Abstract

MORENO-VELAZQUEZ, Magnolia et al. PCR detection of Guignardia bidwellii, causal agent of grape black rot. Rev. mex. fitopatol [online]. 2019, vol.37, n.3, pp.383-398.  Epub Sep 30, 2020. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.1905-5.

Guignardia bidwellii (anamorph Phyllosticta ampelicida) is the etiological agent of grape black rot, a disease of economic importance in Europe and a quarantine pest for Mexico. The identification of the anamorphic state by morphological characteristics is complicated, due to the similarity among species of the same genus, for example with the cosmopolitan endophyte G. endophyllicola (P. capitalensis), therefore it is necessary to have quick and specific diagnostic tools. For this purpose, a molecular marker based on single nucleotide polymorphisms (SNP) in the ITS region of the rDNA was developed, where the Bidwell and Ampel2 primers were designed. The PCR amplification generates a fragment of 173 bp, specific to G. bidwellii f. euvitis. The validation of the method showed that there is no cross amplification with closely related phytopathogenic fungi or with the genome of grapevine. The technique was sensitive to detect up to 30 pg μL-1 of DNA from monosporic cultures and in mixture of plant tissue. This diagnostic procedure is presented as a fast and specific option for the monitoring, and detection of G. bidwellii f. euvitis in support of prevention, management, quarantine and eradication strategies of the disease.

Keywords : Phyllosticta ampelicida; molecular diagnosis; ITS; Vitis spp.