMO

Catalase (CAT) is often phosphorylated and activated by protein kinases to maintain hydrogen peroxide (H2O2) homeostasis and protect cells against stresses, but whether and how CAT is switched off by protein phosphatases remains inconclusive. Here, we identified a manganese (Mn2+)-dependent protein phosphatase, which we named PHOSPHATASE OF CATALASE 1 (PC1), from rice (Oryza sativa L.) that negatively regulates salt and oxidative stress tolerance. PC1 specifically dephosphorylates CatC at Ser-9 to inhibit its tetramerization and thus activity in the peroxisome. PC1 overexpressing lines exhibited hypersensitivity to salt and oxidative stresses with a lower phospho-serine level of CATs. Phosphatase activity and seminal root growth assays indicated that PC1 promotes growth and plays a vital role during the transition from salt stress to normal growth conditions. Our findings demonstrate that PC1 acts as a molecular switch to dephosphorylate and deactivate CatC and negatively regulate H2O2 homeostasis and salt tolerance in rice. Moreover, knockout of PC1 not only improved H2O2-scavenging capacity and salt tolerance but also limited rice grain yield loss under salt stress conditions. Together, these results shed light on the mechanisms that switch off CAT and provide a strategy for breeding highly salt-tolerant rice.


Assuntos
Oryza , Catalase/genética , Catalase/metabolismo , Oryza/metabolismo , Peróxido de Hidrogênio/metabolismo , Proteína Fosfatase 1/metabolismo , Tolerância ao Sal/genética , Homeostase , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
2.
Plant Biotechnol J ; 22(8): 2157-2172, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38506090

RESUMO

Chilling stress has seriously limited the global production and geographical distribution of rice. However, the molecular mechanisms associated with plant responses to chilling stress are less known. In this study, we revealed a member of ß-ketoacyl-ACP synthase I family (KASI), OsKASI-2 which confers chilling tolerance in rice. OsKASI-2 encodes a chloroplast-localized KASI enzyme mainly expressed in the leaves and anthers of rice and strongly induced by chilling stress. Disruption of OsKASI-2 led to decreased KAS enzymatic activity and the levels of unsaturated fatty acids, which impairs degree of unsaturation of membrane lipids, thus increased sensitivity to chilling stress in rice. However, the overexpression of OsKASI-2 significantly improved the chilling tolerance ability in rice. In addition, OsKASI-2 may regulate ROS metabolism in response to chilling stress. Natural variation of OsKASI-2 might result in difference in chilling tolerance between indica and japonica accessions, and Hap1 of OsKASI-2 confers chilling tolerance in rice. Taken together, we suggest OsKASI-2 is critical for regulating degree of unsaturation of membrane lipids and ROS accumulation for maintenance of membrane structural homeostasis under chilling stress, and provide a potential target gene for improving chilling tolerance of rice.


Assuntos
Temperatura Baixa , Regulação da Expressão Gênica de Plantas , Lipídeos de Membrana , Oryza , Proteínas de Plantas , Oryza/genética , Oryza/metabolismo , Oryza/fisiologia , Lipídeos de Membrana/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Estresse Fisiológico , Espécies Reativas de Oxigênio/metabolismo
3.
Mol Breed ; 44(1): 4, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38225950

