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1.
Biol Res ; 52(1): 43, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31405373

RESUMO

BACKGROUND: Drought is one of the main serious problems for agriculture production which its intensity is increasing in many parts of the world, hence, improving water use efficiency is a main goal for sustainable agriculture. RESULTS: Growth indices including relative shoot length growth (SL), relative stem diameter increase (SD) and relative trunk cross sectional area growth (TCSA) measured at the start and end of the season decreased by reducing the irrigation level. Chlorophyll index (CI) was decreased at 70% crop evapotranspiration, however water use efficiency (WUE), leaf and fruit total phenolic content (TPC), and fruit anthocyanin content (AC) were among the traits that showed increment by water deficit stress in both cultivars. Shafi-Abadi cultivar showed to be more sensitive to the water stress than 'Golab'. Kaolin treatment improved SL, SD and CI traits, but this increase was statistically significant only for SD at 5% level. Kaolin had no significant effect on yield and water use efficiency (WUE), however, it had negative effect on yield efficiency (YE). Kaolin treatments also significantly increased fruit and leaf TPC (P < 0.01) but had no effect on leaf and fruit total antioxidant activity (AA), as well as fruit anthocyanin content (AC) and soluble proteins (SP). CONCLUSIONS: Irrigation at 85% ETc showed better results than 100% and 70% ETc levels for yield attributes. It seems that the more pronounced effect of kaolin on vegetative traits but not on the fruits, might be attributed to the early ripening and harvest time of the examined cultivars.


Assuntos
Irrigação Agrícola/métodos , Secas , Frutas/crescimento & desenvolvimento , Caulim/administração & dosagem , Malus/crescimento & desenvolvimento , Frutas/efeitos dos fármacos , Malus/efeitos dos fármacos , Estações do Ano
3.
Plant Sci ; 286: 108-117, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300136

RESUMO

It has been reported that drought stress (DS) reduces cotton yield by negatively affecting reproductive activities. Some studies have investigated the effects of DS on pollen physiology and biochemistry, but studies exploring the impact of drought on pistil biochemistry and its relationship with pollen tube growth rates in vivo are scarce. In order to investigate these objectives, a greenhouse study was conducted with a drought sensitive cotton cultivar, Yuzaomian 9110. Two water treatments were imposed at flowering stage, 1. control, where plants were irrigated with optimum quantity of water and 2. DS treatment, where plants were irrigated with 50% of the optimum quantity of water. Results indicated that stored starch content at the early stage of pollen tube growth (12:00 h) was 31.6% lower in drought-stressed pistils than control pistils, and it was highly correlated with pollen tube growth rate. The decline in starch accumulation of drought-stressed pistils could be attributed to the impeded transport of photosynthetic carbon assimilates. Moreover, decreased ADP-glucose pyrophosphorylase and soluble starch synthase activities also resulted in curtailing starch accumulation in drought-stressed pistils. Furthermore, pistil sucrose concentration was significantly higher in droughted plants relative to control plants at 12:00 and 18:00 h (during the rapid growth period), which was due to lower activities of sucrose synthase and acid invertase, and the down-regulated expressions of sucrose synthase genes, GhSusA, GhSusB and GhSusD, and acid invertase genes, GhINV1 and GhINV2, in drought-stressed pistils, limiting as a result the hydrolysis of sucrose into hexose. Drought-stressed pistils sampled at 18:00 h had lower α-amylase activity compared to control pistils, resulting in decreased starch decomposition, which, in conjunction with the decreased hydrolysis of sucrose, led to lower glucose and fructose contents in drought-stressed pistils at 18:00 h. Finally, lower pyruvate level in drought-stressed pistils could not produce enough acetyl-CoA in the tricarboxylic acid cycle to yield sufficient energy (ATP) for pollen tube growth. We conclude that DS disrupts the carbohydrate balance of pistil, reducing as a consequence carbon and energy supply for pollen tube elongation in the style, which will ultimately result in reproductive failure.


