ABSTRACT
O objetivo deste trabalho foi verificar as atividades antibacteriana e indutora de resistência de extratos de Pycnoporus sanguineus para controle do crestamento bacteriano comum, causado por Xanthomonas axonopodis pv. phaseoli, em feijoeiro. In vitro foram utilizados extratos aquosos de basidiocarpo, micélio e filtrado de cultura de P. sanguineus nas concentrações de 1, 5, 10, 15 e 20%, além das testemunhas água, acibenzolar-S-metil (ASM - 125 mg i.a. L-1) e antibiótico (22,5 mg L-1 de oxitetraciclina + 225 mg L-1 de estreptomicina). In vivo foram realizadas avaliações de severidade e atividade de peroxidase, polifenoloxidase, ß-1,3 glucanase e fenilalanina amônia-liase, com o uso de extrato aquoso de micélio e de basidiocarpo e filtrado de cultura de P. sanguineus a 5% e 10%. Verificou-se atividade antibacteriana apenas para o filtrado de cultura em concentrações acima de 15% e para o extrato de basidiocarpo nas concentrações de 1 a 20%. In vivo, os resultados indicaram o potencial de extratos de basidiocarpos de P. sanguineus para o controle de X. axonopodis pv. phaseoli em feijoeiro, com redução média de 56% na severidade, o que pode ter ocorrido tanto por atividade antimicrobiana direta quanto por indução de resistência, envolvendo principalmente a ativação das enzimas de defesa vegetal peroxidase e polifenoloxidase.
The aim of this work was to verify the antimicrobial and resistance induction activities of Pycnoporus sanguineus extracts for the control of common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli. In vitro assays were performed using aqueous extracts from basidiocarp, mycelium and culture filtrate of P. sanguineus in concentrations of 1, 5, 10, 15 and 20%, with water, acibenzolar-S-methyl (ASM - 125 mg a.i. L-1) and antibiotic (oxytetracycline 22.5 mg L-1 + streptomycin 225 mg L-1) as control treatments. For the in vivo assays the disease severity and the activities of peroxidase, polyphenol oxidase, ß-1,3 glucanase and phenylalanine ammonia-lyase were evaluated using extracts of mycelium, basidiocarp and culture filtrate of P. sanguineus at 5% and 10%. Antibacterial activity was verified only for culture filtrate in concentrations above 15% and for concentrations of 1% to 20% of basidiocarp extract. The results of the in vivo assays indicated the potential of basidiocarps extracts from P. sanguineus for the control of X. axonopodis pv. phaseoli in beans, with an average severity reduction of 56%, which may have been due either to direct antimicrobial activity or to resistance induction involving mainly the activation of the plant defense enzymes peroxidase and polyphenol oxidase.
Subject(s)
Xanthomonas axonopodis/pathogenicity , Pycnoporus , Fabaceae/chemistry , Anti-Bacterial Agents/analysisABSTRACT
En este trabajo se analizó el líquido de lavado intercelular de Lycopersicon escu-lentum ceraciforme L1568 perteneciente al germoplasma nacional con resistencia en campo a P. infestans el cual mostró la presencia de cuatro ß (1,3) glucanasas después de infección con el patógeno. Para tal efecto las plantas se inocularon con el patógeno con el fin de inducir aumento en la concentración de las proteínas PR y otras sustancias relacionadas con defensa; 15 días después de la inoculación con el parásito, se extrajo el líquido de lavado intercelular de las hojas de tomate utilizando agua. Las proteínas con actividad de ß (1,3) glucanasa extraídas se liofilizaron, se resuspendieron en búfer, se purificaron utilizando cromatografía de exclusión, intercambio iónico y electroforesis preparativa. Los resultados de caracterización parcial, mostraronlaexistenciadeuna ß (1,3) glucanasa básica con peso molecular de 36,8 kDa y pI 9,2 y tres ß (1,3) glucanasas ácidas de 35,4; 30,1 y 7,2 kDa con puntos isoeléctricos de 3,8; 3,6 y 5,0 respectivamente. Adicionalmente se determinaron las propiedades cinéticas de cada enzima, KM, Vmáx,Eo yK3 encontrando, de acuerdo con los resultados obtenidos, que la proteína básica no ha sido reportada en la literatura relacionada con tomate.
In this paper was analysed the intercellular washing fluid of Lycopersicon esculentum ceraciforme L1568 belonging to the national germplasm with resistance to P. infestans in field which showed the presence of four ß (1,3) glucanases after infection with the pathogen. For this purpose the plants were inoculated with the pathogen to induce a concentration increase of PR proteins and other defence-related substances, 15 days after inoculation with the parasite was extracted the intercellular washing fluid of tomato leaves using water. The proteins with ß(1,3) glucanase activity were extracted, freeze-dried and re-suspended in buffer solution and were purified using exclusion chromatography, ion exchange chromatography and preparative electrophoresis. The results of partial characterization showed the presence of a basic ß (1,3) glucanase with a molecular weight of 36.8 kDa and pi 9.2 and three ß (1,3) glu-canase acid 35.4, 30.1 and 7.2 kDa with isoelectric points of 3.8, 3.6 and 5.0 respectively. Additionally it was determined the kinetic properties of each enzyme, KM,Vmax, and Eo,K3, according to the results, the basic protein has not been reported in the literature related to tomato.
