scholarly journals Characterization of strawberry associated fungi and in vitro antagonistic effect of Trichoderma harzianum

Author(s):  
Luis Angel Morales-Mora ◽  
Petra Andrade-Hoyos ◽  
M. Angeles Valencia-de Ita ◽  
Omar Romero-Arenas ◽  
Hilda Victoria Silva-Rojas ◽  
...  

México es el tercer productor de fresa a nivel mundial, donde la producción de este cultivo es de importancia económica y generación de divisas en el pais. El objetivo de la presente investigación fue identificar y caracterizar morfológicamente los hongos asociados a enfermedades en un cultivo de la fresa, así como determinar la capacidad antagónica <em>in vitro</em> de la cepa T-H4 de <em>Trichoderma harzianum</em> con los hongos identificados. Se colectaron muestras de plantas del cultivo de fresa con síntomas de enfermedades fúngicas, se sembraron en medio PDA y se generaron cultivos monospóricos para su caracterización morfológica. Los hongos identificados y la cepa T-H4 se confrontaron mediante cultivos duales. Se identificaron tres hongos asociados al fruto (<em>A. niger</em>, <em>Colletotrichum</em> sp. y <em>R. stolonifer</em>), tres en hojas y tallo (<em>Pestalotiopsis</em> sp., <em>Curvularia</em> sp. y <em>Alternaria</em> sp.) y dos hongos asociados a la raíz (<em>Rhizoctonia</em> sp. y <em>Fusarium</em> sp.). La cepa T-H4 presentó un nivel antagónico adecuado para <em>Colletotrichum</em> sp., <em>Pestalotiopsis</em> sp., <em>Alternaria</em> sp., <em>Rhizoctonia</em> sp. y <em>Curvularia</em> sp.,<em> in vitro.</em> Se sugiere realizar evaluaciones de control biológico con estos aislamientos en invernadero y a campo abierto, así como determinar su patogenicidad.

2018 ◽  
Vol 8 (1) ◽  
pp. 88-91 ◽  
Author(s):  
M. Skaptsov ◽  
S. Smirnov ◽  
M. Kutsev ◽  
O. Uvarova ◽  
T. Sinitsyna ◽  
...  

<p><em>Trichoderma</em> isolates (SSBGT07, SSBGT08, SSBGT09, SSBGT10) were isolated from the soil samples of the South-Siberian Botanical Garden and identified using morphological observation and ITS region analysis as <em>Trichoderma harzianum</em>, <em>T. asperellum, T. ghanense</em>, and <em>T. longibranchiatum</em>. Antagonistic activity against <em>Cladosporium </em>sp. and<em> Botrytis </em>sp. was evaluated <em>in vitro</em>. All isolates showed antagonistic effect by competition against <em>Cladosporium </em>sp. <em>T. asperellum </em>and <em>T. longibranchiatum</em> showed antagonism against <em>Botrytis </em>sp. All isolates showed hyper sporulation on the sclerotia of <em>Botrytis</em> sp. (except the <em>T. ghanense</em>) and colonies of the <em>Cladosporium</em> sp. Our study provides new isolates that affect the <em>Cladosporium </em>sp. and<em> Botrytis </em>sp.</p>


2015 ◽  
Vol 43 (2) ◽  
pp. 494-500 ◽  
Author(s):  
Hacer Handan ALTINOK ◽  
Oktay ERDOGAN

Fusarium oxysporum is a well-known soil-borne fungi and it is difficult to control their pathogenic strains by conventional strategies. The cultures of two strains of Trichoderma harzianum (T16 and T23) were examined in laboratory conditions and with pot experiments for the control of pathogenic strains of Fusarium oxysporum f. sp. melongenae (Fomg), Fusarium oxysporum f. sp. lycopersici (Fol), Fusarium oxysporum f. sp. niveum (Fon) and F. oxysporum f. sp. melonis (Fom). The T16 and T23 strains showed significant inhibition of mycelial growth in the pathogenic strains of F. oxysporum and the maximum inhibition were recorded when the T. harzianum strain T16 was used (72.69%). Both T. harzianum strains produced volatile and non-volatile metabolites that inhibited growth of F. oxysporum strains on PDA medium. In vitro colonization study demonstrated the root-colonizing ability of these antagonists. The interaction between T. harzianum isolates (T16 and T23) and pathogenic F. oxysporum hyphae showed no overgrowth, hyphal coiling, cell wall degradation or any hyphal penetration around any of the tested F. oxysporum hyphae. Pre-treatment of soil with T16 significantly reduced the severity of Fusarium wilt disease. The disease severity in control plants reached to 90-95% whereas those of the T16-Fomg and T16-Fol treated seedlings of eggplants were 37.74% and 47.12%, respectively, on the 21st day. In this study, while both T. harzianum isolates had a considerable antagonistic effect on the tested pathogens, T16 was found to be more successful than T23. The strong repressive effect of T. harzianum (T16) towards pathogenic Fusarium oxsporum can be applied in biological control of these pathogens.


2012 ◽  
Vol 448 (2) ◽  
pp. 261-271 ◽  
Author(s):  
Benjamin Pickel ◽  
Damian P. Drew ◽  
Tom Manczak ◽  
Corinna Weitzel ◽  
Henrik T. Simonsen ◽  
...  

