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Electronic Journal of Biotechnology
Universidad Católica de Valparaíso
ISSN: 0717-3458
Vol. 10, No. 4, 2007, pp. 604-617
Bioline Code: ej07059
Full paper language: English
Document type: Research Article
Document available free of charge

Electronic Journal of Biotechnology, Vol. 10, No. 4, 2007, pp. 604-617

 en New strains obtained after UV treatment and protoplast fusion of native Trichoderma harzianum check for this species in other resources : their biocontrol activity on Pyrenochaeta lycopersici check for this species in other resources
Besoain, Ximena A.; Pérez, Luz María; Araya, Antonio; Lefever, Llacolén; Sanguinetti, Melina & Montealegre, Jaime R.

Abstract

The obtainment of 30 new strains from native Trichoderma harzianum check for this species in other resources 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 check for this species in other resources 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 strains Th12 and Th11, respectively. The selected candidate mutants obtained through protoplast fusion were also innocuous to tomato plants, but only ThF1-2 and ThF4-4 inhibited 1.3 fold (in dual cultures) and 5 fold (due to secretion of volatile metabolites) the growth of P. lycopersici, respectively, in relation to the mean inhibitory effect of both parents. Therefore, these candidate mutants could be included in experiments under field conditions.

Keywords
corky root, mutagenesis, tomato diseases, Trichoderma, volatile and diffusible metabolites.

 
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