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1.
Plants (Basel) ; 11(9)2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35567163

RESUMO

Chloride is an essential nutrient for plants, but high concentrations can be harmful. Silicon ameliorates both abiotic and biotic stresses in plants, but it is unknown if it can prevent cellular increase of chloride. Therefore, we investigated the influx of Cl- ions in two wheat cultivars different in salt sensitivity, by epifluorescence microscopy and a highly Cl--sensitive dye, MQAE, N-[ethoxycarbonylmethyl]-6-methoxy-quinolinium bromide, in absence and presence of potassium silicate, K2SiO3. The Cl--influx was higher in the salt-sensitive cv. Vinjett, than in the salt-tolerant cv. S-24, and silicate pre-treatment of protoplasts inhibited the Cl--influx in both cultivars, but more in the sensitive cv. Vinjett. To investigate if the Cl--transporters TaCLC1 and TaNPF2.4/2.5 are affected by silicate, expression analyses by RT-qPCR were undertaken of TaCLC1 and TaNPF 2.4/2.5 transcripts in the absence and presence of 100 mM NaCl, with and without the presence of K2SiO3. The results show that both transporter genes were expressed in roots and shoots of wheat seedlings, but their expressions were differently affected by silicate. The TaNPF2.4/2.5 expression in leaves was markedly depressed by silicate. These findings demonstrate that less chloride accumulates in the cytosol of leaf mesophyll by Si treatment and increases salt tolerance.

2.
Physiol Mol Biol Plants ; 27(9): 2101-2114, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34629781

RESUMO

Plant growth-promoting rhizobacteria (PGPR) represent a set of microorganisms that play significant role in improving plant growth and controlling the phytopathogens. Unpredictable performance after the application of PGPR has been observed when these were shifted from in-vitro to in-vivo conditions due to the prevalence of various abiotic stress conditions. During growing period, the potato crop is subjected to a combination of biotic and abiotic stresses. Rhizoctonia solani, a soil-borne plant pathogen, causes reduced vigor and yield of potato crop worldwide. In the current study, multi-stress-tolerant rhizobacterial strain, Bacillus subtilis PM32, was isolated from field-grown potato with various plant growth promoting (PGP) traits including zinc and potassium solubilization, biological nitrogen fixation, ammonia and siderophore, as well as extracellular enzyme productions (cellulase, catalase, amylase, protease, pectinase, and chitinase). The strain PM32 exhibited a distinct potential to support plant growth by demonstrating production of indole-3-acetic acid (102.6 µM/mL), ACC-deaminase activity (1.63 µM of α-ketobutyrate/h/mg protein), and exopolysaccharides (2.27 mg/mL). By retarding mycelial growth of R. solani the strain PM32 drastically reduced pathogenicity of R. solani. The strain PM32 also suppressed the pathogenic activity significantly by impeding mycelial expansion of R. solani with inhibition co-efficient of 49.87. The B. subtilis PM32 also depicted significant tolerance towards salt, heavy metal (Pb), heat and drought stress. PCR based amplification of ituC and acds genes coding for iturin and ACC-deaminase activity respectively indicated potential of strain PM32 for lipopeptides production and ACC deaminase enzyme activity. Results of both in-vitro and pot experiments under greenhouse conditions depicted the efficiency of B. subtilis PM32 as a promising bio-control agent for R. solani infection together with enhanced growth of potato plants as deciphered from biomass accumulation, chlorophyll a, b, and carotenoid contents. Therefore, it was envisioned that application of indigenous multi-stress tolerant PGPR may serve to induce biotic and abiotic stress tolerance in crops/plants for pathogen control and sustainable global food supply. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01067-2.

3.
Environ Sci Pollut Res Int ; 28(39): 55140-55153, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34128171

RESUMO

Copper (Cu) is a heavy metal which is being used widely in the industry and agriculture. However, the overuse of Cu makes it a common environmental pollutant. In order to investigate the testicular toxicity of Cu, the pigs were divided into three groups and were given Cu at 10 (control), 125, and 250 mg/kg body weight, respectively. The feeding period was 80 days. Serum hormone results showed that Cu exposure decreased the concentrations of follicular stimulating hormone (FSH) and luteinizing hormone (LH) and increased the concentration of thyroxine (T4). Meanwhile, Cu exposure upregulated the expression of Cu transporter mRNA (Slc31a1, ATP7A, and ATP7B) in the testis, leading to increase in testicular Cu and led to spermatogenesis disorder. The Cu exposure led to an increased expression of antioxidant-related mRNA (Gpx4, TRX, HO-1, SOD1, SOD2, SOD3, CAT), along with increase in the MDA concentration in the testis. In LG group, the ROS in the testis was significantly increased. Furthermore, the apoptotic-related mRNA (Caspase3, Caspase8, Caspase9, Bax, Cytc, Bak1, APAF1, p53) and protein (Active Caspase3) and the autophagy-related mRNA (Beclin1, ATG5, LC3, and LC3B) expression increased after Cu exposure. The mitochondrial membrane potential in the testicular tissue decreased, while the number of apoptotic cells increased, as a result of oxidative stress. Overall, our study indicated that the Cu exposure promotes testicular apoptosis and autophagy by mediating oxidative stress, which is considered as the key mechanism causing testicular degeneration as well as dysfunction.