Assuntos
Metabolismo dos Carboidratos , Secas , Gossypium/genética , Gossypium/metabolismo , Flores/metabolismo , Tubo Polínico/crescimento & desenvolvimento , Tubo Polínico/metabolismo
4.
Sheng Wu Gong Cheng Xue Bao ; 35(7): 1277-1285, 2019 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-31328484

RESUMO

Leaf water potential of peanut subjected to drought stress is positively related to the oil content of peanut kernels. The aim of this study was to directly screen the high oil mutants of peanut and create the new peanut varieties using hydroxyproline as water potential regulator. In vitro mutagenesis was carried out with the embryonic leaflets of peanut variety Huayu 20 as explants and pingyangmycin as a mutagen added into the somatic embryo formation medium. The formed somatic embryos were successively transferred to somatic embryo germination and selection medium containing 6 mmol/L hydroxyproline (at -2.079 MPa water potential ) to induce regeneration and directionally screen high oil content mutants. After that, these plantlets were grafted and transplanted to the experimental field and 132 high oil mutants with oil content over 55% were obtained from the offspring of regenerated plants. Finally, among them, the oil contents of 27 lines were higher than 58% and of 2 lines were higher than 60%. A new peanut variety Yuhua 9 with high yield and oil content was bred from the regenerated plant progenies combining the pedigree breeding method. The yield was 14.0% higher than that of the control cultivar in the testing new peanut varieties of Liaoning province, and also it has passed the national registration of non-major crop varieties. Yuhua 9 with an oil content of 61.05%, which was 11.55 percentage points higher than that of the parent Huayu 20, was the peanut cultivar with the highest oil content in the world. The result showed that it was an effective way for directional breeding of high oil peanut varieties by means of the three-step technique including in vitro mutagenesis, directional screening by reducing water potential in medium and pedigree selection of regenerated plant progenies.


Assuntos
Arachis , Germinação , Secas , Mutagênese , Melhoramento Vegetal
5.
DNA Cell Biol ; 38(8): 824-839, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31295023

RESUMO

Tea plant is an important economic crop on a global scale. Its yield and quality are affected by abiotic stress. The calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) family genes play irreplaceable roles in plant development and stress resistance. More and more CBL-CIPK genes have been identified, but a few CBL-CIPK genes have been cloned and characterized in tea plants. In this study, 7 CsCBLs and 18 CsCIPKs were identified based on the tea plant genome. Physicochemical properties, phylogenetic, conserved motifs, gene structure, homologous gene network, and promoter upstream elements of these 25 genes were analyzed. Conserved motifs of these genes varied with phylogenetic tree node. From the genetic structure, members of the tea plant CIPK gene family can be divided into two types: intron rich and no intron. Many stress-related elements were found in the 2000 bp upstream of the promoter, and PlantCARE predicted that CsCBL4 contained 30 stress-related elements. PlantPAN2 shows that CsCIPK6 contains 48 ABRELATERD1; CsCIPK17 contains 37 GT1CONSENSUS; CsCIPK3 contains 64 MYBCOREATCYCB1; CsCBL3 contains 52 SORLIP1AT; CsCBL5 contains 65 SURECOREATSULTR11; and CsCIPK11 contains 83 WBOXATNPR1. In addition, eight genes were selected for quantitative real-time PCR (RT-qPCR) to detect their expression profiles under high-temperature, low-temperature, salt, and drought treatments. These genes were found to be responsive to one or more abiotic stress treatments. The expression levels of CsCBL4, CsCIPK2, and CsCIPK14 were similar, and they were homologous to AtSOS3 and AtSIP3 and AtSIP4 in Arabidopsis, which were involved in the SOS pathway. This study provides insight into the potential functions of the CsCBL and CsCIPK of tea plant.


Assuntos
Camellia sinensis/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas Serina-Treonina Quinases/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Ligação ao Cálcio/genética , Camellia sinensis/fisiologia , Sequência Conservada , Secas , Evolução Molecular , Redes Reguladoras de Genes , Estudo de Associação Genômica Ampla , Anotação de Sequência Molecular , Filogenia , Proteínas de Plantas/metabolismo , Estresse Fisiológico/genética
6.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2021-2029, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257775