Thapsigargin is a major terpenoid constituent of Thapsia garganica root. Owing to its potent antagonistic effect on the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase, thapsigargin has been widely used to study Ca2+ signalling and is also a potential drug for prostate cancer. Despite its importance, thapsigargin biosynthesis in T. garganica remains unknown. In order to decipher thapsigargin biosynthesis, deep transcript sequencing (454 and Illumina) of the T. garganica root was performed, and two terpene synthases (TgTPS1/2) were identified. Functional characterization of their encoded enzymes in a metabolically engineered yeast revealed that TgTPS1 synthesized δ-cadinene, whereas TgTPS2 produced ten distinct terpenoids. However, cultivation of the TgTPS2-expressing yeast in pH-maintained conditions (pH 6–7) yielded one major oxygenated sesquiterpenoid, suggesting that formation of multiple terpenoids was caused by acidity. The major terpene product from TgTPS2 was identified as 6β-hydroxygermacra-1(10),4-diene (kunzeaol) by mass-fragmentation pattern, retention index, the nature of its acid-induced degradation and NMR. Also, recombinant TgTPS2 efficiently catalysed the synthesis of kunzeaol in vitro from farnesyl diphosphate with a Km of 2.6 μM and a kcat of 0.03 s−1. The present paper is the first report of a kunzeaol synthase, and a mechanism for the transformation of kunzeaol into the thapsigargin backbone is proposed.


2019 ◽  
Vol 54 (1) ◽  
pp. 21-35
Author(s):  
Katarína Pastirčáková

Abstract Interactions between 3 pathogenic fungi damaging horse-chestnut (Aesculus hippocastanum) leaves and fruits – Phyllosticta sphaeropsoidea, Phomopsis carposchiza, and Diaporthe padi – and the antagonistic fungus Trichoderma harzianum were studied to determine their mutual influence in vitro. Antibiosis of colonies developing on 5 nutrient media was tested. The 3 studied T. harzianum isolates differed in their antagonistic potential. although T. harzianum isolates significantly inhibited the growth of Phomopsis carposchiza, the mycelium growth of some of the re-isolates on fresh medium indicates an inadequate antagonistic effect of T. harzianum on this species. The tested Trichoderma isolates showed stronger antagonism towards the other pathogens, reflected in overgrowing of Phyllosticta sphaeropso-idea and Diaporthe padi and reducing their growth. Granulation of the cytoplasm and lysis of hyphae of the fungal pathogens were the most frequently observed effects of the interaction.


2010 ◽  
Vol 17 (2) ◽  
pp. 153-157 ◽  
Author(s):  
A. Asran-Amal ◽  
S.M. Moustafa-Mahmoud ◽  
K.K. Sabet ◽  
O.H. El Banna

1991 ◽  
Vol 66 (04) ◽  
pp. 453-458 ◽  
Author(s):  
John T Brandt

SummaryLupus anticoagulants (LAs) are antibodies which interfere with phospholipid-dependent procoagulant reactions. Their clinical importance is due to their apparent association with an increased risk of thrombo-embolic disease. To date there have been few assays for quantifying the specific activity of these antibodies in vitro and this has hampered attempts to purify and characterize these antibodies. Methods for determining phospholipid-dependent generation of thrombin and factor Xa are described. Isolated IgG fractions from 7 of 9 patients with LAs were found to reproducibly inhibit enzyme generation in these assay systems, permitting quantitative expression of inhibitor activity. Different patterns of inhibitory activity, based on the relative inhibition of thrombin and factor Xa generation, were found, further substantiating the known heterogeneity of these antibodies. These systems may prove helpful in further purification and characterization of LAs.


1992 ◽  
Vol 67 (01) ◽  
pp. 063-065 ◽  
Author(s):  
Sherryl A M Taylor ◽  
Jacalyn Duffin ◽  
Cherie Cameron ◽  
Jerome Teitel ◽  
Bernadette Garvey ◽  
...  

SummaryChristmas disease was first reported as a distinct clinical entity in two manuscripts published in 1952 (1, 2). The eponym associated with this disorder, is the surname of the first patient examined in detail and reported by Biggs and colleagues in a paper describing the clinical and laboratory features of seven affected individuals (3). This patient has severe factor IX coagulant deficiency (less than 0.01 units/ml) and no detectable circulating factor IX antigen (less than 0.01 units/ml). Coding sequence and splice junctions of the factor IX gene from this patient have been amplified in vitro through the polymerase chain reaction (PCR). One nucleotide substitution was identified at nucleotide 30,070 where a guanine was replaced by a cytosine. This mutation alters the amino acid encoded at position 206 in the factor IX protein from cysteine to serine. The non conservative nature of this substitution, the absence of this change in more than 200 previously sequenced factor IX genes and the fact that the remainder of the coding region of this gene was normal, all provide strong circumstantial evidence in favour of this change being the causative mutation in this patient. The molecular characterization of this novel mutation in the index case of Christmas disease, contributes to the rapidly expanding body of knowledge pertaining to Christmas disease pathogenesis.


Author(s):  
Markus Boel ◽  
Oscar J. Abilez ◽  
Ahmed N Assar ◽  
Christopher K. Zarins ◽  
Ellen Kuhl

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