Assuntos
Cobre , Testículo , Animais , Apoptose , Autofagia , Cobre/toxicidade , Masculino , Estresse Oxidativo , Suínos
5.
Environ Sci Pollut Res Int ; 28(33): 45353-45363, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33864214

RESUMO

We studied the physio-biochemical involvement of exogenous signaling compounds, glutathione and putrescine (alone and in combination), on three contrasting genotypes (cvs. Shiralee, Rainbow, and Dunkled) of canola (Brassica napus L.) of plants exposed to chromium stress. Seeds were germinated in Cr-contaminated soil (0 and 50 µg/g Cr6+), and both signaling compounds were applied as a foliar spray to 20-day-old plants. Changes in root, stem, and leaf nitro-oxidative metabolism, endogenous GSH level, secondary metabolites, and mineral nutrients were investigated from 60-day-old plants. Exposure to Cr6+ increased stem GSH and NO concentrations in all cultivars. Maximum root Cr6+ bioaccumulation was recorded in cv. Rainbow and the least in cv. Shiralee. Also, Cr6+ stress decreased number and weight of seeds and pod length. Disturbances in root and shoot mineral profile were evident; however, its magnitude varied in all cultivars. The exogenous GSH improved root and shoot P, Fe, S, and Zn concentrations; however, the effect was cultivar specific. Leaf endogenous GSH was increased by exogenous GSH while NO levels remained unaffected. The GSH application also promoted shoot Cr6+ bioaccumulation while PUT application caused a recovery in seed number and seed weight. Both PUT and GSH differentially affected tissue-specific secondary metabolite profile. Overall, the exogenous GSH was much more effective in alleviating the Cr+6 toxicity in canola.


Assuntos
Brassica napus , Antioxidantes , Brassica napus/genética , Cromo , Glutationa , Minerais , Putrescina
6.
Physiol Mol Biol Plants ; 27(2): 297-312, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33707870

RESUMO

Cadmium (Cd) in soil-plant system can abridge plant growth by initiating alterations in root zones. Hydroponics and rhizoboxes are useful techniques to monitor plant responses against various natural and/or induced metal stresses. However, soil based studies are considered more appropriate in order to devise efficient food safety and remediation strategies. The present research evaluated the Cd-mediated variations in elemental dynamics of rhizospheric soil together with in planta ionomics and morpho-physio-biochemical traits of two differentially Cd responsive maize cultivars. Cd-sensitive (31P41) and Cd-tolerant (3062) cultivars were grown in pots filled with 0, 20, 40, 60 and 80 µg/kg CdCl2 supplemented soil. The results depicted that the maize cultivars significantly influenced the elemental dynamics of rhizosphere as well as in planta mineral accumulation under applied Cd stress. The uptake and translocation of N, P, K, Ca, Mg, Zn and Fe from rhizosphere and root cell sap was significantly higher in Cd stressed cv. 3062 as compared to cv. 31P41. In sensitive cultivar (31P41), Cd toxicity resulted in significantly prominent reduction of biomass, leaf area, chlorophyll, carotenoids, protein contents as well as catalase activity in comparison to tolerant one (3062). Analysis of tolerance indexes (TIs) validated that cv. 3062 exhibited advantageous growth and efficient Cd tolerance due to elevated proline, phenolics and activity of antioxidative machinery as compared to cv. 31P41. The cv. 3062 exhibited 54% and 37% less Cd bio-concentration (BCF) and translocation factors (TF), respectively in comparison to cv. 31P41 under highest Cd stress regime. Lower BCF and TF designated a higher Cd stabilization by tolerant cultivar (3062) in rhizospheric zone and its potential use in future remediation plans.

