Resumo

AYALA-VASQUEZ, MARILUZ; ARGEL-ROLDAN, LUZ EDITH; JARAMILLO-VILLEGAS, SONIA  e  MARIN-MONTOYA, MAURICIO. Genetic Diversity of Peronospora sparsa (Peronosporaceae) on Rose Crops From Colombia. Acta biol.Colomb. [online]. 2008, vol.13, n.1, pp.79-94. ISSN 0120-548X.

Downy mildew of roses is the most restrictive disease of this crop in Colombia . Although some studies have been carried out on the epidemiology of this disease, one of the fields less studied is the level of variability of its causal agent. The knowledge of this aspect is fundamental to define management strategies, especially those related with the genetic resistance and the chemical control. The objectives of this research were to confirm the taxonomic identity of the causal agent of downy mildew of rose and to deepen in the knowledge of their population structure in Colombia. Thirtyfour isolates of the pseudofungi were collected in rose crops located in Antioquia and the Savanna of Bogota and their DNA was extracted to amplify by PCR the ITS region of the DNAr using the species-specific primers PS3 and PS1. The products were used for their direct sequencing and to evaluate genetic variability by PCR-RFLP. Additionally the study was complemented throught RAPD and RAMS markers. Presence of a band of approximately 700 pb that shared a percentage of identity of 100% with sequences deposited in the GenBank, allowed to confirm the identity of the isolates as belonging to Peronospora sparsa, while the analysis of RFLP, RAPD and RAMS indicated a very low level of variability among all the isolates, concluding that the population of P. sparsa in Colombia is predominantly clonal.

Palavras-chave : rDNA; Downy mildew; Flowers; Genetic variability; ITS; Molecular markers.

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