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1.
Heliyon ; 10(1): e23030, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38169743

RESUMEN

Sclerotinia sclerotiorum, is a highly destructive pathogen with widespread impact on common bean (Phasaeolus vulgaris L.) worldwide. In this work, we investigated the efficacy of microbial consortia in bolstering host defense against sclerotinia rot. Specifically, we evaluated the performance of a microbial consortia comprising of Trichoderma erinaceum (T51) and Trichoderma viride (T52) (referred to as the T4 treatment) in terms of biochemical parameters, alleviation of the ROS induced cellular toxicity, membrane integrity (measured as MDA content), nutrient profiling, and the host defense-related antioxidative enzyme activities. Our findings demonstrate a notable enhancement in thiamine content, exhibiting 1.887 and 1.513-fold higher in the T4 compared to the un-inoculated control and the T1 treatment (only S. sclerotiorum treated). Similarly, the total proline content exhibited 3.46 and 1.24-fold higher and the total phenol content was 4.083 and 2.625-fold higher in the T4 compared to the un-inoculated control and the T1 treatment, respectively. Likewise, a general trend was found for other antioxidative and non-oxidative enzyme activities. However, results found were approximately similar in T2 treatment (bioprimed with T51) or T3 treatments (bioprimed with T52). Further, host defense attribute (survival rate) under the pathogen challenged condition was maximum in the T4 (15.55 % disease incidence) compared to others. Therefore, bio priming with consortia could be useful in reducing the economic losses incited by S. sclerotiorum in common beans.

2.
BMC Microbiol ; 23(1): 54, 2023 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-36864373

RESUMEN

BACKGROUND: Trichoderma asperellum and T. harzianum were assessed in this study as a potential biological control against Colletotrichum truncatum. C. truncatum is a hemibiotrophic fungus that causes anthracnose disease in chilli thereby affecting plant growth and fruit yield. Scanning electron microscope (SEM) technique showed the beneficial interaction between chilli root-Trichoderma spp. inducing the plant growth promotion, mechanical barrier, and defense network under C. truncatum challenged conditions. METHODS: Seeds bio-primed with T. asperellum, T. harzianum, and T. asperellum + T. harzianum promoted the plant growth parameters and strengthening of physical barrier via lignification on the wall of vascular tissues. Seed primed with bioagents were used for exploring the molecular mechanism of defense response in pepper against anthracnose to assess the temporal expression of six defense genes in the Surajmukhi variety of Capsicum annuum. QRT-PCR demonstrated induction of defense responsive genes in chilli pepper bioprimed with Trichoderma spp. such as plant defensin 1.2 (CaPDF1.2), superoxide dismutase (SOD), ascorbate peroxidase (APx), guaiacol peroxidase (GPx), pathogenesis related proteins PR-2 and PR-5. RESULTS: The results showed that bioprimed seeds were assessed for T. asperellum, T. harzianum, and T. asperellum + T. harzianum-chilli root colonization interaction under in vivo conditions. The results of the scanning electron microscope revealed that T. asperellum, T. harzianum and T. asperellum + T. harzianum interact with chilli roots directly via the development of plant-Trichoderma interaction system. Seeds bio-primed with bioagents promoted the plant growth parameters, fresh and dry weight of shoot and root, plant height, leaf area index, number of leaves, stem diameter and strengthening of physical barrier via lignification on the wall of vascular tissues and expression of six defense related genes in pepper against anthracnose. CONCLUSIONS: Application of T. asperellum and T. harzianum and in combination of treatments enhanced the plant growth. Further, as seeds bioprimed with T. asperellum, T. harzianum and in combination with treatment of T. asperellum + T. harzianum induced the strengthening of the cell wall by lignification and expression of six defense related genes CaPDF1.2, SOD, APx, GPx, PR-2 and PR-5 in pepper against C. truncatum. Our study contributed for better disease management through biopriming with T. asperellum, T. harzianum and T. asperellum + T. harzianum. The biopriming possess enormous potential to promote plant growth, modulate the physical barrier, and induced the defense related genes in chilli pepper against anthracnose.


