Search

Sharka, caused by Plum pox virus (PPV), is considered one of the most serious viral diseases of stone fruits worldwide due to the great yield losses in orchards. In Rama Caída, Mendoza, a 5-year study (2007-2011) was conducted in a European plum cv D'agen orchard using samples from leaves and DAS-ELISA assay against PPV in order to determine incidence over time and spatial spread. Incidence significantly increased between 2007 and 2009, while for the next two years the increase was not statistically significant. Spatial point pattern of PPV at the plot was characterized by the occurrence of some heterogeneous clusters of infected trees located up to 65 m in the west-east direction of the rows over the five years. Point pattern and correlation type-approaches were undertaken using joint-count and Ripley's K function and showed that the detected infected plants had a disease aggregation pattern both in west-east and south-north directions, as well as within and between rows across the plot. This short-distance local dispersion would be associated with diverse factors, such as vector aphids, that were not evaluated in this study. Hence, this work can serve as a basis for further studies of sharka dispersion in Cuyo region. [ABSTRACT FROM AUTHOR]

A Plum pox virus ( PPV) isolate detected in a Japanese plum orchard in Pocito (San Juan, Argentina) was transmitted mechanically to Prunus tomentosa and Nicotiana benthamiana. DAS- ELISA and DASI- ELISA indicated the virus presence and serological relationship with D-strain isolates; IC- RT- PCR amplified a 1.2-kb fragment of the virus genome encoding the CP-3′ nc region. The analysis of the sequence showed the presence of the DAG motif at the 5′ end of the capsid protein and the Rsa I and Alu I sites at the 3′ end. The phylogenetic relationships and multiple alignment with PPV isolates from NCBI database indicated greatest (+98%) homology with the D strain and close identity with MNAT1 () USA peach isolate. The sequence analysed showed two amino acid mutations towards the 5′ N-terminus of CP (the most variable region) with respect to a consensus of PPV D-strain isolates. This is the first molecular characterization of 3′terminal genome region of PPV isolate to confirm D strain in a Japanese plum from Argentina. [ABSTRACT FROM AUTHOR]