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1.
Ecotoxicol Environ Saf ; 202: 110916, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800251

RESUMO

Selenium (Se) at low concentration is considered benefit element to plants. The range between optimal and toxic concentration of Se is narrow and varies among plant species. This study aimed to evaluate the phenotypic, physiological and biochemical responses of four rice genotypes (BRS Esmeralda, BRSMG Relâmpago, BRS Bonança and Bico Ganga) grown hydroponically treated with sodium selenate (1.5 mM L-1). Selenium treated plants showed a dramatically decrease of soluble proteins, chlorophylls, and carotenoids concentration, resulting in the visual symptoms of toxicity characterized as leaf chlorosis and necrosis. Selenium toxicity caused a decrease on shoot and root dry weight of rice plants. Excess Se increased the oxidative stress monitored by the levels of hydrogen peroxide and lipid peroxidation. The enzymatic antioxidant system (catalase, superoxide dismutase, and ascorbate peroxidase) increased in response to Se supply. Interestingly, primary metabolism compounds such as sucrose, total sugars, nitrate, ammonia and amino acids increased in Se-treated plants. The increase in these metabolites may indicate a defense mechanism for the osmotic readjustment of rice plants to mitigate the toxicity caused by Se. However, these metabolites were not effective to minimize the damages on phenotypic traits such as leaf chlorosis and reduced shoot and root dry weight in response to excess Se. Increased sugars profile combined with antioxidant enzymes activities can be an effective biomarkers to indicate stress induced by Se in rice plants. This study shows the physiological attributes that must be taken into account for success in the sustainable cultivation of rice in environments containing excess Se.


Assuntos
Oryza/fisiologia , Selênio/toxicidade , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Hidroponia , Peroxidação de Lipídeos , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/metabolismo , Ácido Selênico/metabolismo , Superóxido Dismutase/metabolismo
2.
Bull Environ Contam Toxicol ; 105(3): 428-432, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32740744

RESUMO

The accumulation of Cd and Pb in rice grains poses a potential threat to human health, which is a subject of increasing concern across the globe. We examined the effect that foliar spraying of Zn-ethylenediaminetetraacetate (Zn-EDTA) (0.3% and 0.5% w/v) during the early-grain filling stage has on rice grain yield and Cd, Pb, Zn and Fe contents in rice tissues via a field experiment. The grain yield significantly decreased with the foliar application of 0.5% Zn-EDTA. In rice grain, foliar spraying of 0.5% Zn-EDTA significantly decreased the Cd and Pb contents, but increased the Zn and Fe contents. The main reasons for the decrease in the Cd and Pb content in grain were the inhibition of Cd and Pb by roots and the increased Fe content in grain via Zn-EDTA application. The foliar spraying of Zn-EDTA decreased the grain yield and Cd and Pb contents, while increased the Zn and Fe contents in grains.


Assuntos
Cádmio/análise , Ácido Edético/química , Chumbo/análise , Oryza/fisiologia , Poluentes do Solo/análise , Grão Comestível/química , Humanos , Oryza/efeitos dos fármacos , Folhas de Planta/química , Raízes de Plantas/química , Solo , Zinco/análise
3.
PLoS One ; 15(8): e0237334, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776991

RESUMO

We studied the correlation of synonymous codon usage (SCU) on gene expression levels under drought stress in rice. Sixty genes related to drought stress (with high, intermediate and low expression) were selected from rice meta-analysis data and various codon usage indices such as the effective number of codon usage (ENC), codon adaptation index (CAI) and relative synonymous codon usage (RSCU) were calculated. We found that in genes highly expressing under drought 1) GC content was higher, 2) ENC value was lower, 3) the preferred codons of some amino acids changed and 4) the RSCU ratio of GC-end codons relative to AT-end codons for 18 amino acids increased significantly compared with those in other genes. We introduce ARSCU as the Average ratio of RSCUs of GC-end codons to AT-end codons in each gene that could significantly separate high-expression genes under drought from low-expression genes. ARSCU is calculated using the program ARSCU-Calculator developed by our group to help predicting expression level of rice genes under drought. An index above ARSCU threshold is expected to indicate that the gene under study may belong to the "high expression group under drought". This information may be applied for codon optimization of genes for rice genetic engineering. To validate these findings, we further used 60 other genes (randomly selected subset of 43233 genes studied for their response to drought stress). ARSCU value was able to predict the level of expression at 88.33% of the cases. Using third set of 60 genes selected amongst high expressing genes not related to drought, only 31.65% of the genes showed ARSCU value of higher than the set threshold. This indicates that the phenomenon we described in this report may be unique for drought related genes. To justify the observed correlation between CUB and high expressing genes under drought, possible role of tRNA post transcriptional modification and tRFs was hypothesized as possible underlying biological mechanism.