Asunto(s)
Capsicum , Colletotrichum , Hypocreales , Colletotrichum/genética , Alcanfor
3.
J Basic Microbiol ; 61(10): 910-922, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34398489

RESUMEN

White mold and stem rot is a common disease of Phaseolus vulgaris caused by Sclerotinia sclerotiorum. Biological control is a promising alternative for the control of this disease. In the present study, two Trichoderma spp., T. erinaceum and T. viride, and the consortium of both were evaluated as biocontrol agents against sclerotinia stem rot disease. The results revealed that T. erinaceum (NAIMCC-F-02171) and T. viride (NAIMCC-F-02500) when applied alone, significantly suppressed the infection rate of S. sclerotiorum and increased the rate of survival of plants by 74.5%. On the contrary, the combination of both the Trichoderma spp. was found to be more effective in reducing stem rot by 57.2% and increasing the survival of plants by 87.5% when compared to the individual Trichoderma applications. Further, the exogenous supplementation of Trichoderma activated antioxidative machineries, such as peroxidase, polyphenol oxidase, superoxide dismutase, catalase, and ascorbic acid in the plant. Besides, hydrogen peroxide and superoxide-free radical accumulation were also found to be reduced when T. erinaceum and T. viride were used either individually or in combination under the pathogen-challenged condition. Additionally, the photopigments in the bioprimed plants were markedly increased. Moreover, the combined inoculation of the two isolates yielded the highest records of growth parameters (root weight, shoot length, and leaf weight) compared with individual inoculation. Therefore, based on the above results, it was concluded that the combination of T. erinaceum and T. viride can be effectively used as an alternative to control white mold and stem rot caused by S. sclerotiorum.


Asunto(s)
Hypocreales/patogenicidad , Phaseolus/microbiología , Enfermedades de las Plantas/microbiología , Antioxidantes , Ascomicetos , Resistencia a la Enfermedad , Peróxido de Hidrógeno/metabolismo , Pigmentos Biológicos , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Hojas de la Planta , Proteínas de Plantas/inmunología , Especies Reactivas de Oxígeno , Superóxido Dismutasa/metabolismo , Trichoderma
4.
J Fungi (Basel) ; 7(4)2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33923782

RESUMEN

In the present study, Paenibacillus dendritiformis, Trichoderma harzianum, and Trichoderma asperellum were appraised as potential biocontrol agents that induce resistance in chilli (Capsicum annuum) against the devastating pathogen Colletotrichum truncatum, which causes anthracnose. Bright-field and scanning electron micrographs showed the hyphal degradation, lysis, and abnormal swelling in C. truncatum against P. dendritiformis in a dual plate assay. Under greenhouse conditions, chilli seeds pretreated with P. dendritiformis, T. asperellum, T. harzianum, and T. asperellum + T. harzianum by soil soak method inflicted an induced systemic resistance (ISR) in chilli against a C. truncatum-challenged condition. In chilli, the disease index percentage was significantly reduced in the T. asperellum + T. harzianum-treated seeds, followed by the T. harzianum-, T. asperellum-, and P. dendritiformis-treated seeds as compared to the untreated and challenged, respectively. Chilli seeds were primed with T. asperellum + T. harzianum (78.67%), which revealed maximum disease protection under the challenged condition, followed by T. harzianum (70%), T. asperellum (64%), and P. dendritiformis (56%) as compared to untreated and C. truncatum-challenged (6%) condition served as control. The seeds that were pretreated with biocontrol agents (BCAs) inflicted ISR against C. truncatum by enhancing the activity of defence-related enzymes (superoxide dismutase (SOD), peroxidase (POX), polyphenol oxidase (PPO), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and phenylalanine ammonia-lyase (PAL)), accumulating phenolic compounds, and increasing the relative chlorophyll content in chilli. Nitroblue tetrazolium (NBT) and 3,3'-Diaminobenzidine (DAB) stains were used to detect the accumulation of superoxide anion and hydrogen peroxide that appeared nearby the fungal infection sites. The accumulation of reactive oxygen species (O2- and H2O2) in the pathogen-inoculated leaves was a maximum of 48 hpi, followed by P. dendritiformis, T. asperellum, T. harzianum, and T. asperellum + T. harzianum treated tissue upon C. truncatum-challenged condition as compared to the control. Overall, our results showed the potential of T. harzianum, T. asperellum, and P. dendritiformis as biocontrol agents that prevent infection by C. truncatum and inflict an induced systemic resistance in chilli by enhancing the biosynthesis of phenolic compounds, defence and antioxidative enzymes, and reducing the lesion development and reactive oxygen species accumulation. This is the first report of induced systemic resistance against anthracnose in chilli obtained by application of T. harzianum, T. asperellum and P. dendritiformis, through seed priming.