RESUMO

Fraction of absorbed photosynthetically active radiation (fAPAR) is one of the important remote sensing model parameters of vegetation productivity. However, the crop canopy fAPAR estimation during growing season under different drought conditions has not been reported yet. In this study, the characteristics of summer maize canopy fAPAR and spectral reflectance during growing season under different drought stresses and the relationships of fAPAR with reflectance, the first derivative spectral reflectance and vegetation indices were examined based on the hyperspectral reflectance and fAPAR data from the summer maize drought manipulation experiment with five irrigation levels in 2015. Under mild water stress and sufficient water supply conditions, fAPAR was higher, with the maximum value of 0.7. Under severe water stress and severe persistent drought, fAPAR was lower, with the minimum value of 0.06. Reflectance of visible and shortwave bands increased and near infrared reflectance decreased with increasing drought. The fAPAR was negatively related with visible bands and shortwave bands, but positively correlated with near infrared. Visible and shortwave band reflectance had significant correlation with fAPAR, especially at 383, 680 and 1980 nm, with all the correlation coefficients being more than -0.87. The strong and stable relationship between the first derivative spectral reflectance and fAPAR appeared at 580, 720 and 1546 nm, with the correlation coefficients being -0.91, 0.89 and 0.88, respectively. There were linear or logarithm relationships between fAPAR with nine vegetation indices. Among the nine indices, the enhanced vegetation index (EVI), renormalized difference vegetation index (RDVI), soil adjusted vegetation index (SAVI), and modified soil adjusted vegetation index (MSAVI) performed well with the correlation coefficient being higher than 0.88, and the average relative error (RMAE) 16.6%, 16.6%, 16.7% and 16.2%, respectively. Based on the logarithmic relationship between first derivative spectral reflectance and fAPAR, the simulation effect was best at the band of (720±5) nm, with a correlation coefficient of 0.86. The correlation coefficient of the relationship between fAPAR and reflectance was less than 0.81. The results could provide fAPAR simulation for remote sensing model of vegetation productivity and drought warning.


Assuntos
Secas , Zea mays , Fotossíntese , Folhas de Planta , Tecnologia de Sensoriamento Remoto , Estações do Ano , Solo
7.
Physiol Plant ; 166(4): 892-893, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31294874

RESUMO

Drought is an increasingly common climatic event that can devastate ecosystems, as well as surrounding agricultural and forestry industries. Few places face this challenge more than Australia, where millennia of droughts linked to geography and climatic drivers, such as El Niño, have shaped the flora and fauna into forms predicated on resilience and economy. How an organism responds to these cyclic challenges is a combination of the inherent tolerance mechanisms encoded in their genome and outside influences, such as the effect of nutrients and symbiotic interactions. In this issue of Physiologia Plantarum, Tariq et al. (2019) describes how the presence of the element phosphorus can bolster the physiological and biochemical response of eucalypt seedlings to severe drought conditions.


Assuntos
Secas , Genoma de Planta/genética , Fósforo/metabolismo , Plântula/genética , Plântula/metabolismo , Austrália
8.
Yi Chuan ; 41(6): 534-547, 2019 Jun 20.
Artigo em Chinês | MEDLINE | ID: mdl-31257201

RESUMO

Oxidative stress caused by reactive oxygen species (ROS) is one of the major abiotic stresses in plants. Under adverse growth conditions, the incoordination of various metabolic processes in plant cells can result in increased hydrogen peroxide (H2O2), thus causing a variety of threats and injuries to plant cells. Ascorbate peroxidase (APX) is an important enzyme to remove H2O2 in plants. In Arabidopsis thaliana, there are eight APX gene family members, including APX1?APX6, sAPX and tAPX. In this study, we analyzed the expression patterns of the eight APX genes in the wild-type and apx mutant plants at different developmental stages and under different abiotic stress conditions. Meanwhile, the tolerance of each apx mutant to salt, drought and heat stresses was studied. qRT-PCR analysis showed that during development (from 4 to 8 weeks old), APX1 and APX2 exhibited the highest and lowest expression levels, respectively. In addition, the expression levels of APX4, sAPX and tAPX decreased during development, while the expression of APX6 increased with the maturity of the plants. Moreover, under different abiotic stress conditions, APX1, APX2 and APX6 were significantly induced by heat stress, sAPX actively responded to salt stress, and APX3 and APX5 exhibited obvious responses to salt, drought and heat stresses. Further tolerance analysis showed that the resistance of all apx mutants to salt and drought stresses was lower than that of the wild-type plant at both germination and maturity stages. At germination stage, all apx mutants were more sensitive to drought stress than to salt stress. At maturity stage, the apx1 and apx6 mutants were more sensitive to salt and drought stresses than the wild-type and other apx mutant plants. The physiological indexes indicated that the H2O2 content in all mutants, especially in the apx1, sapx and tapx, was significantly higher than that in the wild type 10 days after drought stress treatment, the malondialdehyde (MDA) content in all mutants was significantly higher than that in the wild type 5 days after salt stress treatment, while heat stress treatment for 2 h resulted in a significant increase in the contents of H2O2 and MDA in apx1, apx2 and apx6, especially in apx2. Taken together, our study revealed that all eight APX members of Arabidopsis participate in the growth and developmental processes and the abiotic stress responses, with some specific APXs playing a major role in a certain process.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/crescimento & desenvolvimento , Ascorbato Peroxidases/fisiologia , Família Multigênica , Estresse Fisiológico , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Ascorbato Peroxidases/genética , Secas , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio , Plantas Geneticamente Modificadas
9.
Plant Mol Biol ; 101(1-2): 203-220, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31297725

