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1.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445145

RESUMO

The main goal of growing plants under various photoperiods is to optimize photosynthesis for using the effect of day length that often acts on plants in combination with biotic and/or abiotic stresses. In this study, Brassica juncea plants were grown under four different day-length regimes, namely., 8 h day/16 h night, 12 h day/12 h night, 16 h day/8 h night, and continuous light, and were infected with a necrotrophic fungus Alternaria brassicicola. The development of necroses on B. juncea leaves was strongly influenced by leaf position and day length. The largest necroses were formed on plants grown under a 16 h day/8 h night photoperiod at 72 h post-inoculation (hpi). The implemented day-length regimes had a great impact on leaf morphology in response to A. brassicicola infection. They also influenced the chlorophyll and carotenoid contents and photosynthesis efficiency. Both the 1st (the oldest) and 3rd infected leaves showed significantly higher minimal fluorescence (F0) compared to the control leaves. Significantly lower values of other investigated chlorophyll a fluorescence parameters, e.g., maximum quantum yield of photosystem II (Fv/Fm) and non-photochemical quenching (NPQ), were observed in both infected leaves compared to the control, especially at 72 hpi. The oldest infected leaf, of approximately 30% of the B. juncea plants, grown under long-day and continuous light conditions showed a 'green island' phenotype in the form of a green ring surrounding an area of necrosis at 48 hpi. This phenomenon was also reflected in changes in the chloroplast's ultrastructure and accelerated senescence (yellowing) in the form of expanding chlorosis. Further research should investigate the mechanism and physiological aspects of 'green islands' formation in this pathosystem.


Assuntos
Alternaria/patogenicidade , Mostardeira/microbiologia , Mostardeira/fisiologia , Necrose/microbiologia , Necrose/patologia , Fotossíntese/fisiologia , Doenças das Plantas/microbiologia , Carotenoides/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Fluorescência , Mostardeira/metabolismo , Necrose/metabolismo , Fotoperíodo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia
2.
Plant Mol Biol ; 106(1-2): 109-122, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33638768

RESUMO

KEY MESSAGE: Recombinations between the parental genomes produced a novel mitochondrial genome in the cytoplasmic male sterile Brassica juncea cybrid Og1. A mitochondrial stoichiometric shift greatly reduced the molecule containing male-sterility-inducing orf138 gene leading to reversion to male fertility. An improved, chlorosis-corrected, cytoplasmic male sterile Brassica juncea cybrid Og1 derived from Ogura cytoplasm shows frequent reversion to male fertility. To determine the nature of mitochondrial recombination in the cybrid and to uncover the molecular mechanism of male fertility reversion, we sequenced the mitochondrial genomes of Og1, its isonuclear parental lines (OgRLM and Brassica juncea RLM198) and the revertant line (Og1-rt). Assembly of Og1 mitochondrial genome gave two circular molecules, Og1a (250.999 kbp) and Og1b (96.185 kbp) sharing two large direct repeat regions capable of recombining to form a single circular molecule. Og1a contains all essential mitochondrial genes, but the male-sterility-causing orf138 was uniquely present in Og1b along with 16 other complete or partial genes already represented in Og1a. Eleven and four recombinations between the parental mitochondrial genomes produced the Og1a and the Og1b molecules, respectively. Five genes were duplicated within Og1a, of which trnfM was inherited from both the parents while the other four genes, atp4, cox1 nad4L and trnM, were inherited from RLM198. RFLP analysis revealed that orf138-containing molecules were less abundant than Og1a in the male-sterile plants while og1b bearing molecules were undetectable in the revertant line. However, orf138 transcripts were amplified in RT-PCR and were also detected in northern blots revealing that Og1b molecules are not completely lost in the revertant plants. This is the first report where the mitochondrial genome of a cybrid is compared with its actual parents. The findings are discussed in the light of previous reports on mitochondrial genome recombination in cybrids.


Assuntos
Mitocôndrias/genética , Mostardeira/genética , Mostardeira/fisiologia , Infertilidade das Plantas/genética , Recombinação Genética , DNA Mitocondrial/genética , Fertilidade/genética , Regulação da Expressão Gênica de Plantas , Genes Mitocondriais , Genoma Mitocondrial , Genoma de Planta , Polimorfismo de Fragmento de Restrição
3.
J Chem Ecol ; 47(2): 175-191, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33507456