5.
J Basic Microbiol ; 60(10): 828-861, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32815221

RESUMEN

Plant growth-promoting rhizobacteria (PGPR) are diverse groups of plant-associated microorganisms, which can reduce the severity or incidence of disease during antagonism among bacteria and soil-borne pathogens, as well as by influencing a systemic resistance to elicit defense response in host plants. An amalgamation of various strains of PGPR has improved the efficacy by enhancing the systemic resistance opposed to various pathogens affecting the crop. Many PGPR used with seed treatment causes structural improvement of the cell wall and physiological/biochemical changes leading to the synthesis of proteins, peptides, and chemicals occupied in plant defense mechanisms. The major determinants of PGPR-mediated induced systemic resistance (ISR) are lipopolysaccharides, lipopeptides, siderophores, pyocyanin, antibiotics 2,4-diacetylphoroglucinol, the volatile 2,3-butanediol, N-alkylated benzylamine, and iron-regulated compounds. Many PGPR inoculants have been commercialized and these inoculants consequently aid in the improvement of crop growth yield and provide effective reinforcement to the crop from disease, whereas other inoculants are used as biofertilizers for native as well as crops growing at diverse extreme habitat and exhibit multifunctional plant growth-promoting attributes. A number of applications of PGPR formulation are needed to maintain the resistance levels in crop plants. Several microarray-based studies have been done to identify the genes, which are associated with PGPR-induced systemic resistance. Identification of these genes associated with ISR-mediating disease suppression and biochemical changes in the crop plant is one of the essential steps in understanding the disease resistance mechanisms in crops. Therefore, in this review, we discuss the PGPR-mediated innovative methods, focusing on the mode of action of compounds authorized that may be significant in the development contributing to enhance plant growth, disease resistance, and serve as an efficient bioinoculants for sustainable agriculture. The review also highlights current research progress in this field with a special emphasis on challenges, limitations, and their environmental and economic advantages.


Asunto(s)
Fenómenos Fisiológicos Bacterianos , Resistencia a la Enfermedad , Fenómenos Fisiológicos de las Plantas , Plantas/microbiología , Inoculantes Agrícolas , Bacterias/clasificación , Bacterias/metabolismo , Productos Agrícolas/crecimiento & desarrollo , Productos Agrícolas/inmunología , Productos Agrícolas/metabolismo , Productos Agrícolas/microbiología , Resistencia a la Enfermedad/genética , Desarrollo de la Planta , Plantas/inmunología , Plantas/metabolismo , Suelo/química , Microbiología del Suelo
6.
Front Pharmacol ; 9: 1038, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30405403