RESUMO

KEY MESSAGE: Here, a functional characterization of a wheat MSR has been presented: this protein makes a contribution to the plant's tolerance of abiotic stress, acting through its catalytic capacity and its modulation of ROS and ABA pathways. The molecular mechanism and function of certain members of the methionine sulfoxide reductase (MSR) gene family have been defined, however, these analyses have not included the wheat equivalents. The wheat MSR gene TaMSRA4.1 is inducible by salinity and drought stress and in this study, we demonstrate that its activity is restricted to the Met-S-SO enantiomer, and its subcellular localization is in the chloroplast. Furthermore, constitutive expression of TaMSRA4.1 enhanced the salinity and drought tolerance of wheat and Arabidopsis thaliana. In these plants constitutively expressing TaMSRA4.1, the accumulation of reactive oxygen species (ROS) was found to be influenced through the modulation of genes encoding proteins involved in ROS signaling, generation and scavenging, while the level of endogenous abscisic acid (ABA), and the sensitivity of stomatal guard cells to exogenous ABA, was increased. A yeast two-hybrid screen, bimolecular fluorescence complementation and co-immunoprecipitation assays demonstrated that heme oxygenase 1 (HO1) interacted with TaMSRA4.1, and that this interaction depended on a TaHO1 C-terminal domain. In plants subjected to salinity or drought stress, TaMSRA4.1 reversed the oxidation of TaHO1, activating ROS and ABA signaling pathways, but not in the absence of HO1. The aforementioned properties advocate TaMSRA4.1 as a candidate for plant genetic enhancement.


Assuntos
Heme Oxigenase-1/metabolismo , Metionina Sulfóxido Redutases/metabolismo , Transdução de Sinais , Estresse Fisiológico , Triticum/enzimologia , Ácido Abscísico/metabolismo , Arabidopsis/enzimologia , Arabidopsis/genética , Arabidopsis/fisiologia , Secas , Perfilação da Expressão Gênica , Heme Oxigenase-1/genética , Metionina Sulfóxido Redutases/genética , Oxirredução , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Tolerância ao Sal , Plântula/enzimologia , Plântula/genética , Plântula/fisiologia , Triticum/genética , Triticum/fisiologia , Técnicas do Sistema de Duplo-Híbrido
10.
BMC Plant Biol ; 19(1): 231, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31159735

RESUMO

BACKGROUND: Four-Coumarate:CoA ligase gene (4CL) plays multiple important roles in plant growth and development by catalyzing the formation of CoA ester. 4CL belongs to the plant phenylpropane derivative, which is related to the synthesis of flavonoids and lignin and is a key enzyme in the biosynthetic pathway. RESULTS: In this study, 12 4CL genes of Fraxinus mandschurica were identified and named Fm4CL1-Fm4CL12, respectively. The analysis of the expression pattern of Fm4CL genes indicate that Fm4CL-like 1 gene may play a role in the lignin synthesis pathway. Our study indicate that overexpression of Fm4CL-like 1 increases the lignin content of transgenic tobacco by 39.5% compared to WT, and the S/G ratio of transgenic tobacco increased by 19.7% compared with WT. The xylem cell layer of transgenic line is increased by 40% compared to WT, the xylem cell wall thickness increased by 21.6% compared to the WT. Under mannitol-simulated drought stress, the root length of transgenic tobacco is 64% longer than WT, and the seed germination rate of the transgenic lines is 47% higher than that of WT. In addition, the H2O2 content in the transgenic tobacco was 22% lower than that of WT, while the POD and SOD content was higher than WT by 30 and 24% respectively, which showed Fm4CL-like 1 affect the accumulation of reactive oxygen species (ROS). The MDA content and relative conductivity was 25 and 15% lower than WT, respectively. The water loss rate is 16.7% lower than that of WT. The relative expression levels of stress-related genes NtHAK, NtAPX, NtCAT, NtABF2, and NtZFP were higher than those of WT under stress treatment. The stomatal apertures of OE (Overexpression) were 30% smaller than those of WT, and the photosynthetic rate of OE was 48% higher than that of WT. These results showed that the overexpression line exhibited stronger adaptability to osmotic stress than WT. CONCLUSIONS: Our results indicate that Fm4CL-like 1 is involved in secondary cell wall development and lignin synthesis. Fm4CL-like 1 play an important role in osmotic stress by affecting cell wall and stomatal development.