RESUMO

Plants in the flowering stage need to ensure reproduction by protecting themselves from attack and by preserving interactions with mutualist pollinators. When different plant mutualists are using the same type of cues, such as volatile compounds, attraction of parasitoids and pollinators may trade off. To explore this, we compared volatile emission of Brassica nigra plants in response to single or dual attack on their inflorescences. Additionally, we recorded flower visitation by pollinators and the attraction of parasitoids in the greenhouse and/or field. Brassica nigra were exposed in the flowering stage to one or two of the following three attackers: Brevicoryne brassicae aphids, Pieris brassicae caterpillars, and Xanthomonas campestris pv. raphani bacteria. We found that single attack by caterpillars, and dual attack by caterpillars plus aphids, induced the strongest changes in plant volatile emission. The caterpillars' parasitoid C. glomerata did not exhibit preference for plants exposed to caterpillars only vs. plants exposed to caterpillars plus aphids or plus bacteria. However, the composition of the pollinator community associated with flowers of B. nigra was affected by plant exposure to the attackers, but the total number of pollinators visiting the plants did not change upon attack. We conclude that, when B. nigra were exposed to single or dual attack on their inflorescences, the plants maintained interactions with natural enemies of the insect attackers and with pollinators. We discuss how chemical diversity may contribute to plant resilience upon attack.


Assuntos
Afídeos/fisiologia , Borboletas/fisiologia , Herbivoria , Mostardeira/fisiologia , Polinização , Vespas/fisiologia , Animais , Borboletas/parasitologia , Feminino , Aptidão Genética , Interações Hospedeiro-Parasita , Larva/parasitologia , Larva/fisiologia , Mostardeira/química , Oviposição , Sementes/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/análise
4.
Chemosphere ; 262: 128384, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182105

RESUMO

Arsenic (As) polluted food chain has become a serious issue for the growth and development of humans, animals and plants. Nitric oxide (NO) or silicon (Si) may mitigate As toxicity. However, the combined application of NO and Si in mitigating As uptake and phytotoxicity in Brassica juncea is unknown. Hence, the collegial effect of sodium nitroprusside (SNP), a NO donor and Si application on B. juncea growth, gas exchange parameters, antioxidant system and As uptake was examined in a greenhouse experiment. Arsenic toxicity injured cell membrane as signposted by the elevated level of malondialdehyde (MDA) and hydrogen peroxide (H2O2), thus decreasing the growth of stressed plants. Moreover, As stress negatively affected gas exchange parameters and antioxidative system of plants. However, NO or/and Si alleviated As induced oxidative stress through increasing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), along with thiol and proline synthesis. Furthermore, plants treated with co-application of NO and Si showed improved growth, gas attributes and decreased As uptake under As regimes. The current study highlights that NO and Si synergistically interact to mitigate detrimental effects of As stress through reducing As uptake. Our findings recommend combined NO and Si application in As spiked soils for improvement of plant growth and stress alleviation.


Assuntos
Arsênio/metabolismo , Mostardeira/fisiologia , Óxido Nítrico/química , Silício/química , Poluentes do Solo/metabolismo , Antioxidantes/metabolismo , Arsênio/toxicidade , Ascorbato Peroxidases/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Mostardeira/metabolismo , Doadores de Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Superóxido Dismutase/metabolismo
5.
Plant Physiol Biochem ; 157: 47-59, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33075710

RESUMO

Soil salinity and drought stress (DS) are the massive problem for worldwide agriculture. Both stresses together become more toxic to the plant growth and development. Silicon (Si) being the second most abundant element in the earth's crust, exerts beneficial effects on plants under both stress and non-stress conditions. However, limited information is available to substantiate the beneficial role of Si in delaying the premature leaf senescence and imparting tolerance of mustard (Brassica juncea L.) plants to salinity and DS. Therefore, the present study aimed to explore the role of Si (source K2SiO3) in chlorophyll (Chl) biosynthesis, nutrients uptake, relative water content (RWC), proline (Pro) metabolism, antioxidant system and delaying of premature leaf senescence in mustard plants under sodium chloride (NaCl) and DS conditions. Results of this study show that exogenous Si (1.7 mM) significantly delayed the salt plus DS-induced premature leaf senescence. This was further accompanied by the enhanced nutrients accumulation and activity of chlorophyll metabolizing enzymes [δ-aminolevulinic acid (δ-ALA) dehydratase and porphobilinogen deaminase] and levels of δ-ALA, and Chls a and b and also by decreased the Chl degradation and Chl degrading enzymes (Chlorophyllase, Chl-degrading peroxidase, pheophytinase) activity. Exogenous Si treatment induced redox homoeostasis in B. juncea L. plants, which is evident by a reduced generation of reactive oxygen species (ROS) resulting due to suppressed activity of their generating enzymes (glycolate oxidase and NADPH oxidase) and enhanced defence system. Furthermore, application of Si inhibited the activity of protease and triggered the activity of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) and plasma membrane H+-ATPase activity. In conclusion, all these results reveal that Si could help in the modulation of Chl metabolism, redox hemostasis, and the regulation of nutrients (nitrogen, phosphorus, Si and potassium) uptake in the mustard plants that lead to the postponement of premature leaf senescence under salinity plus DS.


