Indexação biológica múltipla e RT-PCR para detecção de virus latentes em macieiras

Abstract

This study aimed to evaluate the suitability of a multiple biological indexing method of latent apple viruses. The method consisted of grafting five indicator species and two buds of the plant to be indexed on to one rootstock. Results showed that the sensitivity and efficacy of the MBI is adequate for reliable detection of Apple stem grooving virus, (ASGV), Apple stem pitting virus (ASPV) and Apple chlorotic leaf spot virus (ACLSV) of mother plant stock in certification programs. Sample analysis by RT-PCR confirmed the results of the diagnosis of ASPV and ASGV by multiple biological indexing. However, it did not detect ACLSV diagnosed by LL-S5 in three out of nine analyzed accessions. The coat protein gene of one of the accessions studied was cloned and sequenced. The annealing sites of primers used in unsuccessful amplification attempts were compared with data of the Genbank to explain the non-amplification of certain ACLSV isolates. Copyright by the Brazilian Phytopathological Society.