8.
Microsc Res Tech ; 84(7): 1522-1530, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33608993

RESUMO

Advanced research, development, and application of silver nanoparticles is proceeding in recent times due to their incredible utilization in various fields. Present study was focused on the production, characterization, and antifungal activities of silver nanoparticles (AgNPs). An environment friendly extracellular biosynthetic approach was adopted to produce the AgNPs by using bacteria, fungi, and sugarcane husk. Agents used for reduction of silver to nanoparticles were taken from culture filtrate of plant growth promoting bacteria, Fusarium oxysporum and supernatant extract of sugarcane husk. Nanoparticles were also characterized by scanning electron microscopy (SEM). Synthesis of colloidal AgNPs was observed by UV-Visible diffused reflectance spectroscopy (UV-Vis DRS). Primary peak of surface plasmon resonance band was noticed around 339.782, 336.735, and 338.258 nm for bacterial, fungal, and sugarcane husk produced AgNPs. Structure of all biologically produced nanoparticles were crystalline cubic with nano size of 45.41, 49.06, and 42.75 nm for bacterial, fungal, and sugarcane husk-based nanoparticles, respectively as calculated by Debye-Scherrer equation using XRD. Fourier transform infrared spectroscopy (FTIR) analysis revealed the presence of various compounds that aid in the reduction, capping, and stability of AgNPs. The antifungal activity of AgNPs was also investigated for sugarcane fungal pathogens Colletotricum falcatum and Fusarium moniliforme. All nanoparticles exhibit prominent antifungal activities. Maximum zone of fungal inhibition was noticed about 18, 19, and 21 mm for C. falcatum while 21, 20, and 24 mm for F. moniliforme in case of bacterial, fungal, and plant-based nanoparticles (15 ppm), respectively. Best fungal inhibition was observed under application of sugarcane husk based AgNPs. Moreover, biologically produced AgNPs responded better towards the suppression of F. moniliforme in comparison to C. falcatum. Mentioned sources in present study can be ecofriendly nano-factories for biosynthesis of AgNPs and mankind should benefit from their commercial application.


Assuntos
Nanopartículas Metálicas , Saccharum , Antibacterianos , Fusarium , Extratos Vegetais , Prata/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Ecotoxicol Environ Saf ; 208: 111584, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396107

RESUMO

Cadmium (Cd) is highly toxic for plant metabolic processes even in low concentration due to higher retention rates, longer half-life and non-biodegradable nature. The current study was designed to assess the bioremediation potential of Cd tolerant PGPR, Serratia sp. CP-13 together with two differentially Cd tolerant maize cultivars (MMRI-Yellow, Sahiwal-2002) selected amongst ten cultivars after screening. The maize cultivars were grown under different Cd treatments (0, 6, 12, 18, 24, 30 µM) in Petri plates both with and without Serratia sp. CP-13 inoculation. Treated plants were analyzed for their biomass accumulation, chlorophylls, carotenoids, proline, anthocyanin, protein, malondialdehyde (MDA), H2O2 as well as for antioxidants (POD, SOD, CAT) and mineral elements (Ca, Mg, Zn, K, Fe, Na, Cd). The maize cultivar MMRI-Yellow (tolerant) and Sahiwal-2002 (sensitive) exhibited significant reduction in leaf area, nutrient contents, plant biomass, activity of antioxidants, total proteins, photosynthetic pigments as well as flavonoids with increased production of H2O2, proline, MDA and relative membrane permeability (RMP) under Cd stress. However, this reduction was cultivar specific and recorded higher in cv. Sahiwal-2002 as compared to MMRI-Yellow. Application of Serratia sp. CP-13 significantly augmented plant biomass, photosynthetic pigments, antioxidative machinery, as well as flavonoids and proline while diminishing H2O2, RMP MDA production even under Cd stress in studied cultivars. Furthermore, CP-13 inoculation assisted the Cd stressed plants to sustain an optimal level of essential nutrients (Ca, Mg, Zn, K, Fe) except for Na and Cd which responded antagonistically. It was inferred that both inoculated maize cultivars exhibited better health and metabolism but substantial Cd tolerance was acquired by the sensitive cv. Sahiwal-2002 than the tolerant cv. MMRI-Yellow under applied Cd regimes. Furthermore, studied maize cultivars depicted maximum Cd tolerance in order of 30 < 24 < 18 < 12 < 6 < 0 µM Cd treatments under Serratia sp. CP-13 inoculation. Findings of current work highlighted the importance of Serratia sp. CP-13 and its inoculation impact on morpho-physio-biochemical attributes of maize growth under Cd dominant environment, which is likely an addition towards efficient approaches for bacterially-assisted Cd bioremediation and minimal Cd retention in edible plant parts.