RESUMEN

Vascular wilt of tomato caused by Fusarium oxysporum f.sp. lycopersici (FOL) is one of the most devastating diseases, that delimits the tomato production worldwide. Fungal short-chain dehydrogenases/reductases (SDRs) are NADP(H) dependent oxidoreductases, having shared motifs and common functional mechanism, have been demonstrated as biochemical targets for commercial fungicides. The 1,3,6,8 tetra hydroxynaphthalene reductase (T4HNR) protein, a member of SDRs family, catalyzes the naphthol reduction reaction in fungal melanin biosynthesis. We retrieved an orthologous member of T4HNR, (complexed with NADP(H) and pyroquilon from Magnaporthe grisea) in the FOL (namely; FOXG_04696) based on homology search, percent identity and sequence similarity (93% query cover; 49% identity). The hypothetical protein FOXG_04696 (T4HNR like) had conserved T-G-X-X-X-G-X-G motif (cofactor binding site) at N-terminus, similar to M. grisea (1JA9) and Y-X-X-X-K motif, as a part of the active site, bearing homologies with two fungal keto reductases T4HNR (M. grisea) and 17-ß-hydroxysteroid dehydrogenase from Curvularia lunata (teleomorph: Cochliobolus lunatus PDB ID: 3IS3). The catalytic tetrad of T4HNR was replaced with ASN115, SER141, TYR154, and LYS158 in the FOXG_04696. The structural alignment and superposition of FOXG_04696 over the template proteins (3IS3 and 1JA9) revealed minimum RMSD deviations of the C alpha atomic coordinates, and therefore, had structural conservation. The best protein model (FOXG_04696) was docked with 37 fungicides, to evaluate their binding affinities. The Glide XP and YASARA docked complexes showed discrepancies in results, for scoring and ranking the binding affinities of fungicides. The docked complexes were further refined and rescored from their docked poses through 50 ns long MD simulations, and binding free energies (ΔGbind) calculations, using MM/GBSA analysis, revealed Oxathiapiprolin and Famoxadone as better fungicides among the selected one. However, Famoxadone had better interaction of the docked residues, with best protein ligand contacts, minimum RMSD (high accuracy of the docking pose) and RMSF (structural integrity and conformational flexibility of docking) at the specified docking site. The Famoxadone was found to be acceptable based on in silico toxicity and in vitro growth inhibition assessment. We conclude that the FOXG_04696, could be employed as a novel candidate protein, for structure-based design, and screening of target fungicides against the FOL pathogen.

7.
PLoS One ; 13(4): e0193922, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29709017

RESUMEN

The WRKY transcription factors have indispensable role in plant growth, development and defense responses. The differential expression of WRKY genes following the stress conditions has been well demonstrated. We investigated the temporal and tissue-specific (root and leaf tissues) differential expression of plant defense-related WRKY genes, following the infection of Fusarium oxysporum f. sp. lycopersici (Fol) in tomato. The genome-wide computational analysis revealed that during the Fol infection in tomato, 16 different members of WRKY gene superfamily were found to be involved, of which only three WRKYs (SolyWRKY4, SolyWRKY33, and SolyWRKY37) were shown to have clear-cut differential gene expression. The quantitative real time PCR (qRT-PCR) studies revealed different gene expression profile changes in tomato root and leaf tissues. In root tissues, infected with Fol, an increased expression for SolyWRKY33 (2.76 fold) followed by SolyWRKY37 (1.93 fold) gene was found at 24 hrs which further increased at 48 hrs (5.0 fold). In contrast, the leaf tissues, the expression was more pronounced at an earlier stage of infection (24 hrs). However, in both cases, we found repression of SolyWRKY4 gene, which further decreased at an increased time interval. The biochemical defense programming against Fol pathogenesis was characterized by the highest accumulation of H2O2 (at 48 hrs) and enhanced lignification. The functional diversity across the characterized WRKYs was explored through motif scanning using MEME suite, and the WRKYs specific gene regulation was assessed through the DNA protein docking studies The functional WRKY domain modeled had ß sheets like topology with coil and turns. The DNA-protein interaction results revealed the importance of core residues (Tyr, Arg, and Lys) in a feasible WRKY-W-box DNA interaction. The protein interaction network analysis revealed that the SolyWRKY33 could interact with other proteins, such as mitogen-activated protein kinase 5 (MAPK), sigma factor binding protein1 (SIB1) and with other WRKY members including WRKY70, WRKY1, and WRKY40, to respond various biotic and abiotic stresses. The STRING results were further validated through Predicted Tomato Interactome Resource (PTIR) database. The CELLO2GO web server revealed the functional gene ontology annotation and protein subcellular localization, which predicted that SolyWRKY33 is involved in amelioration of biological stress (39.3%) and other metabolic processes (39.3%). The protein (SolyWRKY33) most probably located inside the nucleus (91.3%) with having transcription factor binding activity. We conclude that the defense response following the Fol challenge was accompanied by differential expression of the SolyWRKY4(↓), SolyWRKY33(↑) and SolyWRKY37(↑) transcripts. The biochemical changes are occupied by elicitation of H2O2 generation and accumulation and enhanced lignified tissues.


