Authors
M. C.
Herranz
,
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, Avenida de los Naranjos s/n, 46022, Valencia, Spain
;
D.
Maeso
and
J.
Soria
,
INIA Las Brujas, Ruta 48 Km 10, Rincón del Colorado, Departamento de Canelones, Uruguay
; and
V.
Pallás
,
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, Avenida de los Naranjos s/n, 46022 Valencia, Spain
Peach latent mosaic viroid (PLMVd) (2) is widely distributed and causes yellow, chlorotic mosaics and delayed foliation, flowering, and ripening. Infected fruits display a cracked suture and are often dented, misshapen, frequently flattened, and discolored. In the greenhouse, PLMVd natural isolates are divided into severe or latent strains depending on whether they induce leaf symptoms on seedlings of the peach indicator GF-305. PLMVd was detected in 2001 during a survey in three locations in the Canelones Department, the main peach producing area in Uruguay. Fifty samples were tested for the presence of five viruses: Prunus necrotic ringspot virus (PNRSV), Prune dwarf virus (PDV), American plum line pattern virus (APLPV), Plum pox virus (PPV) and Apple chlorotic leaf spot virus (ACLSV); samples were also tested for the viroids affecting stone fruits, Hop stunt viroid (HSVd) and PLMVd. The analyses were completed with molecular hybridization using specific nonisotopic riboprobes for each virus (4). PLMVd, undescribed in Uruguay, was detected in 9 of 50 samples in three peach cultivars, Scarlet Pearl, EarliGrande, and Barcelo. The PLMVd-positive sample for ‘Scarlet Pearl’ showed mild mosaic symptoms on leaves whereas the two PLMVd-positives of ‘EarliGrande’ showed clear calico type symptoms. The remaining PLMVd-positive samples belonged to ‘Barcelo’ and showed no symptoms or mild chlorosis. The first two cultivars were imported from the United States, a source with a high percentage of PLMVd infections in peach germ plasm (1). In five of nine PLMVd-positive samples, the viroid occurred with PNRSV and in one with PDV and PNRSV. PLMVd has previously been reported in Brazil (3), but to our knowledge, this is the first report of PLMVd in Uruguay. These results reveal the importance of following strict sanitary practices with plant material used for propagation. Molecular tools are available to prescreen scion and rootstock sources for PLMVd.
References: (1) M. L. Badenes and G. Llácer. Acta Hortic. 309:565, 1998. (2) R. Flores et al. Res. Virol. 141:109, 1990. (3) A. Hadidi et al. Plant Dis. 81:154, 1997. (4) V. Pallás et al. Detection of plant RNA viruses by non-isotopic dot-blot hybridization. Pages 461--468 in: Plant Virus Protocols: From Virus Isolation to Transgenic Resistance. G. Foster and S. Taylor, eds. Humana Press, Totowa, NJ. 1998.