RESUMO

Improving quality is an essential goal of rice breeding and production. However, rice quality is not solely determined by genotype, but is also influenced by the environment. Phenotype plasticity refers to the ability of a given genotype to produce different phenotypes under different environmental conditions, which can be a representation of the stability of traits. Seven quality traits of 141 hybrid combinations, deriving from the test-crossing of 7 thermosensitive genic male sterile (TGMS) and 25 restorer lines, were evaluated at 5 trial sites with intermittent sowing of three to five in Southern China. In the Yangtze River Basin, it was observed that delaying the sowing time of hybrid rice combinations leads to an improvement in their overall quality. Twelve parents were identified to have lower plasticity general combing ability (GCA) values with increased ability to produce hybrids with a more stable quality. The parents with superior quality tend to exhibit lower GCA values for plasticity. The genome-wide association study (GWAS) identified 13 and 15 quantitative trait loci (QTLs) associated with phenotype plasticity and BLUP measurement, respectively. Notably, seven QTLs simultaneously affected both phenotype plasticity and BLUP measurement. Two cloned rice quality genes, ALK and GL7, may be involved in controlling the plasticity of quality traits in hybrid rice. The direction of the genetic effect of the QTL6 (ALK) on alkali spreading value (ASV) plasticity varies in different cropping environments. This study provides novel insights into the dynamic genetic basis of quality traits in response to different cropping regions, cultivation practices, and changing climates. These findings establish a foundation for precise breeding and production of stable and high-quality rice. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01442-3.

4.
Proc Natl Acad Sci U S A ; 117(9): 4623-4631, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32071222

RESUMO

The successful application of heterosis in hybrid rice has dramatically improved rice productivity, but the genetic mechanism for heterosis in the hybrid rice remains unclear. In this study, we generated two populations of rice F1 hybrids with present-day commercial hybrid parents, genotyped the parents with 50k SNP chip and genome resequencing, and recorded the phenotype of ∼2,000 hybrids at three field trials. By integrating these data with the collected genotypes of ∼4,200 rice landraces and improved varieties that were reported previously, we found that the male and female parents have different levels of genome introgressions from other rice subpopulations, including indica, aus, and japonica, therefore shaping heterotic loci in the hybrids. Among the introgressed exogenous genome, we found that heterotic loci, including Ghd8/DTH8, Gn1a, and IPA1 existed in wild rice, but were significantly divergently selected among the rice subpopulations, suggesting these loci were subject to environmental adaptation. During modern rice hybrid breeding, heterotic loci were further selected by removing loci with negative effect and fixing loci with positive effect and pyramid breeding. Our results provide insight into the genetic basis underlying the heterosis of elite hybrid rice varieties, which could facilitate a better understanding of heterosis and rice hybrid breeding.


Assuntos
Introgressão Genética , Vigor Híbrido , Oryza/genética , Seleção Genética , Genoma de Planta , Melhoramento Vegetal/métodos
5.
BMC Plant Biol ; 22(1): 314, 2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35773646

RESUMO

BACKGROUND: Heterosis is a phenomenon that hybrids show superior performance over their parents. The successful utilization of heterosis has greatly improved rice productivity, but the molecular basis of heterosis remains largely unclear. RESULTS: Here, the transcriptomes of young panicles and leaves of the two widely grown two-line super hybrid rice varieties (Jing-Liang-You-Hua-Zhan (JLYHZ) and Long-Liang-You-Hua-Zhan (LLYHZ)) and their parents were analyzed by RNA-seq. Transcriptome profiling of the hybrids revealed 1,778 ~ 9,404 differentially expressed genes (DEGs) in two tissues, which were identified by comparing with their parents. GO, and KEGG enrichment analysis showed that the pathways significantly enriched in both tissues of two hybrids were all related to yield and resistance, like circadian rhythm (GO:0,007,623), response to water deprivation (GO:0,009,414), and photosynthetic genes (osa00196). Allele-specific expression genes (ASEGs) were also identified in hybrids. The ASEGs were most significantly enriched in ionotropic glutamate receptor signaling pathway, which was hypothesized to be potential amino acid sensors in plants. Moreover, the ASEGs were also differentially expressed between parents. The number of variations in ASEGs is higher than expected, especially for large effect variations. The DEGs and ASEGs are the potential reasons for the formation of heterosis in the two elite super hybrid rice. CONCLUSIONS: Our results provide a comprehensive understanding of the heterosis of two-line super hybrid rice and facilitate the exploitation of heterosis in hybrid rice breeding with high yield heterosis.