Asunto(s)
Resistencia a la Enfermedad/genética , Fusarium , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/genética , Solanum lycopersicum/genética , Factores de Transcripción/genética , Solanum lycopersicum/metabolismo , Solanum lycopersicum/microbiología , Proteínas de Plantas/metabolismo , Factores de Transcripción/metabolismo
8.
Plant Physiol Biochem ; 118: 320-332, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28683401

RESUMEN

Fusarium wilt is one of the most prevalent and damaging diseases of tomato. Among various toxins secreted by the Fusarium oxysporum f. sp. lycopersici (causal agent of Fusarium wilt of tomato), fusaric acid (FA) is suspected to be a potent pathogenicity factor in tomato wilt disease development. With this rationale the present study was carried out with physiological, biochemical and proteomic perspectives. Treatment of FA was given to the leaves of tomato directly through infiltration to show the characteristic features of Fusarium wilt of tomato. The phytotoxic effect of FA was assessed in the form of cell death in tomato leaves which was observed by increased uptake of Evans blue stain. The measurement of electrolyte leakage was used as an indicator of the extent of cell death. The influence of FA on the leaf photosynthesis of tomato plant was investigated and it was found that FA strongly reduced the photosynthetic pigment contents of tomato leaves resulting to heavy suppression of leaf photosynthesis processes, which therefore affected leaf physiology finally leading to leaf wilting and necrosis. This cell death inducer (FA) produced an enormous oxidative burst during which large quantities of reactive oxygen species (ROS) like H2O2 was generated in the treated leaf tissues of tomato plants which was evident from enhancement in lipid peroxidation. To assess the involvement of proteolysis in the cell death cascade induced by FA treatment, total protease activity was measured in the leaf tissues and it was found that the total protease activity increased with the treatment and leading to cell death. Furthermore, proteomic study was used as a powerful tool to understand the alterations in cellular protein expression in response to FA exposure. Differential expression in several proteins was observed in the present study. Proteomic analyses, thus, clearly indicate that proteins belonging to different functional classes are significantly affected in the plant leaf tissues after FA exposure leading to deterioration of structure and metabolism of cells. Thus, it is concluded that FA plays an important role in fungal pathogenicity by decreasing cell viability.


Asunto(s)
Ácido Fusárico/toxicidad , Enfermedades de las Plantas , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Solanum lycopersicum/metabolismo , Ácido Fusárico/química , Fusarium/química , Peroxidación de Lípido/efectos de los fármacos , Fotosíntesis/efectos de los fármacos , Proteolisis/efectos de los fármacos , Proteómica
9.
Microbiol Res ; 193: 74-86, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27825488

RESUMEN

In the present study we bioprimed seeds of six vegetable crops (tomato, brinjal, chilli, okra, ridge gourd and guar) with different spore doses of Trichoderma asperellum BHUT8 ranging from 102 to 108 spores ml-1 and the effect of biopriming was seen on seed germination and development. The most effective spore dose for enhancement in seed germination and radicle length was found to be 103 spores ml-1 in tomato and ridge gourd, 104 spores ml-1 in brinjal and okra while 106 spores ml-1 in chilli and guar. At the most effective spore dose, the increase in germination percentage was 5, 146.15, 112.5, 5.4, 28.13 and 0% while increase in radicle length was 73.17, 50.83, 171.6, 107.35, 247.19 and 90.79% in tomato, brinjal, chilli, okra, ridge gourd and guar, respectively, compared to their controls. Higher spore dose i.e. 107-108 spores ml-1 and 106-108 spores ml-1 in tomato and brinjal, respectively, reduced seed germination percentage and radicle growth compared to their controls. Biopriming with T. asperellum BHUT8 also triggered various defense like responses such as high phenylpropanoid activities and lignifications in bioprimed tomato seedlings compared to the non-bioprimed tomato seedlings demonstrating possible use of BHUT8 against phytopathogens.