Assuntos
Secas , Proteínas de Plantas/genética , Tabaco/fisiologia , Clonagem Molecular , Fraxinus/genética , Fraxinus/metabolismo , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico/genética , Tabaco/genética
11.
BMC Plant Biol ; 19(1): 242, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31174465

RESUMO

BACKGROUND: Recurrent drought associated with climate change is a major constraint to wheat (Triticum aestivum L.) productivity. This study aimed to (i) quantify the effects of addition/substitution/translocation of chromosome segments from wild relatives of wheat on the root, physiological and yield traits of hexaploid wheat under drought, and (ii) understand the mechanism(s) associated with drought tolerance or susceptibility in wheat-alien chromosome lines. METHODS: A set of 48 wheat-alien chromosome lines (addition/substitution/translocation lines) with Chinese Spring background were used. Seedling root traits were studied on solid agar medium. To understand the influence of drought on the root system of adult plants, these 48 lines were grown in 150-cm columns for 65 d under full irrigation or withholding water for 58 d. To quantify the effect of drought on physiological and yield traits, the 48 lines were grown in pots under full irrigation until anthesis; after that, half of the plants were drought stressed by withholding water for 16 d before recording physiological and yield-associated traits. RESULTS: The alien chromosome lines exhibited altered root architecture and decreased photochemical efficiency and seed yield and its components under drought. The wheat-alien chromosome lines T5DS·5S#3L (TA5088) with a chromosome segment from Aegilops speltoides (5S) and T5DL.5 V#3S (TA5638) with a chromosome segment from Dasypyrum villosum (5 V) were identified as drought tolerant, and the drought tolerance mechanism was associated with a deep, thin and profuse root system. CONCLUSIONS: The two germplasm lines (TA5088 and TA5638) could be used in wheat breeding programs to improve drought tolerance in wheat and understand the underlying molecular genetic mechanisms of root architecture and drought tolerance.


Assuntos
Cromossomos de Plantas/genética , Secas , Genes de Plantas/genética , Melhoramento Vegetal , Triticum/genética , Aegilops/genética , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Poaceae/genética , Triticum/anatomia & histologia , Triticum/crescimento & desenvolvimento
12.
World J Microbiol Biotechnol ; 35(6): 90, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31147784

RESUMO

The ability of plant growth promoting rhizobacteria (PGPR) for imparting abiotic stress tolerance to plants has been widely explored in recent years; however, the diversity and potential of these microbes have not been maximally exploited. In this study, we characterized four bacterial strains, namely, Pseudomonas aeruginosa PM389, Pseudomonas aeruginosa ZNP1, Bacillus endophyticus J13 and Bacillus tequilensis J12, for potential plant growth promoting (PGP) traits under osmotic-stress, induced by 25% polyethylene glycol (PEG) in the growth medium. Growth curve analysis was performed in LB medium with or without PEG, in order to understand the growth patterns of these bacteria under osmotic-stress. All strains were able to grow and proliferate under osmotic-stress, although their growth rate was slower than that under non-stressed conditions (LB without PEG). Bacterial secretions were analyzed for the presence of exopolysaccharides and phytohormones and it was observed that all four strains released these compounds into the media, both, under stressed and non-stressed conditions. In the Pseudomonas strains, osmotic stress caused a decrease in the levels of auxin (IAA) and cytokinin (tZ), but an increase in the levels of gibberellic acid. The Bacillus strains on the other hand showed a stress-induced increase in the levels of all three phytohormones. P. aeruginosa ZNP1 and B. endophyticus J13 exhibited increased EPS production under osmotic-stress. While osmotic stress caused a decrease in the levels of EPS in P. aeruginosa PM389, B. tequilensis J12 showed no change in EPS quantities released into the media under osmotic stress when compared to non-stressed conditions. Upon inoculating Arabidopsis thaliana seedlings with these strains individually, it was observed that all four strains were able to ameliorate the adverse effects of osmotic-stress (induced by 25% PEG in MS-Agar medium) in the plants, as evidenced by their enhanced fresh weight, dry weight and plant water content, as opposed to osmotic-stressed, non-inoculated plants.