Assuntos
Cádmio/toxicidade , Serratia/fisiologia , Poluentes do Solo/toxicidade , Zea mays/fisiologia , Antioxidantes/metabolismo , Biodegradação Ambiental , Transporte Biológico , Biomassa , Cádmio/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Fotossíntese , Folhas de Planta/metabolismo , Serratia/metabolismo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Zea mays/metabolismo , Zea mays/microbiologia
10.
Environ Sci Pollut Res Int ; 28(21): 27376-27390, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33507502

RESUMO

Contamination of soils with heavy metals (HMs) caused serious problems because plants tend to absorb HMs from the soil. In view of HM hazards to plants as well as agro-ecosystems, we executed this study to assess metal toxicity to mung bean (Vigna radiata) plants cultivated in soil with six treatment levels of cadmium (Cd) and nickel (Ni) and to find metal tolerant variety, i.e., M-93 (V1) and M-1(V2) with multifarious plant biochemical and physiological attributes. Increasing doses of Cd and Ni inhibited plant growth and photosynthesis and both varieties showed highly significant differences in the morpho-physiological attributes. V2 showed sensitivity to Cd and Ni treatments alone or in combination. Tolerance indices for attributes presented a declined growth of Vigna plants under HM stress accompanied by highly significant suppression in gas exchange characteristics. Of single element applications, the adverse effects on mung bean were more pronounced in Cd treatments. V1 showed much reduction in photosynthesis attributes except sub-stomatal CO2 concentration in all treatments compared to V2. The yield attributes, i.e., seed yield/plant and 100-seed weight, were progressively reduced in T5 for both varieties. In combination, we have observed increased mobility of Cd and Ni in both varieties. The results showed that water use efficiency (WUE) generally increased in all the treatments for both varieties compared to control. V2 exhibited less soluble sugars and free amino acids compared to V1 in all the treatments. Similarly, we recorded an enhanced total free amino acid contents in both varieties among all the metal treatments against control plants. We conclude that combinatorial treatment proved much lethal for Vigna plants, but V1 performed better than V2 in counteracting the adverse effects of Cd and Ni.


Assuntos
Vigna , Cádmio , Ecossistema , Homeostase , Níquel , Fotossíntese
11.
Environ Sci Pollut Res Int ; 28(22): 27542-27554, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33511536

RESUMO

Chromium (Cr), being a persistent toxic heavy metal, triggered the retardation of plant's metabolic processes by initiating changes in rhizospheric zone. Current study focused the Cr accumulation potential of two tomato (Solanum lycopersicum Mill.) cultivars through alterations of rhizospheric pH and exudation of organic acids together with plant's ionomics and morpho-physiological responses. Four-week-old seedlings of tomato cultivars (cv. Nakeb and cv. Nadir) were maintained in hydroponic solutions supplemented with 0, 100, 200, and 300 mg/L K2Cr2O7 and a start pH of 6.0. The pH of the growth medium was monitored twice a day up to 6 days as well as mineral contents and morpho-physiological attributes were recorded by harvesting half of plants after 1 week. The remaining half plants were shifted to rhizoboxes for the collection of root exudates. After 6 days, cv. Nakeb exhibited medium acidification by 0.7 units while cv. Nadir showed basification by 0.6 units under 300 mg/L treatment. Increase in applied Cr levels enhanced the root and shoot Cr accumulation in both cultivars with concomitant reduction in growth and accumulation of nutrients (Fe, Zn, K, Mg, and Ca). However, this reduction in biomass and nutrient acquisition was predominant in cv. Nakeb as compared to cv. Nadir. The release of organic acid exudates (citric, acetic, maleic, tartaric, and oxalic acids) was also recorded higher in cv. Nadir at 300 mg/L applied Cr level. This enhanced production of organic acids caused greater retention of mineral nutrients and Cr in cv. Nadir, probably due to growth medium basification. Enhanced exudations of di- and tri- carboxylic organic acids together with accumulation of mineral nutrients are the physiological and biochemical indicators which confer this genotype a better adaptation to Cr polluted biotic systems. Furthermore, it was perceived that organic acid and rhizospheric pH variation response by studied tomato cultivars under Cr stress is an important factor to be considered in food safety and metal remediation programs.