Assuntos
Aclimatação/genética , Secas , Regulação da Expressão Gênica de Plantas/fisiologia , Genes de Plantas/genética , Oryza/fisiologia , Composição de Bases , Uso do Códon , Simulação por Computador , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla
4.
PLoS One ; 15(8): e0238173, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853293

RESUMO

Damage to grasses and cereals by phloem-feeding herbivores is manifest as nutrient and chlorophyll loss, desiccation, and a gradual decline in host vigour. Chlorophyll loss in particular leads to a succession of colour changes before eventual host death. Depending on the attacking herbivore species, colour changes can be difficult to detect with the human eye. This study used digital images to examine colour changes of rice seedlings during feeding by the brown planthopper, Nilaparvata lugens (Stål) and whitebacked planthopper, Sogatella furcifera (Horváth). Values for red (580 nm), green (540 nm) and blue (550 nm) reflectance for 39 rice varieties during seedling seed-box tests were derived from images captured with a digital camera. Red and blue reflectance gradually increased as herbivore damage progressed until final plant death. Red reflectance was greater from plants attacked by the brown planthopper than plants attacked by the whitebacked planthopper, which had proportionately more green and blue reflectance, indicating distinct impacts by the two planthoppers on their hosts. Analysis of digital images was used to discriminate variety responses to the two planthoppers. Ordination methods based on red-green-blue reflectance and vegetation indices such as the Green Leaf Index (GLI) that included blue reflectance were more successful than two-colour indices or indices based on hue, saturation and brightness in discriminating between damage responses among varieties. We make recommendations to advance seed-box screening methods for cereal resistance to phloem feeders and demonstrate how images from digital cameras can be used to improve the quality of data captured during high-throughput phenotyping.


Assuntos
Oryza/fisiologia , Oryza/parasitologia , Plântula/fisiologia , Plântula/parasitologia , Animais , Clorofila/metabolismo , Hemípteros/patogenicidade , Oryza/metabolismo , Fenótipo , Floema/metabolismo , Floema/parasitologia , Floema/fisiologia , Plântula/metabolismo
5.
PLoS One ; 15(7): e0227785, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32673318

RESUMO

A panel of 60 genotypes comprising New Plant Types (NPTs) along with indica, tropical and temperate japonica genotypes was phenotypically evaluated for four seasons in irrigated situation for grain yield per se and component traits. Twenty NPT genotypes were found promising with an average grain yield varying from 5.45 to 8.8 t/ha. A total of 85 SSR markers were used in the study to identify QTLs associated with grain yield per se and related traits. Sixty-six (77.65%) markers were found to be polymorphic. The PIC values varied from 0.516 to 0.92 with an average of 0.704. A moderate level of genetic diversity (0.39) was detected among genotypes. Variation to the tune of 8% within genotypes, 68% among the genotypes within the population and 24% among the populations were observed (AMOVA). This information may help in identification of potential parents for development of transgressive segregants with very high yield. The association analysis using GLM and MLM models led to the identification of 30 and 10 SSR markers associated with 70 and 16 QTLs, respectively. Thirty novel QTLs linked with 16 SSRs were identified to be associated with eleven traits, namely tiller number (qTL-6.1, qTL-11.1, qTL-4.1), panicle length (qPL-1.1, qPL-5.1, qPL-7.1, qPL-8.1), flag leaf length (qFLL-8.1, qFLL-9.1), flag leaf width (qFLW-6.2, qFLW-5.1, qFLW-8.1, qFLW-7.1), total no. of grains (qTG-2.2, qTG-a7.1), thousand-grain weight (qTGW-a1.1, qTGW-a9.2, qTGW-5.1, qTGW-8.1), fertile grains (qFG-7.1), seed length-breadth ratio (qSlb-3.1), plant height (qPHT-6.1, qPHT-9.1), days to 50% flowering (qFD-1.1) and grain yield per se (qYLD-5.1, qYLD-6.1a, qYLD-11.1).Some of the SSRs were co-localized with more than two traits. The highest co-localization was identified with RM5709 linked to nine traits, followed by RM297 with five traits. Similarly, RM5575, RM204, RM168, RM112, RM26499 and RM22899 were also recorded to be co-localized with more than one trait and could be rated as important for marker-assisted backcross breeding programs, for pyramiding of these QTLs for important yield traits, to produce new-generation rice for prospective increment in yield potentiality and breaking yield ceiling.