Assuntos
Arabidopsis/microbiologia , Fenômenos Fisiológicos Bacterianos , Secas , Pressão Osmótica , Desenvolvimento Vegetal , Reguladores de Crescimento de Planta/metabolismo , Polissacarídeos Bacterianos/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Bacillus/crescimento & desenvolvimento , Bacillus/fisiologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Citocininas/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Rizosfera , Plântula/crescimento & desenvolvimento , Microbiologia do Solo , Estresse Fisiológico/fisiologia
13.
Gene ; 710: 279-290, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31200083

RESUMO

Plants are frequently exposed to variable environmental stresses that adversely affect plant growth, development and agricultural production. In this study, a trypanothione synthetase gene from Trypanosoma cruzi, TcTryS, was chemically synthesized and its roles in tolerance to multiple abiotic stresses were functionally characterized by generating transgenic rice overexpressing TcTryS. Overexpression of TcTryS in rice endows transgenic plants with hypersensitivity to ABA, hyposensitivity to NaCl- and mannitol-induced osmotic stress at the seed germination stage. TcTryS overexpression results in enhanced tolerance to drought, salt, cadmium, and 2,4,6-trichlorophenol stresses in transgenic rice, simultaneously supported by improved physiological traits. The TcTryS-overexpression plants also accumulated greater amounts of proline, less malondialdehyde and more transcripts of stress-related genes than wild-type plants under drought and salt stress conditions. In addition, TcTryS might play a positive role in maintaining chlorophyll content under 2,4,6-trichlorophenol stress. Histochemical staining assay showed that TcTryS renders transgenic plants better ROS-scavenging capability. All of these results suggest that TcTryS could function as a key regulator in modulation of abiotic stress tolerance in plant, and may have applications in the engineering of economically important crops.


Assuntos
Amida Sintases/genética , Amida Sintases/metabolismo , Oryza/genética , Estresse Fisiológico , Trypanosoma cruzi/enzimologia , Ácido Abscísico/farmacologia , Cádmio/toxicidade , Secas , Regulação da Expressão Gênica de Plantas , Oryza/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Tolerância ao Sal , Trypanosoma cruzi/genética , Regulação para Cima
14.
Gene ; 710: 375-386, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31200084

RESUMO

Cynanchum thesioides are upright, xerophytic shrubs that are widely distributed in arid and semi-arid areas of China, North Korea, Mongolia and Siberia. To date, little is known about the molecular mechanisms of drought resistance in C. thesioides. To better understand drought resistance, we used transcriptome analysis and Illumina sequencing technology on C. thesioides, to identify drought-responsive genes. Using de novo assembly 55,268 unigenes were identified from 207.58 Gb of clean data. Amongst these, 36,265 were annotated with gene descriptions, conserved domains, gene ontology terms and metabolic pathways. The sequencing results showed that genes that were differentially expressed (DEGs) under drought stress were enriched in pathways such as carbon metabolism, starch and sucrose metabolism, amino acid biosynthesis, phenylpropanoid biosynthesis and plant hormone signal transduction. Moreover, many functional genes were up-regulated under severe drought stress to enhance tolerance. Weighted gene co-expression network analysis showed that there were key hub genes related to drought stress. Hundreds of candidate genes were identified under severe drought stress, including transcriptional factors such as MYB, G2-like, ERF, C2H2, NAC, NF-X1, GRF, HD-ZIP, HB-other, HSF, C3H, GRAS, WRKY, bHLH and Trihelix. These data are a valuable resource for further investigation into the molecular mechanism for drought stress in C. thesioides and will facilitate exploration of drought resistance genes.


Assuntos
Cynanchum/genética , Secas , Perfilação da Expressão Gênica/métodos , Redes Reguladoras de Genes , Regulação da Expressão Gênica de Plantas , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Anotação de Sequência Molecular , Proteínas de Plantas/genética , Análise de Sequência de RNA/métodos , Estresse Fisiológico
15.
BMC Plant Biol ; 19(1): 267, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31221078