Assuntos
Lycopersicon esculentum , Poluentes do Solo , Cromo , Concentração de Íons de Hidrogênio , Raízes de Plantas/química , Poluentes do Solo/análise
12.
Dose Response ; 19(4): 15593258211066693, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34987342

RESUMO

The poultry sector is one of the most vibrant segments of the agriculture industry of Pakistan. In addition to different infections, ammonia (NH3) production from litter material of broiler is the most harmful pollutant and causes serious threats for the environment. To overcome this problem, different methods are proposed assuring poultry bird's health and production. This study was carried out to evaluate the effect of toxic levels of NH3 on the haematology and serum proteins of broiler birds and its amelioration by using different modifiers. The recovery of Escherichia coli (E. coli) from liver and spleen of broiler birds was also carried out. A total of 100 birds were divided into 5 separate groups (groups A-D). The groups C, D and E were treated with potassium aluminium sulphate, aluminium silicate and Yucca schidigera plant extract, respectively. Blood and tissue samples were collected after slaughtering the birds at 42 days of age. This study revealed increased RBC, total leucocyte count, Hb and heterophils percentage. Serum proteins were decreased in Yucca-treated and potassium aluminium sulphate-treated groups. This study concluded that NH3 production was reduced by the application of different modifiers, and these modifiers also neutralized the changes in blood parameters induced by NH3.

13.
Plant Physiol Biochem ; 157: 23-37, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33069978

RESUMO

Soil contamination with toxic heavy metals [such as cadmium (Cd)] is becoming a serious global problem due to rapid development of social economy. Silicon (Si), being an important fertilizer element, has been found effective in enhancing plant tolerance against biotic and abiotic stresses. The present study investigated the extent to which different levels of Si modulated the Cd tolerance of Ajwain (Trachyspermum ammi L.) seedlings when maintained in artificially Cd spiked regimes. A pot experiment was conducted under controlled conditions for four weeks, by using sand, mixed with different levels of Cd i.e., 0, 1.5 and 3 mM together with the application of Si at 0, 1.5 and 3 mM levels to monitor different growth, gaseous exchange, oxidative stress, antioxidative responses, minerals accumulation, organic acid exudation patterns of T. ammi seedlings. Our results depicted that Cd addition to growth medium significantly decreased plant growth and biomass, gaseous exchange attributes and minerals uptake by T. ammi seedlings as compared to the plants grown without addition of Cd. However, Cd toxicity boosted the production of reactive oxygen species (ROS) by increasing the contents of malondialdehyde (MDA), which is the indication of oxidative stress in T. ammi seedlings and was also manifested by hydrogen peroxide (H2O2) contents and electrolyte leakage to the membrane bounded organelles. Although, activities of various antioxidative enzymes like superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) initially increased up to a Cd level of 1.5 mM but were significantly diminished at the highest Cd level of 3 mM. Results revealed that the anthocyanin and soluble proteins contents were decreased in seedlings grown under elevating Cd levels but increased the Cd accumulation of T. ammi roots and shoots. The negative impacts of Cd injury were reduced by the application of Si which increased plant growth and biomass, improved photosynthetic apparatus, antioxidant enzymes, minerals uptake together with diminished exudation of organic acids as well as oxidative stress indicators in roots and shoots of T. ammi by decreasing Cd retention in different plant parts. Research findings, therefore, suggested that Si application can ameliorate Cd toxicity in T. ammi seedlings and resulted in improved plant growth and composition under metal stress as depicted by balanced exudation of organic acids.


Assuntos
Apiaceae/metabolismo , Cádmio/toxicidade , Silício/farmacologia , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Peróxido de Hidrogênio , Estresse Oxidativo , Raízes de Plantas/metabolismo , Plântula/metabolismo
14.
Physiol Mol Biol Plants ; 26(9): 1787-1797, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32943816

RESUMO

A pot experiment was conducted to examine the effect of foliar application of various levels of ZnSO4 on wheat (Triticum aestivum L.) under cadmium (Cd) stress. Seeds of two wheat varieties i.e., Ujala-2016 and Anaj-2017 were sown in sand filled plastic pots. Cadmium (CdCl2) stress i.e., 0 and 0.5 mM CdCl2 was applied in full strength Hoagland's nutrient solution after 4 weeks of seed germination. Foliar spray of varying ZnSO4 levels i.e., 0, 2, 4, 6 and 8 mM was applied after 2 weeks of CdCl2 stress induction (of 6 week old plants). After 3 weeks of foliar treatment leaf samples of 9 week old wheat plants were collected for the determination of changes in various growth and physiobiochemical attributes. Results obtained showed that cadmium stress (0.5 mM CdCl2) significantly decreased shoot and root fresh and dry weights, shoot and root lengths, yield attributes, chlorophyll a contents and total phenolics, while increased hydrogen peroxide (H2O2), total soluble proteins, free proline, glycinebetaine (GB) contents, and activities of antioxidant enzymes i.e., catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD). Foliar application of varying ZnSO4 levels significantly increased various growth attributes, chlorophyll b contents, H2O2, free proline, GB and activities of antioxidant enzymes i.e., CAT, POD and APX, while decreased relative water contents and total phenolics under Cd stress or non stress conditions. Furthermore, both wheat varieties showed differential response under Cd stress and towards foliar application of ZnSO4 e.g., wheat var. Ujala-2016 was higher in shoot dry weight, root length, root fresh and dry weights, total leaf area per plant, 100 grains weight, number of tillers per plant, chlorophyll b, hydrogen peroxide (H2O2), activities of APX, POD, glycinebetaine and leaf free proline contents, while var. Anaj-2017 exhibited high shoot fresh weight, grain yield per plant, no. of grains per plant, chlorophyll contents, chlorophyll a/b ratio, total phenolics, MDA and total soluble protein contents under cadmium stress or non stress conditions.