Este trabalho analisou o líquido de lavado intercelular de Lycopersicon esculentum ceraciforme L1568 pertencente ao ger-moplasma nacional com resistência em campo a P. infestans, mostrau a presença de quatro ß (1,3) glucanase despois a infecção com o agente patogênico. Para este efeito as plantas foram inoculadas com o agente patogénico para induzir um aumento na concentração das proteínas PR y outras substâncias relacionadas com defesa, e 15 dias mais tarde se extraiu o líquido de lavado intercelular de folhas de tomate utilizando água. As proteínas extraídas foram liofilizadas, resuspendidas em solução tampão, purificadas utilizando cromatografia de exclusão, de intercambio iónico e electroforesepreparativa,. Os resultados da caracterização paracial revelou a existência de uma ß(1,3) glucanasa basica com peso molecular de 36,8 kDa e PI 9,2, e três ß(1,3) glucanasas ácidas de 35.4, 30.1 e 7.2 kDa com pontos isoeléctricos de 3.8, 3.6y 5.0, respectivamente. Adicionalmente, foi possível determinar as propriedades cinéticas KM,Vmax,Eo yK3 de cada enzima, encontrando de acordo com os resultados que a proteína básica não havia sido reportada na literatura.relacionada com tomate.
ABSTRACT
In silico expression profiles, of the discovered 3,103 citrus ESTs putatively encoding for PR protein families (PR-1 to PR-17), were evaluated using the Brazil citrus genome EST CitEST/database. Hierarchical clustering was displayed to identify similarities in expression patterns among citrus PR-like gene families (PRlgf) in 33 selected cDNA libraries. In this way, PRlgf preferentially expressed by organ and citrus species, and library conditions were highlighted. Changes in expression profiles of clusters for each of the 17 PRlgf expressed in organs infected by pathogens or drought-stressed citrus species were displayed for relative suppression or induction gene expression in relation to the counterpart control. Overall, few PRlgf showed expression 2-fold higher in pathogen-infected than in uninfected organs, even though the differential expression profiles displayed have been quite diverse among studied species and organs. Furthermore, an insight into some contigs from four PRlgf pointed out putative members of multigene families. They appear to be evolutionarily conserved within citrus species and/or organ- or stress-specifically expressed. Our results represent a starting point regarding the extent of expression pattern differences underlying PRlgf expression and reveal genes that may prove to be useful in studies regarding biotechnological approaches or citrus resistance markers.
ABSTRACT
Se aislaron y caracterizaron parcialmente proteínas antifúngicas de los espacios intercelulares de hojas de tomate Lycopersicon esculentum cerasiforme, variedad que ha mostrado resistencia en campo a Phytophthora Infestans; se observó que después de inoculación con el patógeno dichas proteínas se acumularon sistémicamente en la planta. Las proteínas identificadas mostraron características de Defensinas de plantas, una nueva familia de proteínas con bajo peso molecular, carga positiva a pH fisiológico y actividad antifúngica evaluada in vitro contra P. infestans. Los análisis electroforéticos en geles de poliacrilamida con SDS-Tricina en condiciones reductoras y no reductoras, sugirieron que están asociadas en trímeros y tetrámeros y poseen pesos moleculares de 5,2 kDa.
Antifungal Proteins from intercellular space of Tomato leaves Lycopersicon esculentum cerasiforme were isolated and partially characterized; this variety had shown resistance against Phytophthora infestans, after inoculating plants with the pathogen it was observed that these proteins were accumulated systemically. The isolated proteins be haved as plant defensins, a novel protein family, with low molecular weight, cationics at physiological pH and Antifungal Activity in vitro evaluated against P. infestans. Electrophoretic analyses in SDS Tricine-PAGE, under reducing and non-reducing conditions suggested that, they were associated as trimers and tetramers; and have molecular weights of 5,2 kDa.
ABSTRACT
Pseudomonas fluorescens 1-94 induced systemic resistance in chickpea against Fusarium wilt of chickpea caused by Fusarium oxysporum f. sp. ciceri by the synthesis and accumulation of phenolic compounds, phenylalanine ammonia lyase(PAL) and pathogenesis related(PR) proteins(chitinase, beta-1,3-glucanase and peroxidase). Time-course accumulation of these enzymes in chickpea plants inoculated with P. fluorescens was significantly(LSD, P=0.05) higher than control. Maximum activities of PR-proteins were recorded at 3 days after inoculation in all induced plants; thereafter, the activity decreased progressively. Five PR peroxidases detected in induced chickpea plants. Molecular mass of these purified peroxidases was 20, 29, 43, 66 and 97 kDa. Purified peroxidases showed antifungal activity against plant pathogenic fungi.
Subject(s)
Ammonia , Cicer , Fungi , Fusarium , Peroxidases , Phenol , Phenylalanine , Plants , Pseudomonas fluorescens , PseudomonasABSTRACT
Plants have the ability to acquire an enhanced level of resistance to pathogen attack after being exposed to specific biotic stimuli. To obtain plant growth-promoting rhizobacteria inducing resistance against cucumber anthracnose by Colletotrichum orbiculare, more than 800 strains of rhizobacteria were screened in the greenhouse. Among these strains, Bacillus amyloliquefaciens solate EXTN-1 showed significant disease control efficacy on the plants. Induction of pathogenesis-related(PR-la) gene expression by EXTN-1 was assessed using tobacco plants transformed with PR-1a::beta-glucuronidase (GUS) construct. GUS activities of tobacco treated with EXTN-1 and salicylic acid-treated transgenic tobacco were significantly higher than those of tobacco plants with other treatments. Gene expression analyses indicated that EXTN-1 induces the accumulation of defense-related genes of tobacco. The results showed that some defense genes are expressed by the treatment with EXTN-1 suggesting the similar resistance mechanism by salicylic acid.