Asunto(s)
Esporas Fúngicas/crecimiento & desarrollo , Trichoderma/crecimiento & desarrollo , Verduras/crecimiento & desarrollo , Verduras/microbiología , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Semillas/crecimiento & desarrollo , Semillas/microbiología
10.
Nat Biotechnol ; 34(10): 1046-1051, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27598229

RESUMEN

Whitefly (Bemisia tabaci) damages field crops by sucking sap and transmitting viral diseases. None of the insecticidal proteins used in genetically modified (GM) crop plants to date are effective against whitefly. We report the identification of a protein (Tma12) from an edible fern, Tectaria macrodonta (Fee) C. Chr., that is insecticidal to whitefly (median lethal concentration = 1.49 µg/ml in in vitro feeding assays) and interferes with its life cycle at sublethal doses. Transgenic cotton lines that express Tma12 at ∼0.01% of total soluble leaf protein were resistant to whitefly infestation in contained field trials, with no detectable yield penalty. The transgenic cotton lines were also protected from whitefly-borne cotton leaf curl viral disease. Rats fed Tma12 showed no detectable histological or biochemical changes, and this, together with the predicted absence of allergenic domains in Tma12, indicates that Tma12 might be well suited for deployment in GM crops to control whitefly and the viruses it carries.


Asunto(s)
Helechos/metabolismo , Gossypium/genética , Gossypium/parasitología , Hemípteros/virología , Insecticidas/metabolismo , Proteínas de Plantas/metabolismo , Animales , Helechos/genética , Mejoramiento Genético/métodos , Gossypium/virología , Hemípteros/patogenicidad , Proteínas de Plantas/genética , Ingeniería de Proteínas/métodos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
11.
Braz. j. microbiol ; 47(1): 10-17, Jan.-Mar. 2016. graf
Artículo en Inglés | LILACS | ID: lil-775109

RESUMEN

Abstract The antagonistic potential of Trichoderma strains was assayed by studying the effect of their culture filtrate on the radial growth of Sclerotium rolfsii, the causal agent of chickpea collar rot. Trichoderma harzianum-1432 (42.2%) and Trichoderma atroviride (40.3%) were found to be strong antagonists. To enhance their antagonistic potential, mutagenesis of these two selected strains was performed. Two mutants, Th-m1 and T. atroviride m1, were found to be more effective than their parent strains. The enzymatic activities of the selected parent and mutant strains were assayed, and although both mutants were found to have enhanced enzymatic activities compared to their respective parent strains, Th-m1 possessed the maximum cellulase (5.69 U/mL) and β-1,3-glucanase activity (61.9 U/mL). Th-m1 also showed high competitive saprophytic ability (CSA) among all of the selected parent and mutant strains, and during field experiments, Th-m1 was found to successfully possess enhanced disease control (82.9%).


Asunto(s)
Antibiosis/efectos de los fármacos , Basidiomycota/crecimiento & desarrollo , Mutagénesis , Mutágenos/metabolismo , Enfermedades de las Plantas/prevención & control , Trichoderma/efectos de los fármacos , Trichoderma/fisiología , Cicer/microbiología , Hidrolasas/análisis , Mutación , Enfermedades de las Plantas/microbiología , Trichoderma/enzimología , Trichoderma/crecimiento & desarrollo
12.
Braz J Microbiol ; 47(1): 10-7, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26887221

RESUMEN

The antagonistic potential of Trichoderma strains was assayed by studying the effect of their culture filtrate on the radial growth of Sclerotium rolfsii, the causal agent of chickpea collar rot. Trichoderma harzianum-1432 (42.2%) and Trichoderma atroviride (40.3%) were found to be strong antagonists. To enhance their antagonistic potential, mutagenesis of these two selected strains was performed. Two mutants, Th-m1 and T. atroviride m1, were found to be more effective than their parent strains. The enzymatic activities of the selected parent and mutant strains were assayed, and although both mutants were found to have enhanced enzymatic activities compared to their respective parent strains, Th-m1 possessed the maximum cellulase (5.69U/mL) and ß-1,3-glucanase activity (61.9U/mL). Th-m1 also showed high competitive saprophytic ability (CSA) among all of the selected parent and mutant strains, and during field experiments, Th-m1 was found to successfully possess enhanced disease control (82.9%).