RESUMO

BACKGROUND: Sesame is an important oil crop due to its high oil, antioxidant, and protein content. Drought stress is a major abiotic stress that affects sesame production as well as the quality of sesame seed. To reveal the adaptive mechanism of sesame in response to water deficient conditions, transcriptomic and metabolomics were applied in drought-tolerant (DT) and drought-susceptible (DS) sesame genotypes. RESULTS: Transcriptomic analysis reveals a set of core drought-responsive genes (684 up-regulated and 1346 down-regulated) in sesame that was robustly differently expressed in both genotypes. Most enriched drought-responsive genes are mainly involved in protein processing in endoplasmic reticulum, plant hormone signal transduction photosynthesis, lipid metabolism, and amino acid metabolism. Drought-susceptible genotype was more disturbed by drought stress at both transcriptional and metabolic levels, since more drought-responsive genes/metabolites were identified in DS. Drought-responsive genes associated with stress response, amino acid metabolism, and reactive oxygen species scavenging were more enriched or activated in DT. According to the partial least-squares discriminate analysis, the most important metabolites which were accumulated under drought stress in both genotypes includes ABA, amino acids, and organic acids. Especially, higher levels of ABA, proline, arginine, lysine, aromatic and branched chain amino acids, GABA, saccharopine, 2-aminoadipate, and allantoin were found in DT under stress condition. Combination of transcriptomic and metabolomic analysis highlights the important role of amino acid metabolism (especially saccharopine pathway) and ABA metabolism and signaling pathway for drought tolerance in sesame. CONCLUSION: The results of the present study provide valuable information for better understanding the molecular mechanism underlying drought tolerance of sesame, and also provide useful clues for the genetic improvement of drought tolerance in sesame.


Assuntos
Secas , Sesamum/genética , Adaptação Fisiológica/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genótipo , Metabolômica , Sesamum/fisiologia
16.
Plant Physiol Biochem ; 141: 215-224, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31181509

RESUMO

Plants are usually exposed to several types of abiotic stress in regular field conditions. The lipid profile of barley homozygous lines exposed to drought, heat, salinity, and their combinations, was investigated in the present study. Free fatty acids, free sterols, and diacylglycerols were the most abundant classes (∼8.0% of plant material). The genetic background significantly impacted the lipid composition rather than the treatments, and diacylglycerols were the only lipid class affected by salinity (1.84 mg/100 mg plant tissue; ∼33% reduction). However, the genotype × treatment interaction analysis revealed that the lipid and sterol compositions depended on both genotype and environment. Our results suggest that inborn stress tolerance in barley is manifested by enhanced accumulation of most lipids, mainly sterols, especially in heat/drought-stressed plants. In addition, expression of the LTP2 gene may be indirectly involved in the abiotic stress reaction of barley by mediating intracellular transport of some lipid classes.


Assuntos
Hordeum/química , Lipídeos/química , Folhas de Planta/química , Esteróis/química , Estresse Fisiológico , Adaptação Fisiológica , Diglicerídeos/química , Secas , Ácidos Graxos não Esterificados/química , Cromatografia Gasosa-Espectrometria de Massas , Perfilação da Expressão Gênica , Genótipo , Hordeum/genética , Temperatura Alta , Fenótipo , Fitosteróis/química , Folhas de Planta/genética , Reprodutibilidade dos Testes , Salinidade
17.
Plant Physiol Biochem ; 141: 300-305, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31202194

RESUMO

MYB-type transcription factors are known to participate in the response of plants to a number of stress agents. MsMYB2L is an alfalfa member of this large gene family. Its transcription in alfalfa seedlings was found to be rapidly and strongly induced by salinity, moisture deficiency and exogenously supplied abscisic acid. An analysis based on a yeast one hybrid assay indicated that its product is able to activate transcription, consistent with its function as a transcription factor. When the gene was constitutively expressed in Arabidopsis thaliana, both germination and seedling growth were more sensitive to ABA treatment than wild type, and growth was less strongly compromised by salinity and moisture deficiency stress, presumably as a result of the induction of certain stress-related genes active in ABA-dependent pathways. The transgenic seedlings' enhanced the synthesis of many osmotic regulatory substances such as proline and soluble sugar, and decreased the lipid peroxidation. In all, MsMYB2L represents a potential candidate gene for manipulating the salinity and drought tolerance of alfalfa.