Assuntos
Oryza/genética , Locos de Características Quantitativas , Grão Comestível/genética , Variação Genética , Genótipo , Repetições de Microssatélites/genética , Oryza/fisiologia , Fenótipo , Folhas de Planta/genética , Folhas de Planta/fisiologia , Análise de Componente Principal
6.
Artigo em Inglês | MEDLINE | ID: mdl-32594380

RESUMO

Influence of arsenic (As) in As tolerant and sensitive rice genotypes based chloroplastic pigments, leaf gas exchange attributes and their influence on carbohydrate metabolism were investigated in the present study. As retards growth of crop plants and increase several health ailments by contaminating food chain. Photosynthetic inhibition is known to be the prime target of As toxicity due to over-production of ROS. Hydroponically grown rice seedlings of twelve cultivars were exposed to 25, 50, and 75 µM arsenate (AsV) that exerted negative impact on plastidial pigments content and resulted into inhibition of Hill activity. Internal CO2 concentration lowered gradually due to interference of As with stomatal conductance and transpiration rate that subsequently led to drop in net photosynthesis. Twelve contrasting rice genotypes responded differentially to As(V) stress. Present study evaluated As tolerant and sensitive rice cultivars with respect to As(V) imposed alterations in pigments content, photosynthetic attributes along with sugar metabolism. Starch contents, the principle carbohydrate storage declined differentially among As(V) stressed test cultivars, being more pronounced in cvs. Swarnadhan, Tulaipanji, Pusa basmati, Badshabhog, Tulsibhog and IR-20 compared to cvs. Bhutmuri, Kumargore, Binni, Vijaya, TN-1 and IR-64. Therefore, the six former cultivars tried to adapt defensive mechanisms by accumulating higher levels of reducing and non-reducing sugars to carry out basal metabolism to withstand As(V) induced alterations in photosynthesis. This study could help to screen As tolerant and sensitive rice genotypes based on their photosynthetic efficiency in As polluted agricultural fields to reduce As contamination assisted ecotoxicological risk.


Assuntos
Arseniatos/efeitos adversos , Metabolismo dos Carboidratos/efeitos dos fármacos , Oryza/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Poluentes do Solo/efeitos adversos , Genótipo , Oryza/genética , Oryza/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Estresse Fisiológico
7.
Plant Mol Biol ; 103(4-5): 545-560, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32504260

RESUMO

KEY MESSAGE: OsGTγ-2, a trihelix transcription factor, is a positive regulator of rice responses to salt stress by regulating the expression of ion transporters. Salinity stress seriously restricts rice growth and yield. Trihelix transcription factors (GT factors) specifically bind to GT elements and play a diverse role in plant morphological development and responses to abiotic stresses. In our previous study, we found that the GT-1 element (GAAAAA) is a key element in the salinity-induced OsRAV2 promoter. Here, we identified a rice OsGTγ family member, OsGTγ-2, which directly interacted with the GT-1 element in the OsRAV2 promoter. OsGTγ-2 specifically targeted the nucleus, was mainly expressed in roots, sheathes, stems and seeds, and was induced by salinity, osmotic and oxidative stresses and abscisic acid (ABA). The seed germination rate, seedling growth and survival rate under salinity stress was improved in OsGTγ-2 overexpressing lines (PZmUbi::OsGTγ-2). In contrast, CRISPR/Cas9-mediated OsGTγ-2 knockout lines (osgtγ-2) showed salt-hypersensitive phenotypes. In response to salt stress, different Na+ and K+ acclamation patterns were observed in PZmUbi::OsGTγ-2 lines and osgtγ-2 plants were observed. The molecular mechanism of OsGTγ-2 in rice salt adaptation was also investigated. Several major genes responsible for ion transporting, such as the OsHKT2; 1, OsHKT1; 3 and OsNHX1 were transcriptionally regulated by OsGTγ-2. A subsequent yeast one-hybrid assay and EMSA indicated that OsGTγ-2 directly interacted with the promoters of OsHKT2; 1, OsNHX1 and OsHKT1; 3. Taken together, these results suggest that OsGTγ-2 is an important positive regulator involved in rice responses to salt stress and suggest a potential role for OsGTγ-2 in regulating salinity adaptation in rice.