Assuntos
Vigor Híbrido , Oryza , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Vigor Híbrido/genética , Hibridização Genética , Oryza/genética , Oryza/metabolismo , Melhoramento Vegetal , Transcriptoma
6.
Plant Biotechnol J ; 20(5): 876-885, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34890109

RESUMO

Rice blast and bacterial blight represent two of major diseases having devastating impact on the yield of rice in most rice-growing countries. Developments of resistant cultivars are the most economic and effective strategy to control these diseases. Here, we used CRISPR/Cas9-mediated gene editing to rapidly install mutations in three known broad-spectrum blast-resistant genes, Bsr-d1, Pi21 and ERF922, in an indica thermosensitive genic male sterile (TGMS) rice line Longke638S (LK638S). We obtained transgene-free homozygous single or triple mutants in T1 generations. While all single and triple mutants showed increased resistance to rice blast compared with wild type, the erf922 mutants displayed the strongest blast resistance similar with triple mutants. Surprisingly, we found that Pi21 or ERF922 single mutants conferred enhanced resistance to most of tested bacterial blight. Both resistances in mutants were attribute to the up-regulation of SA- and JA-pathway associated genes. Moreover, phenotypic analysis of these single mutants in paddy fields revealed that there were no trade-offs between resistances and main agricultural traits. Together, our study provides a rapid and effective way to generate rice varieties with resistance to both rice blast and bacterial blight.


Assuntos
Resistência à Doença , Oryza , Sistemas CRISPR-Cas/genética , Resistência à Doença/genética , Edição de Genes , Oryza/genética , Oryza/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia
7.
Planta ; 253(5): 94, 2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33830376

RESUMO

MAIN CONCLUSION: Using genome-wide SNP association mapping, a total of 77 and 7 loci were identified for rice bacterial blight and bacterial leaf streak resistance, respectively, which may facilitate rice resistance improvement. Bacterial blight (BB) and bacterial leaf streak (BLS) caused by Gram-negative bacteria Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc), respectively, are two economically important diseases negatively affecting rice production. To mine new sources of resistance, a set of rice germplasm collection consisting of 895 re-sequenced accessions from the 3000 Rice Genomes Project (3 K RGP) were screened for BB and BLS resistance under field conditions. Higher levels of BB resistance were observed in aus/boro subgroup, whereas the japonica, temperate japonica and tropical japonica subgroups possessed comparatively high levels of resistance to BLS. A genome-wide association study (GWAS) mined 77 genomic loci significantly associated with BB and 7 with BLS resistance. The phenotypic variance (R2) explained by these loci ranged from 0.4 to 30.2%. Among the loci, 7 for BB resistance were co-localized with known BB resistance genes and one for BLS resistance overlapped with a previously reported BLS resistance QTL. A search for the candidates in other novel loci revealed several defense-related genes that may be involved in resistance to BB and BLS. High levels of phenotypic resistance to BB or BLS could be attributed to the accumulation of the resistance (R) alleles at the associated loci, indicating their potential value in rice resistance breeding via gene pyramiding. The GWAS analysis validated the known genes underlying BB and BLS resistance and identified novel loci that could enrich the current resistance gene pool. The resources with strong resistance and significant SNPs identified in this study are potentially useful in breeding for BB and BLS resistance.


Assuntos
Resistência à Doença/genética , Estudo de Associação Genômica Ampla , Oryza/genética , Oryza/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Xanthomonas/patogenicidade , Genes de Plantas/genética , Humanos , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único/genética
8.
J Exp Bot ; 72(20): 6963-6976, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34283218