Assuntos
Antioxidantes/fisiologia , Secas , Mostardeira/fisiologia , Salinidade , Silício/farmacologia , Estresse Fisiológico , Homeostase , Mostardeira/efeitos dos fármacos , Folhas de Planta/fisiologia , Plântula
6.
Plant J ; 104(3): 706-717, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32772441

RESUMO

The swollen stem is a determinant of yield for the stem-type vegetable Brassica juncea that is representative of vegetative organ formation. However, the genetic mechanism underlying swollen stem formation and its regulation remains unknown. In this study, we identified a casein kinase 2 ß subunit 1 (CK2B1) and revealed its role in swollen stem formation. Genotyping analysis revealed that a homozygous variation in the CK2B1 promoter is responsible for swollen stem formation, and the promoter activity of CK2B1 was significantly associated with the variations between swollen stem and non-swollen stem types. CK2B1 was exclusively located in the nucleus and expressed in the stem nodes of the plant. Swollen stem formation was blocked when CK2B1 expression was silenced, and induced in a backcross population carrying a swollen stem genotype, which indicates that CK2B1 is required for swollen stem formation. Cell numbers were increased during swollen stem formation and decreased in CK2B1-silenced expression plant, indicating that CK2B1 regulates swollen stem formation via cell division. CK2B1 directly interacted with E2Fa, a regulator of G1/S transition in the cell cycle, in which CK2 phosphorylates E2Fa. Our results revealed that CK2B1 affects swollen stem formation via the control of the cell cycle. These findings help to elucidate the signals that control swollen stem formation and provide a promising molecular target to enhance the yield of vegetative organ formation.


Assuntos
Caseína Quinase II/metabolismo , Mostardeira/fisiologia , Proteínas de Plantas/metabolismo , Caules de Planta/fisiologia , Caseína Quinase II/genética , Ciclo Celular , Fatores de Transcrição E2F/genética , Fatores de Transcrição E2F/metabolismo , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Fosforilação , Filogenia , Proteínas de Plantas/genética , Caules de Planta/citologia , Plantas Geneticamente Modificadas , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas
7.
Plant Physiol Biochem ; 155: 626-636, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32858425

RESUMO

Brassica genus comprises many prominent species valuable for human nutrition including vegetable crops and oilseed. Production of B. juncea is challenged by many abiotic and biotic stresses, Alternaria blight caused by a necrotrophic fungal pathogen Alternaria brassicae is one of the most prominent diseases of cruciferous crops including B. juncea. However, some closely related wild species like Sinapis alba and Camelina sativa exhibit a variable level of resistance towards the pathogen. Apart from the host resistance, intra-specific pathogen variability also influences disease severity to a larger extent. In this study, we identified and isolated two strains of A. brassicae viz ABS1 and ABS2 exhibiting morphological and pathological variability. These isolates were further used to artificially inoculate B. juncea and two of its wild relatives under in-vitro as well as in-vivo conditions to inspect their pathogenicity in a susceptible, a moderately resistant and a highly resistant host. virulent isolate (ABS2) was able to readily establish infection in all the three species whereas the less virulent isolate (ABS1) readily infected susceptible species B. juncea but delayed and mild infection was noticed in tolerant hosts. Variable physiological and molecular host response towards the differential level of virulence of pathogen were established with many confirmatory experiments like DAB staining study, Disease severity index and microscopic analysis. Real-time PCR results confirm that these two isolates induce a variable level of induction in genes PR1 and PDF1.2 within 48 h of the artificial inoculation in B. juncea and its wild relatives.


Assuntos
Alternaria/patogenicidade , Brassicaceae/microbiologia , Doenças das Plantas/microbiologia , Virulência , Brassicaceae/fisiologia , Resistência à Doença , Mostardeira/microbiologia , Mostardeira/fisiologia , Sinapis/microbiologia , Sinapis/fisiologia
8.
Chemosphere ; 260: 127661, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32688327