Assuntos
Aclimatação/fisiologia , Proteínas de Ligação a DNA/metabolismo , Oryza/fisiologia , Estresse Salino/fisiologia , Tolerância ao Sal/genética , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Aclimatação/genética , Adaptação Fisiológica , Sistemas CRISPR-Cas , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/crescimento & desenvolvimento , Desenvolvimento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Salinidade , Plântula/genética , Sementes/metabolismo , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Estresse Fisiológico/genética , Simportadores/metabolismo , Fatores de Transcrição/genética
8.
PLoS One ; 15(6): e0233735, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497128

RESUMO

Many fertilization models have been created to scientifically determine the amount of fertilization. With the same purpose, we constructed a nitrogen (N) application model, the leaf value model, which can make N fertilizer decisions in a timely, fast and nondestructive manner during rice planting. However, only one area (A1, Jiuzhou Town, Xixiu District, Guizhou Province) and one cultivar (Qyou6) were involved in the construction of the leaf value model. Its stability and applicability could not be well evaluated. Thus, we chose another area (A2, Jiuzhou Town, Huangping County, Guizhou Province) in Guizhou Province and carried out the experiment by using four cultivars (Nie5you5399, Qyou6, Yixiangyou2115 and Zhongzheyou8) for the leaf value model construction. Compared with the average value of apparent total N uptake (Nz) obtained in 2 years in the A1 area, that in the Qyou6 leaf value model in the A2 area increased by 12%, reaching 635.72 kg ha-1, whereas the corresponding target yield changed slightly, reaching 10,999.90 kg ha-1. Simultaneously, the linear relationship between several good SPAD value-derived indexes (Ys) and apparent N supply of the field (Nx) was still significant or extremely significant in the Qyou6 leaf value model. Compared with the A1 area, it slightly differed, and the R2 of SPADL1 was higher than that of SPADL3×L4/mean. In the leaf value model of the other three cultivars, the relationship between yield and Nx and that between Ys and Nx were significant or extremely significant. The Nz of Yixiangyou2115 and Zhongzheyou8 (618.33 and 617.76 kg ha-1) were close to that of Qyou6 and the corresponding target yields were 10313.36 and 10301.99 kg ha-1, respectively. The Nz and target yield of Nie5you5399 were lowest at 546.63 and 10680.24 kg ha-1, respectively. In general, this study showed that relationships used in the construction of leaf value model had certain stability and applicability to difference areas and cultivars. The leaf value model can be considered in N fertilizer decision-making of rice planting management.


Assuntos
Fertilizantes , Modelos Biológicos , Nitrogênio/administração & dosagem , Oryza/fisiologia , Folhas de Planta/fisiologia , Clorofila/análise , Produção Agrícola/métodos , Oryza/anatomia & histologia , Oryza/química , Folhas de Planta/química , Solo/química
9.
Chemosphere ; 259: 127258, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32585458

RESUMO

This is the first study to investigate the reduction mechanism of Tl (III) to Tl(I) in the presence of plants, especially rice. Smaller plant density could effectively reduce the content of organic acids in the hydroponic system to keep the stability of Tl(III). As the plant density was reduced from 40 seedlings to 10 seedlings in 100 mL Tl(III) solution, the content of oxalate was declined to one-third of the original, and the ratio of Tl(III)/total Tl was increased from 39.6% to 81.0% in the first 2 h treatment. Then the differences in antioxidant capacity of rice exposed to the two Tl species were studied. The contents of malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2˙-) of rice roots exposed to Tl(III) were all higher than those to Tl(I). Meanwhile, the catalase (CAT) activity was significantly depressed and peroxidase (POD) was increased by Tl(III), whereas superoxide dismutase (SOD) showed a rise in both Tl(I) and Tl(III) with no significant difference between them. The expression of metallothionein gene OsMT1a to Tl(I) was upregulated to 255.5 times of Tl(III) though OsMT2c was downregulated to 0.39 times of Tl(III). Overall, the different responses in metallothionein gene expression and antioxidative enzyme activation might result in more ROS accumulation to rice roots by Tl(III) treatment than those by Tl(I).


