Strong preference for the integration of transforming DNA via homologous recombination in Trichoderma atroviride. Issue 10 (October 2020)

• Record Type: Journal Article
• Authors: Esquivel-Naranjo, Edgardo Ulises; Herrera-Estrella, Alfredo
• Is Part Of: Fungal biology. Volume 124:Issue 10(2020)
• Page Start: 854
• Page End: 863
• Publication Date: 2020-10
• Subjects: Transformation -- Recombination -- Trichoderma -- Light-perception -- Biocontrol -- Transforming DNA; Mycology -- Periodicals; Fungi -- Periodicals; 579.505
• DOI: 10.1016/j.funbio.2020.07.001
• Languages: English
• ISSNs: 1878-6146

Abstract

Abstract: Trichoderma species play important roles in nature as plant growth promotors and antagonists of phytopathogenic fungi, and are used as models to study photomorphogenesis. Molecular tools have been implemented to manipulate and improve these fungi. However, instability of transformants or very low frequency of homologous recombination has been reported. Here, we report the fate of transforming DNA, demonstrating that it can follow two different fates. When a vector contains sequences also present in the Trichoderma atroviride genome, it mainly integrates by homologous recombination generating stable recombinant strains. In contrast, vectors with no sequence homology to the T. atroviride genome generate unstable transformants, losing the transforming DNA in the first generation of conidia produced without selection where, surprisingly, the vector behaves as autoreplicative. Integration by homologous recombination was demonstrated when transformants were generated with a truncated version of the blr 2 gene, resulting in insertional mutants with phenotypes identical to those of knockout mutants. Our results indicate that T. atroviride is highly efficient in integrating DNA by homologous recombination and that plasmid vectors with no sequence homology to the genome are maintained for several generations in T. atroviride if kept under selective pressure even though they lacked fungal autonomous replication sequences.