RESUMO

Phytostabilization of mine soils contaminated by potentially toxic elements (PTEs) requires plants tolerant to PTE toxicity and to the poor soil physico-chemical characteristics of these areas. A pot experiment was carried out to assess the phytostabilization potential of Brassica juncea and Dactylis glomerata in mine soils amended with compost and biochar. Furthermore, the Environmental Risk of the soils and the effects of the phytostabilization process on the microbiological population size and activity in the soils were also determined. According to the Ecological Risk Index (ERI) the soils studied presented "very high risk" and As, Cd and Pb were the target elements for phytostabilization. Both amendments improved soil conditions (e.g., increasing total-N and total organic-C concentrations) and contributed to PTE (Cd, Pb and Zn) immobilization in the soil. Compost showed a more marked effect on soil microbial biomass and nutrients release in soil, which led to higher B. juncea and D. glomerata biomass in compost treated soils. Biochar treatment showed a positive effect only on D. glomerata growth, despite it provoked strong PTE immobilization in both soils. The addition of both amendments resulted in an overall reduction of PTE concentration in the plants compared to the control treatment. In addition, both plant species showed higher accumulation of PTE in the roots than in the shoots (transfer factor<1) independently of the treatment received. Therefore, they can be considered as good candidates for the phytostabilization of PTE contaminated mine soils in combination with organic amendments like biochar and compost.


Assuntos
Biodegradação Ambiental , Mostardeira/fisiologia , Poluentes do Solo/metabolismo , Biomassa , Carvão Vegetal , Compostagem , Dactylis , Raízes de Plantas/química , Solo , Poluentes do Solo/análise
9.
J Biotechnol ; 313: 29-38, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32151644

RESUMO

The involvement of two extremely important signalling molecules, nitric oxide (NO) and abscisic acid (ABA) has been employed by plants to facilitate the adaptive/tolerate response during stressful conditions. However, the interactive role of exogenously applied NO and ABA is very less studied at physiological, biochemical and molecular levels. The present study therefore, evaluated the effects of individual and simultaneous addition of exogenous NO donor SNP (100µM) and ABA (10µM) on photosynthesis, Calvin-Benson cycle enzymes, S-assimilation enzymes, oxidative stress components, and genotoxicity in Brassica juncea cv. Varuna, exposed to polyethylene glycol (PEG)-induced drought stress. Results showed that a loss induced by PEG was significantly surpassed by the application of NO or/and ABA with PEG for chlorophyll content, net photosynthestic rate (Pn), internal CO2 concentration (Ci), stomatal conductance (gs), transpiration rate (Tr), maximum photosystem II (PSII) efficiency (Fv/Fm), actual PSII efficiency (ΦPSII), intrinsic PSII efficiency (Fv´/ Fm´), photochemical quenching (qP), non-photochemical quenching (NPQ), electron transport chain (ETC), ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCo), glyceraldehyde-3-phosphate dehydrogenase (GapDH), phosphoribulokinase (PRK), ATP-sulfurylase (ATP-S), and serine acetyltransferase (SAT) activities. The genomic template stability (GTS) (measured as changes in RAPD profiles) was significantly affected and showed varying degrees of DNA polymorphism, highest in PEG and lowest in PEG + NO and PEG + NO + ABA. Furthermore, the changes in RAPD profiles showed consistent results when compared with various photosynthetic and oxidative parameters. Altogether, this study concluded that supplementation of individual NO and together with ABA was more effective than individual ABA in alleviating PEG-induced drought stress in B. juncea L. seedlings.


Assuntos
Ácido Abscísico/farmacologia , Mostardeira/fisiologia , Óxido Nítrico/farmacologia , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Clorofila/metabolismo , Secas , Fluorescência , Mostardeira/efeitos dos fármacos , Mostardeira/genética , Polietilenoglicóis/farmacologia , Técnica de Amplificação ao Acaso de DNA Polimórfico , Plântula/efeitos dos fármacos , Plântula/fisiologia , Estresse Fisiológico
10.
Plant Cell Environ ; 43(8): 1815-1826, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32096568

RESUMO

Plants can enhance their defence against herbivorous insects by responding to insect egg depositions preceding larval feeding. The similarity of plant responses to insect eggs with those to phytopathogens gave rise to the hypothesis that egg-associated microbes might act as elicitors. We tested this hypothesis by investigating first if elimination of microbes in the butterfly Pieris brassicae changes the responses of Brassica nigra and Arabidopsis thaliana to eggs and larvae of this insect species. An antibiotic treatment of butterflies mitigated the plant transcriptional response to the eggs and the egg-mediated enhancement of the plant's defence against larvae. However, application of cultivated microbial isolates from the eggs onto Arabidopsis thaliana did not enhance the plant's anti-herbivore defence. Instead, application of an egg-associated glandular secretion, which is attaching the eggs to the leaves, elicited the enhancing effect on the plant's defence against larvae. However, this effect was only achieved when the secretion was applied in similar quantities as released by control butterflies, but not when applied in the reduced quantity as released by antibiotic-treated butterflies. We conclude that glandular secretions rather than egg-associated microbes act in a dose-dependent manner as elicitor of the egg-mediated enhancement of the plant's defence against insect larvae.