Assuntos
Metalotioneína/genética , Oryza/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Tálio/toxicidade , Antioxidantes/metabolismo , Catalase/metabolismo , Peróxido de Hidrogênio/metabolismo , Hidroponia , Malondialdeído/metabolismo , Metalotioneína/metabolismo , Oryza/genética , Oryza/metabolismo , Peroxidase/metabolismo , Peroxidases/metabolismo , Raízes de Plantas/metabolismo , Plântula/metabolismo , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo
10.
Chemosphere ; 258: 127353, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554014

RESUMO

Extensive use of antibiotic results in significant antibiotics pollution in the environment. Main objective of this study was to gain insight into potential impacts of antibiotics on plant physiological growth and nutritional composition, and stress alleviation through application of different organic amendments. Effects of five antibiotics (ciprofloxacin, levofloxacin, ofloxacin, amoxicillin and ampicillin) were observed in the presence of three organic amendments (rice husk, farmyard manure and poultry litter) with rice (Oryza sativa L.) as a model plant. Organic amendments were mixed with soil (@ 5 g kg-1) and after three weeks, antibiotics were applied (@10 mg kg-1) and plants were allowed to grow for four months. After which plants were harvested and physical growth parameters (root/shoot length, biomass) and nutritional composition (grain protein content, carbohydrates, phosphorous and iron) were monitored. It was observed that germination rate, seedling root/shoot length, seedling biomass and vigor index were negatively impacted. The application of organic amendments alleviated antibiotic stress on seedling dry biomass, length and vigor index by 1.8-, 3.1- and 2.5-folds, respectively as compared to the antibiotic controls. Concentrations of phosphorous, iron, carbohydrates and proteins were decreased by 5.3-, 1.3-, 1.4- and 1.6-folds upon application of antibiotics. Rice husk was the most effective treatment in case of physical growth parameters and alleviating antibiotics' induced genotoxicity. Whereas, poultry litter had the highest positive effect on nutritional composition of plants. In general, the application of organic amendments alleviated the phytotoxicity as well as genotoxicity in plants under antibiotics stress.


Assuntos
Antibacterianos/toxicidade , Oryza/fisiologia , Poluentes do Solo/toxicidade , Antibacterianos/metabolismo , Biomassa , Poluição Ambiental , Germinação , Esterco , Oryza/metabolismo , Plântula/metabolismo , Solo , Poluentes do Solo/análise
11.
PLoS One ; 15(5): e0233120, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32421736

RESUMO

Day length is a determinant of flowering time in rice. Phytochromes participate in flowering regulation by measuring the number of daylight hours to which the plant is exposed. Here we describe G123, a rice mutant generated by irradiation, which displays insensitivity to the photoperiod and early flowering under both long day and short day conditions. To detect the mutation responsible for the early flowering phenotype exhibited by G123, we generated an F2 population, derived from crossing with the wild-type, and used a pipeline to detect genomic structural variation, initially developed for human genomes. We detected a deletion in the G123 genome that affects the PHOTOPERIOD SENSITIVITY13 (SE13) gene, which encodes a phytochromobilin synthase, an enzyme implicated in phytochrome chromophore biosynthesis. The transcriptomic analysis, performed by RNA-seq, in the G123 plants indicated an alteration in photosynthesis and other processes related to response to light. The expression patterns of the main flowering regulatory genes, such as Ghd7, Ghd8 and PRR37, were altered in the plants grown under both long day and short day conditions. These findings indicate that phytochromes are also involved in the regulation of these genes under short day conditions, and extend the role of phytochromes in flowering regulation in rice.


Assuntos
Flores/metabolismo , Flores/fisiologia , Oryza/genética , Oryza/fisiologia , Fotossíntese/fisiologia , Proteínas de Plantas/metabolismo , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Oryza/metabolismo , Fotossíntese/genética , Proteínas de Plantas/genética
12.
Mol Genet Genomics ; 295(5): 1129-1140, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32458040

RESUMO

Pre-harvest sprouting (PHS) leads to serious economic losses because of reductions in yield and quality. To analyze the quantitative trait loci (QTLs) for PHS resistance in japonica rice, PHS rates on panicles were measured in 160 recombinant inbred lines (RILs) derived from a cross between the temperate japonica varieties Odae (PHS resistant) and Unbong40 (PHS susceptible) under two different environmental conditions-field (summer) and greenhouse (winter) environments. Genome re-sequencing of the parental varieties detected 266,773 DNA polymorphisms including 248,255 single nucleotide polymorphisms and 18,518 insertions/deletions. We constructed a genetic map comprising 239 kompetitive allele-specific PCR and 49 cleaved amplified polymorphic sequence markers. In the field environment, two major QTLs, qPHS-3FD and qPHS-11FD, were identified on chromosomes 3 and 11, respectively, whereas three major QTLs, qPHS-3GH, qPHS-4GH, and qPHS-11GH, were identified on chromosomes 3, 4, and 11, respectively, in the greenhouse environment. qPHS-11GH and qPHS-11FD had similar locations on chromosome 11, suggesting the existence of a gene conferring stable PHS resistance effects under different environmental conditions. The QTLs identified in this study can be used to improve the PHS resistance of japonica varieties, and they may improve our understanding of the genetic basis of PHS resistance.