15.
Plant Physiol Biochem ; 155: 815-827, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32882619

RESUMO

Cadmium is a phytotoxic metal which threatens the global food safety owing to its higher retention rates and non-biodegradable nature. Optimal study of microbe-assisted bioremediation is a potential way to minimize the adversities of Cd on plants. Current study was aimed to isolate, identify and characterize Cd tolerant PGPBs from industrially contaminated soil and to evaluate the potential of plant-microbe synergy for the growth augmentation and Cd remediation. The Acinetobacter sp. SG-5, identified through 16S rRNA gene sequence analysis, was able to tolerate 1000 mg/l of applied Cd stress and ability of in vitro indole-3-acetic acid production, phosphate solubilization, as well as 1-aminocyclopropane-1-carboxylic acid deaminase activity. A Petri plate experiment was designed to investigate the impact of Acinetobacter sp. SG-5 on applied Cd toxicity (0, 6, 12, 18, 24, 30 µM) in maize cultivars (3062-Cd tolerant, 31P41-Cd susceptible). Results revealed that non-inoculated maize plants were drastically affected with applied Cd treatments for growth, antioxidants and mineral ions acquisition predominantly in susceptible cultivar (31P41). PGPB inoculation positively influenced the maize growth by enhanced anti-oxidative potential coupled with optimum level of nutrients (K, Ca, Mg, Zn). Analysis of morpho-physio-biochemical traits after PGPB application revealed that substantial Cd tolerance was acquired by susceptible cv. 31P41 than tolerant cv. 3062 under applied Cd regimes. Research outcomes may be important for understanding the growth responses of Cd susceptible and tolerant maize cultivars under Acinetobacter sp. SG-5 inoculation and likely to provide efficient approaches to reduce Cd retention in edible plant parts and/or Cd bioremediation.


Assuntos
Acinetobacter , Antioxidantes/fisiologia , Cádmio/toxicidade , Poluentes do Solo/toxicidade , Zea mays/fisiologia , Biodegradação Ambiental , Raízes de Plantas/química , RNA Ribossômico 16S , Zea mays/efeitos dos fármacos , Zea mays/microbiologia
16.
Plant Physiol Biochem ; 152: 90-99, 2020 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-32408178

RESUMO

Rapid industrialization is the main reason of heavy metals contamination of soil colloids and water reservoirs. Heavy metals are persistent inorganic pollutants; deleterious to plants, animals and human beings because of accumulation in food chain. The aim of the current work was to evaluate the role of indole acetic acid (IAA), exopolysaccharide (EPS) and ACC-deaminase producing plant growth promoting rhizobacteria (PGPR) i.e .B. gibsonii PM11 and B. xiamenensis PM14 in metal phytoremediation of metals, their survival and plant growth promotion potential in metal polluted environment as well as alterations in physio-biochemical responses of inoculated L. usitatissimum plants towards heavy metal toxicity. Two bacterial strains Bacillus gibsonii (PM11) and Bacillus xiamenensis (PM14), previously isolated from sugarcane's rhizosphere, were screened for metal tolerance (50 mg/l to 1000 mg/l) and plant growth promoting traits like IAA, ACC-deaminase, EPS production and nitrogen fixing ability under metal stress. The response of flax plant (Linum usitatissimum L.) was analyzed in a pot experiment containing both industrially contaminated and non-contaminated soils. Experiment was comprised of six different treatments, each with three replicates. At the end of the experiment, role of metal tolerant plant growth promoting bacterial inoculation was elucidated by analyzing the plant growth parameters, chlorophyll contents, antioxidative enzymes, and metal uptake both under standard and metal contaminated rhizospheres. Results revealed that root and shoot length, plant's fresh and dry weight, proline content, chlorophyll content, antioxidant enzymatic activity was increased in plants inoculated with plant growth promoting bacteria as compared to non-inoculated ones both in non-contaminated and industrial contaminated soils. In current study, inoculation of IAA, EPS and ACC-deaminase producing bacteria enhances plant growth and nutrient availability by minimizing metal-induced stressed conditions. Moreover, elevated phytoextraction of multi-metals from industrial contaminated soils by PGPR inoculated L. usitatissimum plants reveal that these strains could be used as sweepers in heavy metals polluted environment.