Assuntos
Arabidopsis/fisiologia , Borboletas/fisiologia , Mostardeira/fisiologia , Óvulo/microbiologia , Animais , Antibacterianos/farmacologia , Arabidopsis/microbiologia , Glândulas Exócrinas/metabolismo , Feminino , Regulação da Expressão Gênica de Plantas , Larva , Mostardeira/microbiologia , Óvulo/efeitos dos fármacos , Óvulo/fisiologia , Folhas de Planta
11.
Chemosphere ; 243: 125361, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31760287

RESUMO

The present experiment unravels how exogenous jasmonic acid regulates photosynthesis, clastogenecity, AsA-GSH cycle and phytochelatins in Brassica juncea L. in response to Pb-subcellular distribution. The plants were evaluated for leaf gas exchange parameters, Fv/Fm, lipid peroxidation, leaf epidermal structures and ABA content. Besides lead accumulation in root, shoot and its subcellular distribution pattern, its role as clastogen and/or aneuploidogen via DNA damage, genome size and ploidy variations, AsA-GSH cycle and quantification of PC2 and PC3 were performed as well. Results revealed that Pb inhibited plant growth, disturbed epidermal and guard cells and consequently worsen leaf gas exchange parameters (E, GH2O, A), Fv/Fm and photosynthetic pigments. For clastogenecity, results revealed considerable DNA damage and analysis for genome size showed that differences between unstressed, Pb-stress and JA application were not significant (P ≤ 0.05), however, ploidy ratio analysis proved partial aneuploidogenic role of Pb. The highest Pb exposure affected AsA-GSH cycle negatively but increased PC2 and PC3 contents uniformly in roots and leaves. Surprisingly, exogenous JA inhibits plant growth under non-stress but positively regulates growth, photosynthesis, AsA-GSH cycle, PC2 and PC3 contents and DNA damage but has no significant effect on variations in total genome size and ploidy under Pb-stress.


Assuntos
Ciclopentanos/metabolismo , Chumbo/toxicidade , Mostardeira/fisiologia , Oxilipinas/metabolismo , Poluentes do Solo/toxicidade , Dano ao DNA , Chumbo/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Mostardeira/metabolismo , Fotossíntese/efeitos dos fármacos , Fotossíntese/fisiologia , Fitoquelatinas/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Poluentes do Solo/metabolismo
12.
Physiol Plant ; 168(2): 490-510, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31794052

RESUMO

Nitric oxide (NO) is a hormone that connects numerous reactions in plant cells under normal and environmental stress conditions. The application of 100 µM NO as sodium nitroprusside (SNP; NO donor) applied individually or in combination with N or S in different combinations (i.e. 100 mg N or S kg-1 soil applied at the time of sowing [100 N + 100S]0d or with split, 50 mg N or S kg-1 soil at the time of sowing and similar dose at 20 d after sowing [50 N + 50S]0d + [50 N + 50S]20d ) was tested to alleviate salt stress in mustard (Brassica juncea L.). Application of 100 µM NO plus split application of N and S more significantly promoted stomatal behavior, photosynthetic and growth performance in the absence of salt stress and maximally alleviated effects of salt stress through increased N- and S-use efficiency, proline and antioxidant system. The combined application of N and S at the time of sowing was lesser effective in promoting photosynthesis and growth under salt or no salt stress conditions in presence or absence of NO. The study suggests that salt stress effects on the photosynthetic performance are mitigated more efficiently when NO was applied together with the split application of N and S given at two stages, and the photosynthetic activity was promoted under salt stress through increased N and S assimilation and antioxidant system. This strategy may be adopted in agricultural system for overcoming salt stress effects on performance of mustard.


Assuntos
Mostardeira/fisiologia , Óxido Nítrico/farmacologia , Nitrogênio/farmacologia , Fotossíntese , Estresse Salino , Enxofre/fisiologia , Mostardeira/efeitos dos fármacos , Estômatos de Plantas/fisiologia
13.
Int J Mol Sci ; 20(18)2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31491923

RESUMO

Metal hyperaccumulating plants should have extremely efficient defense mechanisms, enabling growth and development in a polluted environment. Brassica species are known to display hyperaccumulation capability. Brassica juncea (Indiana mustard) v. Malopolska plants were exposed to trace elements, i.e., cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn), at a concentration of 50 µM and were then harvested after 96 h for analysis. We observed a high index of tolerance (IT), higher than 90%, for all B. juncea plants treated with the four metals, and we showed that Cd, Cu, Pb, and Zn accumulation was higher in the above-ground parts than in the roots. We estimated the metal effects on the generation of reactive oxygen species (ROS) and the levels of protein oxidation, as well as on the activity and gene expression of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The obtained results indicate that organo-specific ROS generation was higher in plants exposed to essential metal elements (i.e., Cu and Zn), compared with non-essential ones (i.e., Cd and Pb), in conjunction with SOD, CAT, and APX activity and expression at the level of encoding mRNAs and existing proteins. In addition to the potential usefulness of B. juncea in the phytoremediation process, the data provide important information concerning plant response to the presence of trace metals.