Assuntos
Ácido Abscísico/metabolismo , Arabidopsis/fisiologia , Proteínas de Ligação a DNA/genética , Secas , Medicago sativa/genética , Proteínas de Plantas/genética , Salinidade , Fatores de Transcrição/genética , Regulação da Expressão Gênica de Plantas , Técnicas Genéticas , Germinação , Filogenia , Plantas Geneticamente Modificadas/fisiologia , Polietilenoglicóis/química , Plântula/fisiologia , Estresse Fisiológico , Açúcares/química , Transcrição Genética , Ativação Transcricional
18.
Plant Physiol Biochem ; 141: 315-324, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207492

RESUMO

Different SA concentrations (10, 100 and 1000 µM) were applied in young olive trees (Olea europaea L.) subjected to drought and rewatering. Plants treated with 10 µM exhibited a close behavior to SA-starved plants. Although both 100 and 1000 µM improved the balance between ROS production and scavenging, 100 µM was more efficient. During drought, 100 µM improved ROS detoxification and scavenging by the maintenance or overaccumulation of soluble proteins. During recovery, soluble proteins return to well-watered values and increased the investment in non-enzymatic antioxidants. 100 µM was also the most effective in plant ionome regulation, improving macro and micronutrients uptake, namely P, Fe, Mn and Zn, and changing mineral allocation patterns. Therefore, 100 µM also countered the drought-induced decline in total plant biomass accumulation. The application of suitable SA concentrations is an efficient tool to improve cellular homeostasis and growth of plants subjected to recurrent drought episodes.


Assuntos
Secas , Íons/metabolismo , Olea/metabolismo , Oxirredução , Folhas de Planta/metabolismo , Ácido Salicílico/farmacologia , Antioxidantes/química , Biomassa , Minerais/química , Nutrientes/química , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/metabolismo , Portugal , Espécies Reativas de Oxigênio/metabolismo , Água/metabolismo
19.
Plant Physiol Biochem ; 141: 343-352, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207495

RESUMO

Plant U-box (PUB) E3 ubiquitin ligases play crucial roles in the plant response to abiotic stress and the phytohormone abscisic acid (ABA) signaling, but little is known about them in bryophytes. Here, a representative U-box armadillo repeat (PUB-ARM) ubiquitin E3 ligase from Antarctic moss Pohlia nutans (PnSAG1), was explored for its role in abiotic stress response in Arabidopsis thaliana and Physcomitrella patens. The expression of PnSAG1 was rapidly induced by exogenous abscisic acid (ABA), salt, cold and drought stresses. PnSAG1 was localized to the cytoplasm and showed E3 ubiquitin ligase activity by in vitro ubiquitination assay. The PnSAG1-overexpressing Arabidopsis enhanced the sensitivity with respect to ABA and salt stress during seed germination and early root growth. Similarly, heterogeneous overexpression of PnSAG1 in P. patens was more sensitive to the salinity and ABA in their gametophyte growth. The analysis by RT-qPCR revealed that the expression of salt stress/ABA-related genes were downregulated in PnSAG1-overexpressing plants after salt treatment. Taken together, our results indicated that PnSAG1 plays a negative role in plant response to ABA and salt stress.


Assuntos
Ácido Abscísico/farmacologia , Arabidopsis/fisiologia , Briófitas/enzimologia , Bryopsida/fisiologia , Estresse Salino , Ubiquitina-Proteína Ligases/genética , Regiões Antárticas , Arabidopsis/genética , Briófitas/genética , Bryopsida/genética , Biologia Computacional , Secas , Regulação da Expressão Gênica de Plantas , Células Germinativas Vegetais/metabolismo , Germinação , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/fisiologia , Transdução de Sinais
20.
Plant Physiol Biochem ; 141: 407-414, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31228797

RESUMO

Polyphenols are constituents of all higher plants. However, their biosynthesis is often induced when plants are exposed to abiotic stresses, such as drought. The aim of the present work was to determine the phenolic status in the roots of olive trees grown under water deficit conditions. The results revealed that roots of water-stressed plants had a higher content of total phenols. The main compound detected in well-watered olive tree roots was verbascoside. Oleuropein was established as the predominant phenolic compound of water-stressed plants. The oleuropein/verbascoside ratio varied between 0.31 and 6.02 in well-watered and water-stressed plants respectively, which could be a useful indicator of drought tolerance in olive trees. Furthermore, this study is the first to provide experimental evidence showing that luteolin-7-rutinoside, luteolin-7-glucoside and apigenin-7-glucoside were the dominant flavonoid glucosides in olive tree roots and showed the most significant variations under water stress.


Assuntos
Secas , Iridoides/química , Olea/fisiologia , Raízes de Plantas/fisiologia , Antioxidantes/química , Apigenina/química , Flavonoides/química , Glucosídeos/química , Fenol/química , Fenóis/química , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/química , Extratos Vegetais/química , Folhas de Planta/fisiologia , Polifenóis/química , Espectrofotometria Ultravioleta , Estresse Fisiológico , Água
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