RESUMO

Heterosis of grain yield is closely associated with heading date in crops. Gene combinations of the major heading date genes Ghd7, Ghd8, and Hd1 play important roles in enhancing grain yield and adaptation to ecological regions in rice. However, the predominant three-gene combinations for a specific ecological region remain unclear in both three-line and two-line hybrids. In this study, we sequenced these three genes of 50 cytoplasmic male sterile/maintainer lines, 31 photo-thermo-sensitive genic male sterile lines, and 109 restorer lines. Sequence analysis showed that hybrids carrying strong functional alleles of Ghd7 and Hd1 and non-functional Ghd8 are predominant in three-line hybrids and are recommended for rice production in the subtropics around 30°N/S. Hybrids carrying strong functional Ghd7 and Ghd8 and non-functional Hd1 are predominant in two-line hybrids and are recommended for low latitude areas around 23.5°N/S rich in photothermal resources. Hybrids carrying strong functional Ghd7 and Ghd8 and functional Hd1 were not identified in commercial hybrids in the middle and lower reaches of the Yangtze River, but they have high yield potential in tropical regions because they have the strongest photoperiod sensitivity. Based on these findings, two genic sterile lines, Xiangling 628S and C815S, whose hybrids often head very late, were diagnosed with these three genes, and Hd1 was targeted to be knocked out in Xiangling 628S and replaced with hd1 in C815S. The hybrids developed from both modified sterile lines in turn had appropriate heading dates and significantly improved grain yield. This study provides new insights for breeding design to develop hybrids for various regions.


Assuntos
Oryza , Flores/metabolismo , Regulação da Expressão Gênica de Plantas , Vigor Híbrido/genética , Oryza/genética , Oryza/metabolismo , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
9.
Plant Cell ; 30(5): 1100-1118, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29581216

RESUMO

Salt stress can significantly affect plant growth and agricultural productivity. Receptor-like kinases (RLKs) are believed to play essential roles in plant growth, development, and responses to abiotic stresses. Here, we identify a receptor-like cytoplasmic kinase, salt tolerance receptor-like cytoplasmic kinase 1 (STRK1), from rice (Oryza sativa) that positively regulates salt and oxidative stress tolerance. Our results show that STRK1 anchors and interacts with CatC at the plasma membrane via palmitoylation. CatC is phosphorylated mainly at Tyr-210 and is activated by STRK1. The phosphorylation mimic form CatCY210D exhibits higher catalase activity both in vitro and in planta, and salt stress enhances STRK1-mediated tyrosine phosphorylation on CatC. Compared with wild-type plants, STRK1-overexpressing plants exhibited higher catalase activity and lower accumulation of H2O2 as well as higher tolerance to salt and oxidative stress. Our findings demonstrate that STRK1 improves salt and oxidative tolerance by phosphorylating and activating CatC and thereby regulating H2O2 homeostasis. Moreover, overexpression of STRK1 in rice not only improved growth at the seedling stage but also markedly limited the grain yield loss under salt stress conditions. Together, these results offer an opportunity to improve rice grain yield under salt stress.


Assuntos
Oryza/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Oryza/genética , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Fosforilação , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Estresse Fisiológico
10.
Ecotoxicol Environ Saf ; 222: 112491, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34237643

RESUMO

The toxic effects of different nanoparticles (NPs) have been reported to be quite different. The present study exposed Daphnia pulex to undissociated TiO2 NPs and SiO2 NPs, and dissociated ZnO NPs. The acute toxicity of the three oxide NPs and their influence on D. pulex molting, as well as the expressions of genes related to molting, energy metabolism and genetic material expression were compared. The results showed that the toxicities of TiO2 NPs and SiO2 NPs to D. pulex were weaker than ZnO NPs. During the exposure period, agglomerates of undissociated TiO2 NPs and SiO2 NPs influenced movements of D. pulex, and induced their molting after attaching to the body surface. Meanwhile, gene expressions of molting (eip) and energy metabolism (scot and idh) were up-regulated. Therefore, we inferred that the adhering to the surface of daphnids, promoting their molting and improving their energy metabolism may be parts of the toxicity mechanisms of undissociated NPs to D. pulex. On the contrary, dissociated ZnO NPs inhibited molting and gene expressions of eip, scot and idh, which showed a similar trend as bulk ZnO and ZnSO4·7H2O under the low-dose exposure condition. This indicates that the toxic effects of dissociated ZnO NPs were primarily caused by released Zn ions. The results provided direct evidence about the effect of nanoparticles on molting and revealed that the toxicity mechanisms of dissociated NPs were different from undissociated NPs.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Óxido de Zinco , Animais , Daphnia/genética , Nanopartículas Metálicas/toxicidade , Muda , Nanopartículas/toxicidade , Dióxido de Silício , Titânio , Óxido de Zinco/toxicidade
11.
Pestic Biochem Physiol ; 160: 58-69, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31519258

