Identification of a new cotton disease caused by an atypical cotton leafroll dwarf virus in Argentina

An outbreak of a new disease occurred in cotton (Gossypium hirsutum) fields in northwest Argentina starting in the 2009-10 growing season and is still spreading steadily. The characteristic symptoms of the disease included slight leaf rolling and a bushy phenotype in the upper part of the plant. In this study, we determined the complete nucleotide sequences of two independent virus genomes isolated from cotton blue disease (CBD)-resistant and -susceptible cotton varieties. This virus genome comprised 5,866 nucleotides with an organization similar to that of the genus Polerovirus and was closely related to cotton leafroll dwarf virus, with protein identity ranging from 88 to 98%. The virus was subsequently transmitted to a CBD-resistant cotton variety using Aphis gossypii and symptoms were successfully reproduced. To study the persistence of the virus, we analyzed symptomatic plants from CBD-resistant varieties from different cotton-growing fields between 2013 and 2015 and showed the presence of the same virus strain. In addition, a constructed full-length infectious cDNA clone from the virus caused disease symptoms in systemic leaves of CBD-resistant cotton plants. Altogether, the new leafroll disease in CBD-resistant cotton plants is caused by an atypical cotton leafroll dwarf virus.Fil: Agrofoglio, Yamila Carla. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Delfosse, Verónica Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Casset, María Andrea. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Hopp, Horacio Esteban. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Kresic, Iván Bonacic. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Fisiología, Biología Molecular y Celular; ArgentinaFil: Distéfano, Ana Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Fisiología, Biología Molecular y Celular; Argentin