|
|
|
|
|
| Montealegre,Jaime; Valderrama,Luis; Sánchez,Soledad; Herrera,Rodrigo; Besoain,Ximena; Pérez,Luz María. |
| Biocontrol of Rhizoctonia solani in tomatoes cultivated under greenhouse and field conditions was analyzed using the Trichoderma harzianum mutants Th650-NG7, Th11A80.1, Th12A40.1, Th12C40.1 and Th12A10.1 and ThF2-1, respectively. Their innocuousness on tomato cultivars 92.95 and Gondola (greenhouse assays), and on cultivar Fortaleza (field assays) was established. Alginate pellets (1.7 g pellets/L soil) containing c.a1 x 10(5) colony forming units (cfu)/g pellet were applied to a soil previously inoculated with R. solani at transplant (greenhouse) or to a naturally infected soil (field). Controls considered parental wild strains, a chemical fungicide and no additions. Th11A 80.1, Th12A10.1 and Th650-NG7 prevented the 100% mortality of tomato plants cv.... |
| Tipo: Journal article |
Palavras-chave: Bioantagonism; Field assays; Greenhouse assays; Root rot; Tomato. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582010000200001 |
| |
|
|
| Zaldívar,Mercedes; Velásquez,Juan Carlos; Contreras,Inés; Pérez,Luz María. |
| A mutant of the native fungus Trichoderma aureoviride, 7-121, selected for its overproduction of extracellular cellulase and ß-glucosidase (cellobiase) was obtained. In shake flask cultures, production of endoglucanase, filter paper activity and cellobiase increased two to four- fold as compared with the wild type strain. The mutant strain is stable and grows rapidly in liquid as well as in solid culture media. Enzyme yields were best when pH was controlled so that it did not fall bellow pH 3.5. Cellobiase production by this mutant is particularly high (approximately 5 U/ml) as compared to other Trichoderma, strains, which makes it a suitable candidate for waste cellulose degradation. In addition, the mutant strain showed enhanced production of fungal cell... |
| Tipo: Journal article |
|
| Ano: 2001 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582001000300011 |
| |
|
|
| Montealegre,Jaime R.; Reyes,Rodrigo; Pérez,Luz María; Herrera,Rodrigo; Silva,Polyana; Besoain,Ximena. |
| Bacteria from the rhizoplane and surrounding soil of healthy and Rhizoctonia solani diseased tomato plants, cropped in greenhouse of the V Region of Chile, were collected. The best bacterial strains, based on their ability to control development of three R. solani isolates (identified as belonging to the anastomosis groups AG-2-1, AG‑4), were identified as B. subtilis (one isolate) and B. lentimorbus (two different isolates). All bacterial isolates resulted effective for the in vitro control of growth of all R. solani isolates, where the control mechanisms used by the bacteria do not involve the secretion of fungal cell wall hydrolytic enzymes. R. solani AG-2-1 was more sensitive than R. solani AG-4. On the other hand, all bacteria grew well in... |
| Tipo: Journal article |
|
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582003000200006 |
| |
|
|
| Montealegre,Jaime R; Herrera,Rodrigo; Velásquez,Juan Carlos; Silva,Polyana; Besoaín,Ximena; Pérez,Luz María. |
| Trichoderma harzianum 650 (Th650) and Paenebacillus lentimorbus 629 (Pl629) selected earlier for their ability to control Rhizoctonia solani, Fusarium solani and F. oxysporum in vitro, were applied alone or combined with solarization (summer assay) and/or with methyl bromide (MeBr) (summer and winter assays) to a soil with a high inoculum level, for the control of tomato root rot caused by the complex F. oxysporum f. sp. lycopersici - Pyrenochaeta lycopersici - Rhizoctonia solani. Evaluations were also performed independently for root damage caused by P. lycopersici, and also for R. solani in the summer assay. MeBr decreased tomato root damage caused by the complex from 88.7% to 21.2% and from 78.4% to 35.7% in the summer and in the winter assay,... |
| Tipo: Journal article |
Palavras-chave: Fusarium oxysporum; Lycopersicon esculentum; Pyrenochaeta lycopersici; Rhizoctonia solani; Solarization. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582005000300004 |
| |
|
|
| Besoain,Ximena A; Pérez,Luz María; Araya,Antonio; Lefever,Llacolén; Sanguinetti,; Montealegre,Jaime R. |
| The obtainment of 30 new strains from native Trichoderma harzianum after UV light irradiation (UV-A and UV-C), and of 82 strains resulted from protoplast fusion were accomplished. The new strains, initially selected for their growing rate under low temperature and high pH conditions, as well as for their innocuousness on tomato plants, were tested for in vitro inhibition of Pyrenochaeta lycopersici in dual cultures and due to secretion of volatile and diffusible metabolites. All the UV-A and UV-C selected candidate mutants were innocuous to tomato plants, but none of them showed improvement in their biocontrol activity on P. lycopersici. Th12A20.1 increased 1.3 and 1.9 fold the total fresh weight of Fortaleza tomato plants when compared to its parental... |
| Tipo: Journal article |
Palavras-chave: Corky root; Mutagenesis; Tomato diseases; Trichoderma; Volatile and diffusible metabolites. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582007000400013 |
| |
|
|
| Roco,Angela; Pérez,Luz María. |
| The in vitro biocontrol ability of Trichoderma harzianum on the phytopathogen Alternaria alternata improved in the presence of the growth regulators gibberellic acid (GA3), or indolacetic acid (IAA) or benzylaminopurine (BAP) or foliar nutrient at concentrations similar or higher than those used at the field level. These plant hormones decreased the secretion of endopolygalacturonase (endo-PG) of A. alternata by approximately 20%, did not modify endochitinase (endo-CH) secretion of T. harzianum and did not alter germination of conidia or mycelia growth of any of these fungi. The presence of T. harzianum decreased endo-PGase secretion of A. alternata by about 50%. This inhibitory effect was independent of the presence of growth regulators. The level of... |
| Tipo: Journal article |
|
| Ano: 2001 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582001000200006 |
| |
|
|
| Herrera,Rodrigo; Núñez,David; Romero,Natalia; Besoain,Ximena; Pérez,Luz María; Montealegre,Jaime. |
| The germination of conidia in wild-type (Th11, Th12 and Th650) and mutant (Th11A80.1, Th12A10.1 and Th650-NG7) strains of Trichoderma harzianum that were exposed to different commercial fungicides was studied. All wild-type and mutant Trichoderma strains were germinated in the presence of 1,700 mg L-1 of pencycuron. The wild-type strains Th12 and Th650 and the corresponding mutant strains Th12A10.1 and Th650-NG7 were sensitive to all concentrations of iprodione and metalaxil + mancozeb. The EC50 (Median Effective Concentration) values for the different fungicides were between 10-1 and 10-4 less than the concentrations recommended for field applications; one exception was Phyto-fos on Th650-NG7, where this ratio was 0.72. These results establish whether... |
| Tipo: Journal article |
Palavras-chave: Biocontrol; Biocontrol agents; Control of tomato root diseases; Fungicides; Fungicide tolerant Trichoderma; Integrated management. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202012000300016 |
| |
|
|
|