Assuntos
Antioxidantes/metabolismo , Biodegradação Ambiental , Metais/metabolismo , Mostardeira/fisiologia , Biomassa , Ativação Enzimática , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Metais Pesados/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo
14.
PLoS One ; 14(9): e0222530, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31539385

RESUMO

Quantitative real-time PCR (qRT-PCR) is an efficient method to estimate the gene expression levels but the accuracy of its result largely depends on the stability of the reference gene. Many studies have reported considerable variation in the expression of reference genes (RGs) in different tissue and conditions. Therefore, screening for appropriate RGs with stable expression is crucial for functional analysis of the target gene. Two closely related crucifers Brassica juncea (cultivated) and Camelina sativa (wild) respond differently towards various abiotic and biotic stress where C. sativa exhibits higher tolerance to various stress. Comparative gene expression analysis of the target genes between two such species is the key approach to understand the mechanism of a plant's response to stress. However, using an unsuitable RG can lead to misinterpretation of expression levels of the target gene in such studies. In this investigation, the stability of seven candidate RGs including traditional housekeeping genes (HKGs) and novel candidate RGs were identified across diverse sample sets of B. juncea and C. sativa representing- hormone treated, wounded, Alternaria brassicae inoculated and combination treated samples (exogenous hormone treatment followed by A. brassicae inoculation). In this investigation, we identified stable RGs in both the species and the most suitable RGs to perform an unbiased comparative gene expression analysis between B. juncea and C. sativa. Results revealed that TIPS41 and PP2A were identified as the overall best performing RGs in both the species. However, the most suitable RG for each sample subset representing different condition must be individually selected. In Hormone treated and wounded samples TIPS41 expressed stably in both the species and in A. brassicae inoculated and combination treatment performance of PP2A was the best. In this study, for the first time, we have identified and validated stable reference gene in C. sativa for accurate normalization of gene expression data.


Assuntos
Brassicaceae/genética , Genes de Plantas/genética , Mostardeira/genética , Brassicaceae/fisiologia , Genes Essenciais/genética , Genes Essenciais/fisiologia , Genes de Plantas/fisiologia , Mostardeira/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Transcriptoma
15.
Environ Pollut ; 255(Pt 2): 113257, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546077

RESUMO

Tropospheric ozone is a major atmospheric pollutant; it is phytotoxic and has a strong effect on phytochemicals, which are constitutively present in plant tissues, but also produced de novo in response to stress. It has been shown that ozone exposure can modify volatile phytochemical emissions from leaves, which could disturb interactions between plants and other organisms. However, there is a lack of knowledge on the effects of ozone on floral chemistry. The aim of this study was to determine the effects of two elevated ozone exposure scenarios (80 and 120 ppb during daylight hours for 5 consecutive days) on the floral volatile emissions and floral chemical (molecular size range C6-C20) content of four Brassicaceae species: Sinapis alba, Sinapis arvensis, Brassica napus and Brassica nigra. The results showed that the emissions of individual compounds and their relative contributions to volatile blends are both affected by ozone exposure. In addition, for all four species studied, three diterpenes (neophytadiene, cis-phytol and trans-phytol) were present in significantly lower amounts and a fourth diterpene (hexahydrofarnesyl acetone) in significantly greater amounts in ozone-exposed plants. Consistent effects of ozone exposure on volatile emissions and terpene content were observed for each of the four species studied with no significant effect of exposure level. It appeared that B. napus is the most ozone-sensitive species, whereas B. nigra is the most ozone-tolerant. Since earlier studies have indicated that ratios of phytochemicals can have substantial effects on the efficacy of chemical use by pollinators, these changes may have ecological and biological relevance that should be the focus of further elucidation.


