Detection and molecular characterization of Grapevine yellow speckle viroid 1 isolates infecting grapevines in Brazil.

Abstract Presently, Hop stunt viroid(HSVd) and Citrus exocortis viroid (CEVd) are the only viroids reported to infect grapevines (Vitis spp.) in Brazil, among the seven viroid species already reported infecting this host in other countries. All grapevine viroid diseases are graft-transmissible and can induce losses especiallywhenassociatedwithviruses.Theaimofthisworkwas to confirm infection by Grapevine yellow speckle viroid 1(GYSVd-1) in grapevine samples exhibiting yellow speckle symptoms in the leaves and in asymptomatic samples sequenced by next generation sequencing (NGS). The occurrence of this viroid in Brazil was further investigated in a second study. Total RNAs and dsRNAs were extracted from five symptomatic plants and 16 asymptomatic samples, respectively. Specific primers were used for RT-PCR and amplified DNA fragments were cloned and sequenced by the Sanger method. Eleven complete nucleotide sequences of GYSVd-1 isolates (366 ?367 nt) were obtained from NGS and from RT-PCR amplicons. Comparisons showed high identities (95.9 ?100 %) among ten isolates and an identity of 87.2 ?90.4 % with a divergent isolate (RM-BR). Phylogenetic analyses placed GYSVd-1 isolates in four clusters (types 1, 2, 3 and 4). All GYSVd-1 infections were confirmed by conventional RT-PCR and RT-qPCR using specific oligonucleo-tides and a labeled probe. This is the first report and molecular characterization of GYSVd-1 infecting grapevines in Brazil, and our survey indicates that this viroid could be widespread in the major grape producing regions of Brazil. Keywords GYSVd-1 . Incidence . Next generation sequencing. Secondary structure. Vine.

Detection of ochratoxin A in tropical wine and grape juice from Brazil.

Ochratoxin A (OTA) is the main mycotoxin found in grapes, wines and grape juices and is considered one of the most harmful contaminants to human health. In this study, samples of tropical wines and grape juices from different grape varieties grown in Brazil were analysed for their OTA content by high-performance liquid chromatography. The detection and quantification limits for OTA were 0.01 and 0.03 ?g L?1 respectively. OTA was detected in 13 (38.24%) of the samples analysed, with concentrations ranging from <0.03 to 0.62 micron g L-1. OTA was not detected in any of the grape juice samples. Most of the red wine samples proved to be contaminated with OTA (75%), while only one white wine sample was contaminated. However, the OTA levels detected in all samples were well below the maximum tolerable limit (2 micron g L-1) in wine and grape juice established by the European Community and Brazilian legislature. The results of this study indicate a low risk of exposure to OTA by consumption of tropical wines and grape juices from Brazil.