Assuntos
Oryza/fisiologia , Locos de Características Quantitativas , Sequenciamento Completo do Genoma/métodos , Mapeamento Cromossômico , Germinação , Mutação INDEL , Oryza/genética , Proteínas de Plantas/genética , Polimorfismo de Nucleotídeo Único
13.
J Plant Physiol ; 249: 153165, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32408008

RESUMO

Calmodulin-like proteins (CMLs) have been shown to play key regulatory roles in calcium signaling in plants. However, few bona-fide CMLs binding proteins have been characterized in rice, a monocot model plant. Here, through large-scale screening of a yeast-two hybrid (Y2H) cDNA library with OsCML16 as a bait, six new putative interacting partners of OsCML16 were discovered and confirmed by both pairwise Y2H and bimolecular fluorescence complementation (BiFC) assays. Interestingly, the in vitro peptide-binding assays manifested that OsERD2 could bind both OsCaM1 and OsCML16 whereas other five target proteins could specifically bind OsCML16 but not OsCaM1. Furthermore, Ca2+ and TFP, a calmodulin (CaM) antagonist, were involved in the ABA-induced transcription of OsCML16 and its target genes, and they were also obviously induced by cold, drought, and salt stresses. Taken together, our new findings have provided the basis for the novel signaling pathways of OsCML16 in the abiotic stress response in rice.


Assuntos
Regulação da Expressão Gênica de Plantas , Oryza/fisiologia , Proteínas de Plantas/genética , Temperatura Baixa , Secas , Perfilação da Expressão Gênica , Oryza/genética , Proteínas de Plantas/metabolismo , Estresse Salino/fisiologia , Estresse Fisiológico
14.
Artigo em Inglês | MEDLINE | ID: mdl-32289640

RESUMO

Seed dormancy and germination in rice (Oryza sativa L.) are complex and important agronomic traits that involve a number of physiological processes and energy. A mutant named h470 selected from a60Co-radiated indica cultivar N22 population had weakened dormancy that was insensitive to Gibberellin (GA) and Abscisic acid (ABA). The levels of GA4 and ABA were higher in h470 than in wild-type (WT) plants. The gene controlling seed dormancy in h470 was cloned by mut-map and transgenesis and confirmed to encode an ADP-glucose transporter protein. A 1 bp deletion in Os02g0202400 (OsBT1) caused the weaker seed dormancy in h470. Metabolomics analyses showed that most sugar components were higher in h470 seeds than the wild type. The mutation in h470 affected glycometabolism.


Assuntos
Oryza , Dormência de Plantas , Proteínas de Plantas , Sementes , Ácido Abscísico/farmacologia , Regulação da Expressão Gênica de Plantas , Germinação , Giberelinas/farmacologia , Oryza/fisiologia , Dormência de Plantas/efeitos dos fármacos , Dormência de Plantas/genética , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/genética , Sementes/genética
15.
PLoS One ; 15(3): e0229464, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32176705

RESUMO

Rice production in the Mekong River Delta of Vietnam (MRD) is endangered by sea-level rise and an associated increase in the incidence of salinity intrusion. This paper examines the diffusion of salt tolerant rice varieties in the MRD that were promoted through Consortium for Unfavorable Rice Environments (CURE) activities. Factors associated with adoption of CURE-related varieties are estimated using a random utilty model and a dataset of 800 farm households with rice fields in salinity prone areas of the MRD. Results suggest that there has been widespread adoption of CURE-related varieties in salinity-prone areas. Further, multivariate analysis reveals that environment and location characteristics, rather than household characteristics, are the most important determinants of adoption. In particular, CURE-related varieties are more likely to be adopted in high-salinity-risk areas that are not protected by salinity barrier gates. Neighbhors' adoption decisions also strongly influence household decisions to adopt CURE-related varieties. The contracting of mechanization, particularly for land preparation and harvest, requires the coordination of village households in timing of planting, harvest and varietal duration. This coordination appears to extend to choice of CURE-related varieties. Finally, CURE-related varieties and other varieties generate similar net revenues in a year with low salinity exposure, suggesting that CURE-related varieties are a low-cost insurance policy against salinity inundation in high risk areas. Combined, these results highlight the need to address complex factors beyond current economic profits, like environment, community choices, and risk mitigation, when designing technologies and policies that support farmer adaptation to climatic change.