Asunto(s)
Antibiosis/efectos de los fármacos , Basidiomycota/crecimiento & desarrollo , Mutagénesis , Mutágenos/metabolismo , Enfermedades de las Plantas/prevención & control , Trichoderma/efectos de los fármacos , Trichoderma/fisiología , Cicer/microbiología , Hidrolasas/análisis , Mutación , Enfermedades de las Plantas/microbiología , Trichoderma/enzimología , Trichoderma/crecimiento & desarrollo
13.
Bot Stud ; 55(1): 66, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28510945

RESUMEN

BACKGROUND: Fusaric acid (FA) has been shown to stimulate the rapid development of disease symptoms, such as necrosis and foliar desiccation. In this study, we have evaluated the phytotoxicity of FA on tomato plants (Solanum lycopersicum L.). FA induced necrotic lesions in detached leaves, which are reminiscent of hypersensitive response (HR) lesions induced by plant-pathogen interactions and other abiotic stress factors. RESULTS: FA-treated tomato leaves exhibited visible necrotic lesion as a result of cell death which was evident by Evans blue staining, enhanced reactive oxygen species (ROS) levels and DNA degradation. Changes in the generation of O2.- and H2O2 as well as the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were examined in FA-treated tomato leaves. It was observed that FA exposure stimulated oxidative burst in the leaves, resulting in a lasting activation of O2.- and H2O2 production. After first day of FA application, the H2O2 scavenging enzymes CAT and APX showed a strong activity decrease followed by gradual recovery to the control level after 2 and 3 days. CONCLUSION: A concomitant increase in ROS production, the down regulation of antioxidative enzymes activities and upregulation of lipid peroxidation were crucial for the onset of cell death. These results suggested that FA-induced damage might result from ROS pathways. Thus, our experiments provide a useful model plant system for research on FA-induced plant cell death.

14.
Appl Microbiol Biotechnol ; 97(13): 5659-68, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23720032

RESUMEN

The field of allelopathy is one of the most fascinating but controversial processes in plant ecology that offers an exciting, interdisciplinary, complex, and challenging study. In spite of the established role of soil microbes in plant health, their role has also been consolidated in studies of allelopathy. Moreover, allelopathy can be better understood by incorporating soil microbial ecology that determines the relevance of allelopathy phenomenon. Therefore, while discussing the role of allelochemicals in plant-plant interactions, the dynamic nature of soil microbes should not be overlooked. The occurrence and toxicity of allelochemicals in soil depend on various factors, but the type of microflora in the surroundings plays a crucial role because it can interfere with its allelopathic nature. Such microbes could be of prime importance for biological control management of weeds reducing the cost and ill effects of chemical herbicides. Among microbes, our main focus is on bacteria--as they are dominant among other microbes and are being used for enhancing crop production for decades--and fungi. Hence, to refer to both bacteria and fungi, we have used the term microbes. This review discusses the beneficial role of microbes in reducing the allelopathic effects of weeds. The review is mainly focused on various functions of bacteria in (1) reducing allelopathic inhibition caused by weeds to reduce crop yield loss, (2) building inherent defense capacity in plants against allelopathic weed, and (3) deciphering beneficial rhizospheric process such as chemotaxis/biofilm, degradation of toxic allelochemicals, and induced gene expression.