Assuntos
Brassica/fisiologia , Ozônio/toxicidade , Brassica/química , Brassica/efeitos dos fármacos , Brassica napus/química , Brassica napus/efeitos dos fármacos , Mostardeira/fisiologia , Folhas de Planta/efeitos dos fármacos , Polinização/efeitos dos fármacos , Terpenos , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
16.
Ecotoxicol Environ Saf ; 182: 109436, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31325808

RESUMO

Copper (Cu) is an essential yet toxic metal, which holds the ability to induce production of reactive oxygen species (ROS) in living cells resulting in severe abiotic stress. Therefore, the aim of our current study was to investigate the effects of extrinsically added ascorbic acid (AA) on oxidative stress indicators and redox homoeostasis remediators in 7-day-old seedlings and 60-day-old plants of Brassica juncea L. (hyper-accumulator species) subjected to Cu (II) stress. Our findings showed that seed germination ballooned by 55.4% in Cu (II) stressed seedlings upon addition of 50 mg l-1 AA. Copper content accelerated in stressed seedlings and plants; however, a negative interaction was seen upon addition of AA. Both seedlings and plants exposed to Cu (II) accumulated free radicals such as H2O2 and superoxide anion, however, the addition of AA in the growth media decreased H2O2 and superoxide anion generation indicating ROS detoxification. Confocal microscopy also revealed improved cell viability and reduced H2O2 content because of enhanced antioxidant activity upon addition of AA as a protective chelate. Antioxidants such as ascorbate, flavonoids and glutathione rose significantly in Cu (II) stressed seedlings and plants in the presence of AA. Protein content increased by 51.3% and 47.5% in seedlings and plants growing in a binary combination of 100 mg l-1 Cu and AA (75 mg l-1 and 25 mg l-1), respectively. Sharp peaks for stress indicator amino acids such as cysteine and proline were seen in spectral analysis of B. juncea seedlings exposed to Cu (II). Protein thiols increased in plants grown in various binary doses Cu (II) and AA. This study provides sufficient evidence regarding the protective role of ascorbic acid (AA) against ROS and its suggested use as a soil amendment against Cu (II) toxicity in B. juncea.


Assuntos
Ácido Ascórbico/metabolismo , Cobre/toxicidade , Mostardeira/fisiologia , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Cobre/metabolismo , Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Mostardeira/efeitos dos fármacos , Oxirredução , Estresse Oxidativo/fisiologia , Prolina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Superóxido Dismutase/metabolismo
17.
Ecotoxicol Environ Saf ; 181: 491-498, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31229839

RESUMO

Indian mustard (Brassica juncea L.) was more tolerance to Cs than some sensitive plants, such as Arabidopsis thaliana and Vicia faba, and may have a special detoxification mechanism. In this study, the effects on reactive oxygen species (ROS) content, the antioxidant enzyme system and chelation system in Indian mustard were studied by observing different plant physiological responses. In addition, we focused on the analysis of gene regulatory networks related to ROS formation, ROS scavenging system, and other stress-response genes to Cs exposure using a transcriptome-sequencing database. The results showed that ROS and malonaldehyde content in seedlings increased significantly in Cs-treatment groups. The enzyme activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase were increased, and the synthesis of antioxidants glutathione, phytochelatin and metallothionein also increased under Cs treatment. Further analysis showed that ROS formation pathways were primarily the photosynthetic electron transport chain process and photorespiration process in the peroxisome. Antioxidant enzyme systems and the respiratory burst oxidase homolog protein-mediated signal transduction pathway played a key role in ROS scavenging. In summary, one of the mechanisms of tolerance and detoxification of Indian mustard to Cs was that it enhanced the scavenging ability of antioxidant enzymes to ROS, chelated free Cs ions in cells and regulated the expression of related disease-resistant genes.


Assuntos
Antioxidantes/metabolismo , Césio/metabolismo , Mostardeira/fisiologia , Poluentes do Solo/metabolismo , Estresse Fisiológico/genética , Redes Reguladoras de Genes , Mostardeira/enzimologia , Mostardeira/genética , Mostardeira/metabolismo , Oxirredução , Fitoquelatinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plântula/enzimologia , Plântula/metabolismo
18.
BMC Genomics ; 20(1): 348, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31068124

RESUMO

BACKGROUND: Alloplasmic lines, in which the nuclear genome is combined with wild cytoplasm, are often characterized by cytoplasmic male sterility (CMS), regardless of whether it was derived from sexual or somatic hybridization with wild relatives. In this study, we sequenced and analyzed the mitochondrial genomes of five such alloplasmic lines in Brassica juncea. RESULTS: The assembled and annotated mitochondrial genomes of the five alloplasmic lines were found to have virtually identical gene contents. They preserved most of the ancestral mitochondrial segments, and the same candidate male sterility gene (orf108) was found harbored in mitotype-specific sequences. We also detected promiscuous sequences of chloroplast origin that were conserved among plants of the Brassicaceae, and found the RNA editing profiles to vary across the five mitochondrial genomes. CONCLUSIONS: On the basis of our characterization of the genetic nature of five alloplasmic mitochondrial genomes, we speculated that the putative candidate male sterility gene orf108 may not be responsible for the CMS observed in Brassica oxyrrhina and Diplotaxis catholica. Furthermore, we propose the potential coincidence of CMS in alloplasmic lines. Our findings lay the foundation for further elucidation of male sterility gene.