17.
Plant Physiol Biochem ; 151: 640-649, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32339911

RESUMO

Sustainability in crop production has emerged as one of the most important concerns of present era's agricultural systems. Plant growth promoting bacteria (PGPB) has been characterized as a set of microorganisms used for enhancing plant growth and a tool for biological control of phytopathogens. However, the inconsistent performance of these bacteria from laboratory/greenhouse to field level has emerged due to prevailing abiotic stresses in fields. Sugarcane crop encounters a combination of biotic and abiotic stresses during its long developmental stages. Nevertheless, the selection of antagonistic PGPB with abiotic stress tolerance would be beneficial for end-user by the successful establishment of product with required effects under field conditions. Stress tolerant Bacillus xiamenensis strain (PM14) isolated from the sugarcane rhizosphere grown in the fields was examined for various PGP activities, enzyme assays, and antibiotic resistance. Strain was screened for in vitro tolerance against drought, salinity, heat stress, and heavy metal toxicity. Inhibition co-efficient of B. xiamenensis PM14 was also calculated against six phyto-pathogenic fungi, including Colletotrichum falcatum (53.81), Fusarium oxysporum (68.24), Fusarium moniliforme (69.70), Rhizoctonia solani (71.62), Macrophomina phaseolina (67.50), and Pythium splendens (77.58). B. xiamenensis is reported here for the first time as the rhizospheric bacterium which possesses resistance against 12 antibiotics and positive results for all in vitro PGP traits except HCN production. Role of 1-aminocyclopropane-1-carboxylate deaminase in the amelioration of biotic and abiotic stress was also supported by the amplification of acds gene. Moreover, in vitro and in vivo experiments revealed B. xiamenensis as the potential antagonistic PGPR and bio-control agent. Results of greenhouse experiment against sugarcane red rot indicated that inoculation of B. xiamenensis to sugarcane plants could suppress the disease symptoms and enhance plant growth. Augmented production of antioxidative enzymes and proline content may lead to the induced systemic resistance against red rot disease of sugarcane. Thus, the future application of native multi-stress tolerant bacteria as bio-control agents in combination with current heat, drought, salinity, and heavy metal tolerance strategy could contribute towards the global food security.


Assuntos
Bacillus , Resistência à Doença , Saccharum , Bacillus/fisiologia , Resistência à Doença/fisiologia , Fungos/fisiologia , Doenças das Plantas/microbiologia , Saccharum/microbiologia
18.
Biomolecules ; 10(4)2020 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-32290389

RESUMO

Soil and water contamination from heavy metals and metalloids is one of the most discussed and caused adverse effects on food safety and marketability, crop growth due to phytotoxicity, and environmental health of soil organisms. A hydroponic investigation was executed to evaluate the influence of citric acid (CA) on copper (Cu) phytoextraction potential of jute (Corchorus capsularis L.). Three-weeks-old seedlings of C. capsularis were exposed to different Cu concentrations (0, 50, and 100 µM) with or without the application of CA (2 mM) in a nutrient growth medium. The results revealed that exposure of various levels of Cu by 50 and 100 µM significantly (p < 0.05) reduced plant growth, biomass, chlorophyll contents, gaseous exchange attributes, and damaged ultra-structure of chloroplast in C. capsularis seedlings. Furthermore, Cu toxicity also enhanced the production of malondialdehyde (MDA) which indicated the Cu-induced oxidative damage in the leaves of C. capsularis seedlings. Increasing the level of Cu in the nutrient solution significantly increased Cu uptake by the roots and shoots of C. capsularis seedlings. The application of CA into the nutrient medium significantly alleviated Cu phytotoxicity effects on C. capsularis seedlings as seen by plant growth and biomass, chlorophyll contents, gaseous exchange attributes, and ultra-structure of chloroplast. Moreover, CA supplementation also alleviated Cu-induced oxidative stress by reducing the contents of MDA. In addition, application of CA is helpful in increasing phytoremediation potential of the plant by increasing Cu concentration in the roots and shoots of the plants which is manifested by increasing the values of bioaccumulation (BAF) and translocation factors (TF) also. These observations depicted that application of CA could be a useful approach to assist Cu phytoextraction and stress tolerance against Cu in C. capsularis seedlings grown in Cu contaminated sites.