RESUMO

Microbial antagonists and their bioactive metabolites provide one of the best alternatives to chemical pesticides to control crop disease for sustainable agriculture and global food security. The rice endophyte Streptomyces hygroscopicus OsiSh-2, with remarkable antagonistic activity towards the rice blast fungus Magnaporthe oryzae, was reported in our previous study. The present study deciphered the possible direct interaction mode of OsiSh-2 against M. oryzae. An in vitro antibiotic assay for OsiSh-2 culture filtrate revealed strong suppression of mycelial growth, conidial germination and appressorial formation of M. oryzae. Meanwhile, severe morphological and internal abnormalities in M. oryzae hyphae were observed under a scanning electron microscope and transmission electron microscope. Foliar treatment of rice seedlings by OsiSh-2 culture filtrate in the greenhouse and in the field showed 23.5% and 28.3% disease reduction, respectively. Correspondingly, OsiSh-2 culture filtrate could induce disorganized chitin deposition in the cell wall and lowered ergosterol content in the cell membrane of M. oryzae. Additionally, cell wall integrity pathway activation, large cell electrolytes release, reactive oxygen species accumulation and tricarboxylic acid cycle-related enzyme activity changes were found in M. oryzae. All these results suggested that the direct antagonistic activity of OsiSh-2 against M. oryzae may be attributed to damaging the integrity of the cell wall and membrane and disrupting mitochondrial function in the pathogen.


Assuntos
Antifúngicos/farmacologia , Endófitos/fisiologia , Magnaporthe/efeitos dos fármacos , Oryza/microbiologia , Controle Biológico de Vetores , Streptomyces/química
12.
J Integr Plant Biol ; 60(2): 85-88, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28059483

RESUMO

NADP(H)-dependent glutamate dehydrogenases (GDH) in lower organisms have stronger ammonium affinity than those in higher plants. Here we report that transgenic rice overexpressing the EcGDH from Eurotium cheralieri exhibited significantly enhanced aminating activities. Hydroponic and field tests showed that nitrogen assimilation efficiency and grain yields were markedly increased in these transgenic plants, especially at the low nitrogen conditions. These results suggest that EcGDH may have potential to be used to improve nitrogen assimilation and grain yield in rice.


Assuntos
Expressão Ectópica do Gene , Eurotium/enzimologia , Glutamato Desidrogenase/genética , Nitrogênio/metabolismo , Oryza/metabolismo , Sementes/crescimento & desenvolvimento , Glutamato Desidrogenase/metabolismo , Nitrogênio/farmacologia , Oryza/efeitos dos fármacos , Oryza/genética , Plantas Geneticamente Modificadas , Plântula/efeitos dos fármacos , Plântula/genética , Sementes/efeitos dos fármacos
14.
Plant Physiol ; 171(1): 334-43, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26945049

RESUMO

The molecular mechanisms underlying photoperiod or temperature control of flowering time have been recently elucidated, but how plants regulate flowering time in response to other external factors, such as water availability, remains poorly understood. Using a large-scale Hybrid Transcription Factor approach, we identified a bZIP transcriptional factor, O. sativa ABA responsive element binding factor 1 (OsABF1), which acts as a suppressor of floral transition in a photoperiod-independent manner. Simultaneous knockdown of both OsABF1 and its closest homologous gene, OsbZIP40, in rice (Oryza sativa) by RNA interference results in a significantly earlier flowering phenotype. Molecular and genetic analyses demonstrate that a drought regime enhances expression of the OsABF1 gene, which indirectly suppresses expression of the Early heading date 1 (Ehd1) gene that encodes a key activator of rice flowering. Furthermore, we identified a drought-inducible gene named OsWRKY104 that is under the direct regulation of OsABF1 Overexpression of OsWRKY104 can suppress Ehd1 expression and confers a later flowering phenotype in rice. Together, these findings reveal a novel pathway by which rice modulates heading date in response to the change of ambient water availability.


