Lippia citriodora HBK (Verbenaceae) is an aromatic plant, with white-lilac flowers and pale-green leaves having a strong lemon scent, native to South America. This species is known to be susceptible to Alfalfa mosaic virus (AMV), responsible of bright yellow mosaic on leaves, necrotic spots and stunting. In the last decade, AMV has been frequently found infecting L. citriodora crops in the Herb Garden of Casola-Valsenio (Emilia-Romagna region).To confirm AMV presence, symptomatic leaves collected from two crops in 2006 and again in 2011, were tested in PAS-ELISA. To determine specific subgroup, IC-RT-PCR was performed using a polyclonal serum against an AMV isolate from lettuce, combined with two AMV specific primer pairs: a DNA fragment of c.a. 750 bp, covering the entire coat protein gene (CP), was obtained. Products were gel purified, cloned in pGEMT Easy vector (Promega, USA) and sequenced on both strands. Comparison of CP sequences of AMV-L. citriodora isolates with referenced sequences of AMV isolates, revealed the maximum (98.2-97.0%) nucleotide identity with isolates of subgroup I, compared with 95.5-94.0% of subgroup IIA and 95.2% (average between the two sequences) of subgroup IIB. These results confirm that AMV isolates infecting L. citriodora belong to subgroup I, which includes all isolates found in Italy until now. AMV presence could be explained by accidental vegetative propagation of latent infected plants or aphid transmission, although two independent events of infection likely affected at different time the crops of L. citriodora analyzed, since 1.2% of nucleotide difference between the two isolate has been detected.
Molecular characterization of italian isolates of alfalfa mosaic virus infecting Lippia citriodora
CAVICCHI, LISA;BELLARDI, MARIA GRAZIA
2012
Abstract
Lippia citriodora HBK (Verbenaceae) is an aromatic plant, with white-lilac flowers and pale-green leaves having a strong lemon scent, native to South America. This species is known to be susceptible to Alfalfa mosaic virus (AMV), responsible of bright yellow mosaic on leaves, necrotic spots and stunting. In the last decade, AMV has been frequently found infecting L. citriodora crops in the Herb Garden of Casola-Valsenio (Emilia-Romagna region).To confirm AMV presence, symptomatic leaves collected from two crops in 2006 and again in 2011, were tested in PAS-ELISA. To determine specific subgroup, IC-RT-PCR was performed using a polyclonal serum against an AMV isolate from lettuce, combined with two AMV specific primer pairs: a DNA fragment of c.a. 750 bp, covering the entire coat protein gene (CP), was obtained. Products were gel purified, cloned in pGEMT Easy vector (Promega, USA) and sequenced on both strands. Comparison of CP sequences of AMV-L. citriodora isolates with referenced sequences of AMV isolates, revealed the maximum (98.2-97.0%) nucleotide identity with isolates of subgroup I, compared with 95.5-94.0% of subgroup IIA and 95.2% (average between the two sequences) of subgroup IIB. These results confirm that AMV isolates infecting L. citriodora belong to subgroup I, which includes all isolates found in Italy until now. AMV presence could be explained by accidental vegetative propagation of latent infected plants or aphid transmission, although two independent events of infection likely affected at different time the crops of L. citriodora analyzed, since 1.2% of nucleotide difference between the two isolate has been detected.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