Assuntos
Cloroplastos/ultraestrutura , Ácido Cítrico/farmacologia , Cobre/toxicidade , Corchorus/crescimento & desenvolvimento , Corchorus/fisiologia , Plântula/fisiologia , Estresse Fisiológico/efeitos dos fármacos , Antioxidantes/metabolismo , Biodegradação Ambiental/efeitos dos fármacos , Biomassa , Clorofila/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Corchorus/efeitos dos fármacos , Corchorus/ultraestrutura , Gases/metabolismo , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Análise de Componente Principal , Plântula/efeitos dos fármacos , Plântula/ultraestrutura
19.
Plants (Basel) ; 9(2)2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32098385

RESUMO

The present experiment was carried out to study the influences of exogenously-applied nitric oxide (NO) donor sodium nitroprusside (SNP) and hydrogen peroxide (H2O2) as seed primers on growth and yield in relation with different physio-biochemical parameters, antioxidant activities, and osmolyte accumulation in wheat plants grown under control (100% field capacity) and water stress (60% field capacity) conditions. During soaking, the seeds were covered and kept in completely dark. Drought stress markedly reduced the plant growth, grain yield, leaf photosynthetic pigments, total phenolic content (TPC), total soluble proteins (TSP), leaf water potential (Ψw), leaf turgor potential (Ψp), osmotic potential (Ψs), and leaf relative water content (LRWC), while it increased the activities of enzymatic antioxidants and the accumulation of leaf ascorbic acid (AsA), proline (Pro), glycine betaine (GB), malondialdehyde (MDA), and H2O2. However, seed priming with SNP and H2O2 alone and in combination mitigated the deleterious effects of water stress on growth and yield by improving the Ψw, Ψs, Ψp, photosynthetic pigments, osmolytes accumulation (GB and Pro), TSP, and the antioxidative defense mechanism. Furthermore, the application of NO and H2O2 as seed primers also reduced the accumulation of H2O2 and MDA contents. The effectiveness was treatment-specific and the combined application was also found to be effective. The results revealed that exogenous application of NO and H2O2 was effective in increasing the tolerance of wheat plants under drought stress in terms of growth and grain yield by regulating plant-water relations, the antioxidative defense mechanism, and accumulation of osmolytes, and by reducing the membrane lipid peroxidation.

20.
Physiol Mol Biol Plants ; 26(12): 2417-2433, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33424156

RESUMO

Cadmium (Cd) is highly toxic metal for plant metabolic processes even in low concentration due to its longer half-life and non-biodegradable nature. The current study was designed to assess the bioremediation potential of a Cd-tolerant phytobeneficial bacterial strain Bacillus sp. SDA-4, isolated, characterized and identified from Chakera wastewater reservoir, Faisalabad, Pakistan, together with spinach (as a test plant) under different Cd regimes. Spinach plants were grown with and without Bacillus sp. SDA-4 inoculation in pots filled with 0, 5 or 10 mg kg-1 CdCl2-spiked soil. Without Bacillus sp. SDA-4 inoculation, spinach plants exhibited reduction in biomass accumulation, antioxidative enzymes and nutrient retention. However, plants inoculated with Bacillus sp. SDA-4 revealed significantly augmented growth, biomass accumulation and efficiency of antioxidative machinery with concomitant reduction in proline and MDA contents under Cd stress. Furthermore, application of Bacillus sp. SDA-4 assisted the Cd-stressed plants to sustain optimal levels of essential nutrients (N, P, K, Ca and Mg). It was inferred that the characterized Cd-tolerant PGPR strain, Bacillus sp. SDA-4 has a potential to reduce Cd uptake and lipid peroxidation which in turn maintained the optimum balance of nutrients and augmented the growth of Cd-stressed spinach. Analysis of bioconcentration factor (BCF) and translocation factor (TF) revealed that Bacillus sp. SDA-4 inoculation with spinach sequestered Cd in rhizospheric zone. Research outcomes are important for understanding morpho-physio-biochemical attributes of spinach-Bacillus sp. SDA-4 synergy which might provide efficient strategies to decrease Cd retention in edible plants and/or bioremediation of Cd polluted soil colloids.

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