First report of spot lesion of wheat caused by Pyrenophora teres f. sp maculata observed in Argentina

• Autores: Perello, Analia Edith; Couretot, Lucrecia Alejandra; Curti, Analía; Uranga, Juan Pablo; Consolo, Verónica Fabiana
• Año de publicación: 2019
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Crop Protection 122 : 19–22 (Agosto 2019)
• Materia: Trigo; Triticum Aestivum; Pyrenophora Teres; Enfermedades de las Plantas; Wheat; Plant Diseases; Argentina
• Institución: Instituto Nacional de Tecnología Agropecuaria

Pyrenophora tritici-repentis, causal agent of tan spot, is the species commonly associated with leaf spotting symptoms on wheat (Triticum aestivum L.) worldwide and in Argentina. On the other hand, P. teres is a major constraint on barley (Hordeum vulgare L.) production, however the pathogen has not been reported in association with wheat crop in Argentina. In 2018, following a routine survey of wheat fields, leaves showing symptoms compatible with those caused by Pyrenophora spp. were observed in the principal wheat production areas in Buenos Aires and Entre Rios Provinces of Argentina. The disease incidence varied from 30% to 80%. Symptomatic wheat plants were collected from production fields and spotted foliar tissue with symptoms was plated onto PDA 2% growth medium. The isolates were tentatively identified as putative Pyrenophora spp. based on its colonies and conidia characteristics. Given the possibility of confusion by similar characteristics between some Pyrenophora species that infect wheat plants, the aim of this work was to clarify the identity of the fungus infecting this crop. In this study, we were able to confirm field observations in greenhouse assays on wheat plants using the fungal isolates. The seedling symptoms rate under artificial inoculation of five commercial wheat varieties was 100%. Pathogenicity tests and morphological studies as well as analyses indicated that the disease was caused by Pyrenophora teres. Molecular identification of the two isolates was doubled checked by PCR. First, the internal transcribed spacer (ITS) amplification and sequencing and specific PCR assay using PTT and PTM primers allowed to confirm that two monosporic isolates were P. teres f. maculata. This is a novel disease on wheat in Argentina caused by this pathogen. This finding is of great importance from the epidemiological point of view of the biodiversity of the fungus and also to contribute with the future management of the disease.
EEA Pergamino
Fil: Perello, Analia Edith. Universidad Nacional de la Plata. Facultad de Ciencias Agrarias y Forestales. Departamento de Ciencias Biológicas. Centro de Investigaciones de Fitopatología. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigaciones de Fitopatología; Argentina
Fil: Couretot, Lucrecia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Departamento de Fitopatología; Argentina
Fil: Curti, Analía. CBAgro Servicios Agrícolas; Argentina
Fil: Uranga, Juan Pablo. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Cátedra de Cerealicultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina
Fil: Consolo, Verónica Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnología; Argentina