Assuntos
Adaptação Fisiológica , Mudança Climática , Oryza/crescimento & desenvolvimento , Rios/química , Tolerância ao Sal , Elevação do Nível do Mar , Fazendeiros , Oryza/fisiologia , Vietnã
16.
Chemosphere ; 250: 126337, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32135442

RESUMO

Nitrate reductase is a nitric oxide (NO) induced enzyme in plants, NO acts as a signaling molecule under ZnO NPs-induced stress whereas melatonin (N-acetyl-5-methoxytryptamine) could improve morpho-physiological attributes of plants under adverse conditions. In present study, seedlings of two rice genotypes differed regarding nitrate reductase activities i.e., transgenic 'NR' and wild type 'WT' were applied with two melatonin levels i.e., 0, 10 µΜ regarded as M0, M10, respectively and three levels of ZnO NPs i.e., 0, 50, 500 mg L-1 regarded as ZnO NPs0, ZnO NPs50 and ZnO NPs500, respectively. Results revealed that melatonin application substantially increased the dry biomass accumulation of both rice genotypes under all ZnO NPs levels. The root growth, mineral absorption as well as the antioxidant responses were also improved by melatonin application under ZnO NPs stress. The interactive effects of melatonin and genotype on plant growth, antioxidant responses and mineral contents i.e., Zn, Na, Fe and Mn were also found significant under different ZnO NPs stress. Furthermore, total plant dry weight was significantly correlated with the leaf dry weight, root volume, catalase (CAT) activity in leaves, Na accumulation in stem sheath and Fe accumulation in root under both M0 and M10 treatments. Moreover, the comparative transcriptome analysis identified key genes which were responsible for melatonin and NO-induced modulations in plant growth under ZnO NPs stress. Overall, melatonin could improve the morphological growth of the rice plants by modulating root-shoot characteristics, antioxidant activities and mineral uptake in root and shoot of rice.


Assuntos
Melatonina/metabolismo , Nanopartículas/toxicidade , Nitrato Redutase/metabolismo , Oryza/fisiologia , Óxido de Zinco/toxicidade , Antioxidantes/farmacologia , Biomassa , Genótipo , Oryza/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Plântula/efeitos dos fármacos
17.
Chemosphere ; 251: 126347, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32169700

RESUMO

Currently, exploring effective measures to reduce multiple toxic metals accumulation in rice grains is an urgent issue to be tackled. Pot experiments were thus conducted to explore the effects and mechanisms of foliar spraying with composite sols of silicon (Si) and selenium (Se) during tillering to booting stage on diminishing cadmium (Cd) and lead (Pb) translocation to rice grains and affiliated physiological and biochemical responses in rice seedlings grown in Cd + Pb-polluted soils (positive control). Results showed that Cd and Pb contents in leaves or grains were distinctly below the positive control by the sols. Compared to the positive control, transcriptions of Cd transporter-related genes including OsLCT1, OsCCX2, OsHMA2 and OsPCR1 genes in leaves, and OsLCT1, OsCCX2, TaCNR2 and OSPCR1 in peduncles were downregulated by the increasing sols. Meanwhile, Se-binding protein 1 was evidently upregulated, together to retard Cd and Pb translocation to rice grains. The sols not only upregulated transcriptions of Lhcb1, RbcL, and OsBTF3 genes and production of psbA, Lhcb1 and RbcL proteins, but also increased the chlorophylls contents and RuBP carboxylase activities in the leaves, improving photosynthesis. The sols restrained ROS production from NADPH oxidases, but activated glutathione peroxidase, alleviating oxidative stress and damage. Additionally, Se was significantly enriched and was existed as selenomethionine in the rice grains. However, Pb transporter-related genes remain to be specified. Thus, the composite sols have potential to reduce Cd and Pb accumulation, mitigate oxidative damage, and promote photosynthesis and organic Se enrichment in rice plants under Cd and Pb combined pollution.