Assuntos
Citoplasma/genética , Genoma Mitocondrial , Mitocôndrias/genética , Mostardeira/genética , Infertilidade das Plantas , Proteínas de Plantas/genética , Regulação da Expressão Gênica de Plantas , Mostardeira/fisiologia , Fases de Leitura Aberta , Filogenia
19.
Environ Pollut ; 249: 598-609, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30933757

RESUMO

Honey bees and brassica plants are co-evolved and due to the peculiar floral characters, mustard (Brassica juncea) plants are strongly dependent on bees for survival. Mustard is one of the most important oilseeds across the world. Insect pests often cause huge economic losses in mustard and their management, especially during flowering stage is very crucial to achieve maximum yield, although this step often displays undesirable effects on the foraging bees. Effects of synthetic pesticides on bees are widely documented and extensively reported. Although the numbers of pesticides/bio-pesticides are widely used in oilseed brassica's, the reports are mostly focused on neonicotinoids. To identify the bee-friendly pesticides, the study was conducted in two tier approach (i.e. laboratory and field conditions) and determined the potential impacts of widely used biopesticides on Asiatic honey bees, Apis cerana Fabricius. The LC50, LC90 and LD50 were determined for four destructive pests and honey bees, to assess their risk against honey bees. In laboratory studies, LC50's of pesticides to the honey bee was in the order of Beauveria bassiana 1.5L (4.79%) > Bacillus thuriengiensis 8SP (1.67%) > Azadirachtin 0.03 EC (1.64%) > Annonin 1 EC (1.22%) > Spinosad 2.5 SC (0.006%) > Imidacloprid 17.8SL (0.005%). Based on three essential risk assessment criteria's (viz., Selectivity ratio, Probit substitution method (%) and Hazard Ratio/Risk quotient); the Azadirachtin, Anonnin, B. bassiana and Bt var. k were found selective, and slightly to moderately toxic to the honeybee; whereas Spinosad and Imidacloprid was found non-selective and dangerous to the bees. Entomopathogenic fungus, Nomuraea rileyi was found absolutely harmless to the bees. In field studies, the relative abundance, foraging rate and foraging speed of honey bees was significantly affected in different treatments even up to 2 days of spraying. Among bio-pesticides, deterrence/repellent effect was, however, strongly observed in Annonin and Spinosad treatments. Significantly higher yield was obtained in Azadirachtin (1.43 t/ha) and Anonin (1.22 t/ha) treated plots. Except Spinosad, remaining bio-pesticides were found selective to the foraging bees, nevertheless considering the efficiency in pest control and higher yield, Azadirachtin 0.03 EC and Annonin 1 EC could be efficiently used in Integrated Pest cum Pollinator Management Programme (IPPM) in oilseed brassica's. The spraying of Spinosad may be discouraged, especially at flowering time.


Assuntos
Abelhas/efeitos dos fármacos , Inseticidas/toxicidade , Limoninas/toxicidade , Macrolídeos/toxicidade , Mostardeira/crescimento & desenvolvimento , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Polinização/efeitos dos fármacos , Animais , Bacillus thuringiensis/patogenicidade , Combinação de Medicamentos , Dose Letal Mediana , Metarhizium/patogenicidade , Mostardeira/fisiologia
20.
Sci Rep ; 9(1): 5626, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30948773

RESUMO

Mustard aphids are a serious problem for Brassica oilseed in India causing up to 90% of the crop damage. It was hypothesized that Aphids migrate into the Indo Gangetic plain (IGP) from hilly regions of every year. Exact source and migration pattern of this pest is unknown till date. During their long range migration they infested various places over IGP, which fall on their way of migration. The wind, blown from the hilly regions helps aphids to migrate. Meteorological parameters play a crucial role in this migration of aphids. In this study, we have done the 24 hours air-mass backward trajectory at 100 m above ground level (agl) to detect the source regions of mustard aphids. We have found that mainly Western Himalayan hilly regions act as the source of mustard aphids for IGPs. The dependence upon the micro-meteorological parameters and population dynamics are analyzed and discussed elaborately in this work. In this study, we have proposed the 'Hop and Fly' behavior of mustard aphid and further discussed how this migrating behavior could help us to reduce the yield loss of Brassica.


Assuntos
Migração Animal/fisiologia , Afídeos/metabolismo , Poluentes Atmosféricos/análise , Animais , Monitoramento Ambiental , Índia , Conceitos Meteorológicos , Mostardeira/fisiologia , Vento
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