Asunto(s)
Alelopatía , Bacterias/metabolismo , Hongos/metabolismo , Feromonas/metabolismo , Malezas/fisiología , Microbiología del Suelo , Bacterias/crecimiento & desarrollo , Biotransformación , Hongos/crecimiento & desarrollo , Malezas/crecimiento & desarrollo , Malezas/metabolismo
15.
Microbiol Res ; 168(1): 33-40, 2013 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-22857806

RESUMEN

The study was conducted to examine efficacy of a rhizospheric microbial consortium comprising of a fluorescent Pseudomonas (PHU094), Trichoderma (THU0816) and Rhizobium (RL091) strain on activation of physiological defense responses in chickpea against biotic stress caused by the collar rot pathogen Sclerotium rolfsii. Results of individual microbes were compared with dual and triple strain mixture treatments with reduced microbial load (1/2 and 1/3rd, respectively, of individual microbial load compared to single microbe application) in the mixtures. Periodical studies revealed maximum activities of phenylalanine ammonia lyase [E.C. 4.1.3.5] and polyphenol oxidase [E.C. 1.14.18.1] and accumulation of total phenol content in chickpea in the triple microbe consortium treated plants challenged with the pathogen compared to the single microbe and dual microbial consortia. Similarly, the expression of the antioxidant enzymes superoxide dismutase [E.C.1.15.1.1] and peroxidase [E.C.1.11.1.7] was also highest in the triple microbial consortium which was correlated with lesser lipid peroxidation in chickpea under the biotic stress. Histochemical staining clearly showed maximum and uniform lignification in vascular bundles of chickpea stem sections treated with the triple microbes. The physiological responses were directly correlated with the mortality rate as least plant mortality was recorded in the triple microbe consortium treated plants. The results thus suggest an augmented elicitation of stress response in chickpea under S. rolfsii stress by the triple microbial consortium in a synergistic manner under reduced microbial load.


Asunto(s)
Antioxidantes/metabolismo , Basidiomycota/patogenicidad , Cicer/microbiología , Fenoles/metabolismo , Raíces de Plantas/microbiología , Microbiología del Suelo , Estrés Fisiológico , Catecol Oxidasa/metabolismo , Cicer/fisiología , Datos de Secuencia Molecular , Peroxidasa/metabolismo , Fenilanina Amoníaco-Liasa/metabolismo , Pseudomonas/aislamiento & purificación , Pseudomonas/metabolismo , Rhizobium/aislamiento & purificación , Rhizobium/metabolismo , Rizosfera , Análisis de Secuencia de ADN , Superóxido Dismutasa/metabolismo , Trichoderma/metabolismo
16.
Pediatr Nephrol ; 23(11): 2047-51, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18553110

RESUMEN

The production of free radicals can cause renal injury and play a role in the pathogenesis of acute renal failure (ARF). The indirect markers of reactive oxygen species (ROS) were evaluated in children with ARF and controls. Forty patients with ARF aged 0-10 years were selected. Twenty age- and gender-matched healthy children were included as controls. Plasma malondialdehyde, protein carbonyl, nitrite, copper, ascorbic acid, zinc, and ceruloplasmin levels were estimated in patients with ARF and controls. The plasma malondialdehyde (p < 0.01), copper (p < 0.001), ascorbic acid (p < 0.05), and ceruloplasmin (p < 0.001) levels were significantly raised in ARF patients in comparison with controls. Significantly higher levels of plasma malondialdehyde (p < 0.01), nitrite (p < 0.001), copper (p < 0.001), and ceruloplasmin (p < 0.001) and lower plasma zinc (p < 0.01) were found in ARF nonsurvivors in comparison with survivors. The cutoff levels of plasma nitrite and ceruloplasmin were found to be most accurate in predicting mortality in ARF patients and had maximum sensitivity (100%) and specificity (60.7%) among the parameters studied. In conclusion, the increased levels of oxidants and antioxidants suggest the production of ROS and their possible role in ARF pathogenesis. Plasma nitrite and ceruloplasmin concentrations demonstrated predictive ability in relation to mortality.


Asunto(s)
Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/mortalidad , Antioxidantes/metabolismo , Biomarcadores/sangre , Especies Reactivas de Oxígeno/metabolismo , Ácido Ascórbico/sangre , Ceruloplasmina/metabolismo , Niño , Preescolar , Cobre/sangre , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Malondialdehído/sangre , Nitritos/sangre , Valor Predictivo de las Pruebas , Carbonilación Proteica , Zinc/sangre
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