Assuntos
Cádmio/toxicidade , Chumbo/toxicidade , Oryza/fisiologia , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Cádmio/análise , Clorofila/metabolismo , Poluição Ambiental , Chumbo/análise , Oryza/química , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese , Folhas de Planta/metabolismo , Plântula/efeitos dos fármacos , Selênio/química , Selênio/metabolismo , Silício/química , Silício/metabolismo , Solo/química , Poluentes do Solo/análise
18.
Artigo em Inglês | MEDLINE | ID: mdl-32114250

RESUMO

Potassium homeostasis is essential for pollen development and pollen-pistil interactions during the sexual reproduction of flowering plants. Here, we described the role of a Shaker K+ channel, OsAKT1.2, in rice pollen germination and growth. OsAKT1.2 is specifically expressed in the tricellular pollen, mature pollen grains and growing pollen tubes. Using CRISPR gene editing, we found that knockout lines did not differ from wildtype in vegetative growth, but showed decreased pollen germination rate both in the germination medium and in vivo. OsAKT1.2-GFP fusion protein was localized in the plasma membrane and enriched at the pollen tube tip. OsAKT1.2 could complement the yeast strain which is deficient in K+ intake. These findings suggest that OsAKT1.2 is associated with pollen germination and tube elongation in rice.


Assuntos
Germinação/genética , Oryza/fisiologia , Proteínas de Plantas/genética , Pólen/crescimento & desenvolvimento , Canais de Potássio/genética , Sequência de Bases , Oryza/genética , Proteínas de Plantas/metabolismo
19.
Artigo em Inglês | MEDLINE | ID: mdl-32213379

RESUMO

Cold stress is one of the most common unfavorable environmental factors affecting the growth, development, and survival of plants. The DEAD-box RNA helicases play important roles in all types of processes of RNA metabolism. However, the function of DEAD-box RNA helicase under cold stress is poorly explored in plants, especially in rice. This study reported the identification of a novel rice thermo-sensitive chlorophyll-deficient mutant, tcd33, which displayed an albino phenotype before the four-leaf stage, then withered and eventually died at 20 °C, while wild-type plants exhibited normal green coloration at 32 °C. The tcd33 seedlings also exhibited less chlorophyll contents and severe defects of chloroplast structure under 20 °C condition. Map-based cloning and complementation experiments suggested that TCD33 encodes a chloroplast-located DEAD-box RNA helicase protein. The transcript expression level of TCD33 indicated that the genes related to chlorophyll (Chl) biosynthesis, photosynthesis, and chloroplast development in tcd33 mutants were down-regulated at 20 °C, while the down-regulated genes were nearly recovered to or slightly higher than the WT level at 32 °C. Together, our results suggest that the cold-inducible TCD33 is essential for early chloroplast development and is important for cold-responsive gene regulation and cold tolerance in rice.


Assuntos
Cloroplastos/metabolismo , Resposta ao Choque Frio/genética , RNA Helicases DEAD-box/genética , Oryza/fisiologia , Proteínas de Plantas/genética , Sequência de Aminoácidos , RNA Helicases DEAD-box/química , RNA Helicases DEAD-box/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Filogenia , Proteínas de Plantas/metabolismo , Plântula/metabolismo , Alinhamento de Sequência
20.
Artigo em Inglês | MEDLINE | ID: mdl-32220787

RESUMO

Paspalum urvillei and Setaria parviflora are two plant species naturally adapted to iron-rich environments such as around iron mines wastes. The aim of our work was to characterize how these two species cope with these extreme conditions by comparing them with related model species, Oryza sativa and Setaria viridis, that appeared to be much less tolerant to Fe excess. Both Paspalum urvillei and Setaria parviflora were able to limit the amount of Fe accumulated within roots and shoots, compared to the less tolerant species. Perls/DAB staining of Fe in root cross sections indicated that Paspalum urvillei and Setaria parviflora responded through the build-up of the iron plaque (IP), suggesting a role of this structure in the limitation of Fe uptake. Synchrotron µXRF analyses showed the presence of phosphorus, calcium, silicon and sulfur on IP of Paspalum urvillei roots and µXANES analyses identified Fe oxyhydroxide (ferrihydrite) as the main Fe form. Once within roots, high concentrations of Fe were localized in the cell walls and vacuoles of Paspalum urvillei, Setaria parviflora and O. sativa whereas Setaria viridis accumulated Fe in ferritins. The Fe forms translocated to the shoots of Setaria parviflora were identified as tri-iron complexes with citrate and malate. In leaves, all species accumulated Fe in the vacuoles of bundle sheath cells and as ferritin complexes in plastids. Taken together, our results strongly suggest that Paspalum urvillei and Setaria parviflora set up mechanisms of Fe exclusion in roots and shoots to limit the toxicity induced by Fe excess.


Assuntos
Ferro/metabolismo , Paspalum/fisiologia , Setaria (Planta)/fisiologia , Oryza/fisiologia , Raízes de Plantas/metabolismo , Solo/química
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