title: Expression of the β-1,3-glucanase gene bgn13.1 from Trichoderma harzianum in strawberry increases tolerance to crown rot diseases but interferes with plant growth.
abstract: The expression of antifungal genes from Trichoderma harzianum, mainly chitinases, has been used to confer plant resistance to fungal diseases. However, the biotechnological potential of glucanase genes from Trichoderma has been scarcely assessed. In this research, transgenic strawberry plants expressing the β-1,3-glucanase gene bgn13.1 from T. harzianum, under the control of the CaMV35S promoter, have been generated. After acclimatization, five out of 12 independent lines analysed showed a stunted phenotype when growing in the greenhouse. Moreover, most of the lines displayed a reduced yield due to both a reduction in the number of fruit per plant and a lower fruit size. Several transgenic lines showing higher glucanase activity in leaves than control plants were selected for pathogenicity tests. When inoculated with Colletotrichum acutatum, one of the most important strawberry pathogens, transgenic lines showed lower anthracnose symptoms in leaf and crown than control. In the three lines selected, the percentage of plants showing anthracnose symptoms in crown decreased from 61 % to a mean value of 16.5 %, in control and transgenic lines, respectively. Some transgenic lines also showed an enhanced resistance to Rosellinia necatrix, a soil-borne pathogen causing root and crown rot in strawberry. These results indicate that bgn13.1 from T. harzianum can be used to increase strawberry tolerance to crown rot diseases, although its constitutive expression affects plant growth and fruit yield. Alternative strategies such as the use of tissue specific promoters might avoid the negative effects of bgn13.1 expression in plant performance.
authors.affiliation: Departamento de Biología Vegetal, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Universidad de Málaga, 29071, Málaga, Spain. mercado@uma.es.
authors.forename: José A
authors.initials: JA
authors.lastname: Mercado
authors.affiliation: IFAPA, Centro de Churriana, 29140, Málaga, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Barceló
authors.affiliation: IFAPA, Centro de Churriana, 29140, Málaga, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Pliego
authors.affiliation: Newbiotechnic S.A., 41110, Seville, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Rey
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Córdoba, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Caballero
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Córdoba, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Muñoz-Blanco
authors.affiliation: Instituto de Agricultura Sostenible, CSIC, 14080, Córdoba, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Ruano-Rosa
authors.affiliation: Instituto de Agricultura Sostenible, CSIC, 14080, Córdoba, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: López-Herrera
authors.affiliation: IFAPA, Centro Las Torres-Tomejil, 41200, Seville, Spain.
authors.forename: Berta
authors.initials: B
authors.lastname: de Los Santos
authors.affiliation: IFAPA, Centro Las Torres-Tomejil, 41200, Seville, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Romero-Muñoz
authors.affiliation: Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", IHSM-UMA-CSIC, Universidad de Málaga, 29071, Málaga, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Pliego-Alfaro
mesh_terms: D060467:Disease Resistance / Q000276:immunology*; D031985:Fragaria / Q000254:growth & development* / Q000276:immunology / Q000382:microbiology; D005638:Fruit / Q000254:growth & development / Q000276:immunology / Q000382:microbiology; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D043326:Glucan 1,3-beta-Glucosidase / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000254:growth & development / Q000276:immunology / Q000382:microbiology; D018517:Plant Roots / Q000254:growth & development / Q000276:immunology / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000254:growth & development* / Q000276:immunology / Q000382:microbiology; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D043326:Glucan 1,3-beta-Glucosidase
keywords: Anthracnose; Colletotrichum acutatum; Fragaria × ananassa; Fungal resistance; Rosellinia necatrix; Transgenic plants; White root rot