Assuntos
Secas , Oryza/fisiologia , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Oryza/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Interferência de RNA , Fatores de Transcrição/genética
15.
J Sci Food Agric ; 97(4): 1149-1157, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27293085

RESUMO

BACKGROUND: Biocontrol is a promising strategy in the control of rice blast disease. In the present study, we isolated and characterized a novel antagonist to the pathogen Magnaporthe oryzae from rice endophytic actinomycetes. RESULTS: Out of 482 endophytic actinomycetes isolated from rice blast infected and healthy rice, Streptomyces endus OsiSh-2 exhibited remarkable in vitro antagonistic activity. Scanning electron microscopy observations of M. oryzae treated by OsiSh-2 revealed significant morphological alterations in hyphae. In 2-year field tests, the spraying of OsiSh-2 spore solution (107 spores mL-1 ) is capable of reducing rice blast disease severity by 59.64%. In addition, a fermentation broth of OsiSh-2 and its cell-free filtrates could inhibit the growth of M. oryzae, suggesting the presence of active enzymes and secondary metabolites. OsiSh-2 tested positive for polyketide synthase-I and nonribosomal peptide synthetase genes and can produce cellulase, protease, gelatinase, siderophore, indole-3-acetic acid and 1-amino-cyclopropane-1-carboxylate deaminase. A preliminary separation indicated that the methanol extract of OsiSh-2 could suppress the growth of pathogens. The major active component was identified as nigericin. CONCLUSION: Endophytic S. endus OsiSh-2 has potential as a biocontrol agent against rice blast in agriculture. © 2016 Society of Chemical Industry.


Assuntos
Proteínas de Bactérias/metabolismo , Agentes de Controle Biológico/farmacologia , Fungicidas Industriais/farmacologia , Magnaporthe/efeitos dos fármacos , Oryza/microbiologia , Doenças das Plantas/microbiologia , Streptomyces , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Agentes de Controle Biológico/química , Meios de Cultura , Endófitos/química , Endófitos/enzimologia , Endófitos/isolamento & purificação , Fermentação , Filtração , Fungicidas Industriais/química , Genes Bacterianos , Hifas , Ácidos Indolacéticos/metabolismo , Magnaporthe/patogenicidade , Nigericina/análise , Nigericina/farmacologia , Sideróforos/metabolismo , Esporos Bacterianos , Streptomyces/química , Streptomyces/enzimologia , Streptomyces/isolamento & purificação
16.
Planta ; 241(3): 727-40, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25486886

RESUMO

MAIN CONCLUSION: Heterologous expression of a fungal NADP(H)-GDH gene ( MgGDH ) from Magnaporthe grisea can improve dehydration stress tolerance in rice by preventing toxic accumulation of ammonium. Glutamate dehydrogenase (GDH; EC 1.4.1.2 and EC 1.4.1.4) may act as a stress-responsive enzyme in detoxification of high intracellular ammonia and production of glutamate for proline synthesis under stress conditions. In present study, a fungal NADP(H)-GDH gene (MgGDH) from Magnaporthe grisea was over-expressed in rice (Oryza sativa L. cv. 'kitaake'), and the transgenic plants showed the improvement of tolerance to dehydration stress. The kinetic analysis showed that His-TF-MgGDH preferentially utilizes ammonium to produce L-glutamate. Moreover, the affinity of His-TF-MgGDH for ammonium was dramatically higher than that of His-TF-OsGDH for ammonium. Over-expressing MgGDH transgenic rice plants showed lower water-loss rate and higher completely close stomata than the wild-type plants under dehydration stress conditions. In transgenic plants, the NADP(H)-GDH activities were markedly higher than those in wild-type plants and the amination activity was significantly higher than the deamination activity. Compared with wild-type plants, the transgenic plants accumulated much less NH4 (+) but higher amounts of glutamate, proline and soluble sugar under dehydration stress conditions. These results indicate that heterologous expression of MgGDH can prevent toxic accumulation of ammonium and in return improve dehydration stress tolerance in rice.


Assuntos
Desidrogenase de Glutamato (NADP+)/genética , Magnaporthe/genética , Oryza/fisiologia , Estresse Fisiológico , Água/fisiologia , Adaptação Fisiológica , Aminação , Compostos de Amônio/metabolismo , Metabolismo dos Carboidratos , Desidrogenase de Glutamato (NADP+)/metabolismo , Ácido Glutâmico/metabolismo , Cinética , Plantas Geneticamente Modificadas , Prolina/metabolismo , Proteínas Recombinantes/metabolismo
17.
Mol Biol Rep ; 41(6): 3683-93, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24557889

RESUMO

The full-length cDNA encoding a glutamate dehydrogenase (GDH) which catalyzes the reaction of reductive amination of α-oxoglutarate (α-OG) to glutamate (the anabolic activity) and the reverse reaction of oxidative deamination of glutamate (the catabolic activity) was isolated from Sclerotinia sclerotiorum, we designated it as SsGDH. Bioinformatics analysis revealed that SsGDH had a typical GDH spatial structure and extensive homology with other fungal or bacteria GDHs. To evaluate its function in rice, rice (Oryza sativa L. cv. 'kitaake') was transformed with SsGDH in a binary vector construct by Agrobacterium-mediated transformation. Transgenic rice plants showed that transcripts and proteins of SsGDH accumulated at higher levels and GDH enzymatic activity was obviously higher in transgenic rice plants compared with the non-transformant rice plants (CK), though phenotype including plant height, fresh weight and dry weight became slightly weaker compared with CK under 50, 500 and 5,000 µM nitrogen gradient nutrient solution treatment (NH4NO3 as a nitrogen source) after introducing SsGDH into rice. For enzymatic activity assay in vitro, recombinant His6-SsGDH protein was expressed in Escherichia coli BL21 (DE3) and purified by Ni-NTA agarose. Results suggested that recombinant His6-SsGDH protein had GDH activity using ammonium, α-OG, and L-glutamate separately as a substrate at two different concentrations, especially the affinity for ammonium was very high, and its Km value was only 0.28 ± 0.03 mM, indicating that SsGDH can assimilate more ammonium into rice. According to previous reports, transgenic plants expressing fungal or bacteria GDHs might show improved herbicide resistance. Basta resistance test showed that SsGDH expression in rice can significantly enhanced their tolerance to Basta than CK. In conclusion, our results may provide some clues for further investigation on nitrogen utilization via introducing exogenous GDHs from lower organisms into rice.


Assuntos
Glutamato Desidrogenase/biossíntese , Glutamato Desidrogenase/genética , Oryza/genética , Ascomicetos , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Glutamato Desidrogenase/química , Nitrogênio/metabolismo , Plantas Geneticamente Modificadas/genética , Homologia de Sequência de Aminoácidos
18.
Sci Total Environ ; 900: 165821, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37506919

RESUMO

Human exposure to arsenic via drinking water is one of globally concerned health issues. Oxidative stress is regarded as the denominator of arsenic-inducing toxicities. Therefore, to identify intracellular sources of reactive oxygen species (ROS) could be essential for addressing the detrimental effects of arsenite (iAsIII). In this study, the contributions of different pathways to ROS formation in iAsIII-treated human normal liver (L-02) cells were quantitatively assessed, and then concomitant oxidative impairs were evaluated using metabolomics and lipidomics approaches. Following iAsIII treatment, NADPH oxidase (NOX) activity and expression levels of p47phox and p67phox were upregulated, and NOX-derived ROS contributed to almost 60.0 % of the total ROS. Moreover, iAsIII also induced mitochondrial superoxide anion and impaired mitochondrial respiratory function of L-02 cells with a decreasing ATP production. The inhibition of NOX activity significantly rescued mitochondrial membrane potential in iAsIII-treated L-02 cells. Purine and glycerophospholipids metabolisms in L-02 cells were disrupted by iAsIII, which might be used to represent DNA and plasma membrane damages, respectively. Our study supported that NOX could be the primary pathway of ROS overproduction and revealed the potential mechanisms of iAsIII toxicity related to oxidative stress.


Assuntos
Arsênio , Arsenitos , Humanos , Espécies Reativas de Oxigênio/metabolismo , Arsenitos/toxicidade , Fígado/metabolismo , Membrana Celular/metabolismo , DNA
19.
Rice (N Y) ; 16(1): 21, 2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-37084146

RESUMO

BACKGROUND: Soil salinization is a major abiotic environmental stress factor threatening crop production throughout the world. Salt stress drastically affects the growth, development, and grain yield of rice (Oryza sativa L.), and the improvement of rice tolerance to salt stress is a desirable approach for meeting increasing food demand. Receptor-like cytoplasmic kinases (RLCKs) play essential roles in plant growth, development and responses to environmental stresses. However, little is known about their functions in salt stress. Previous reports have demonstrated that overexpression of an RLCK gene SALT TOLERANCE KINASE (STK) enhances salt tolerance in rice, and that STK may regulate the expression of GST (Glutathione S-transferase) genes. RESULTS: The expression of STK was rapidly induced by ABA. STK was highest expressed in the stem at the heading stage. STK was localized at the plasma membrane. Overexpression of STK in rice increased tolerance to salt stress and oxidative stress by increasing ROS scavenging ability and ABA sensitivity. In contrast, CRISPR/Cas9-mediated knockout of STK increased the sensitivity of rice to salt stress and oxidative stress. Transcriptome sequencing analysis suggested that STK increased the expression of GST genes (LOC_Os03g17480, LOC_Os10g38140 and LOC_Os10g38710) under salt stress. Reverse transcription quantitative PCR (RT-qPCR) suggested that four stress-related genes may be regulated by STK including OsABAR1, Os3BGlu6, OSBZ8 and OsSIK1. CONCLUSIONS: These findings suggest that STK plays a positive regulatory role in salt stress tolerance by inducing antioxidant defense and associated with the ABA signaling pathway in rice.

20.
Nat Commun ; 14(1): 4441, 2023 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-37488129

RESUMO

Recurrent heat stress and pathogen invasion seriously threaten crop production, and abiotic stress often antagonizes biotic stress response against pathogens. However, the molecular mechanisms of trade-offs between thermotolerance and defense remain obscure. Here, we identify a rice thermo-sensitive mutant that displays a defect in floret development under high temperature with a mutation in SUPPRESSOR OF GENE SILENCING 3a (OsSGS3a). OsSGS3a interacts with its homolog OsSGS3b and modulates the biogenesis of trans-acting small interfering RNA (tasiRNA) targeting AUXIN RESPONSE FACTORS (ARFs). We find that OsSGS3a/b positively, while OsARF3a/b and OsARF3la/lb negatively modulate thermotolerance. Moreover, OsSGS3a negatively, while OsARF3a/b and OsARF3la/lb positively regulate disease resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo) and the fungal pathogen Magnaporthe oryzae (M. oryzae). Taken together, our study uncovers a previously unknown trade-off mechanism that regulates distinct immunity and thermotolerance through the OsSGS3-tasiRNA-OsARF3 module, highlighting the regulation of abiotic-biotic stress response trade-off in plants.


Assuntos
Oryza , Termotolerância , Resistência à Doença , RNA Interferente Pequeno
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa