Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 3.23

SET UP OF A RAPID PCR-BASED DIAGNOSTIC METHOD TESTED ON A LARGE ITALIAN PYRICULARIA GRISEA (COOKE) SACC. COLLECTION

PIOTTI E.*, RIGANO M.M.*, RODINO D.**, RODOLFI M.**, CASTIGLIONE S.*, PICCO A. M.**

*) Dipartimento di Biologia, Università di Milano, Via Celoria 26, 20133 Milano, Italia

francesco.sala@unimi.it

**) Dipartimento di Ecologia del Territorio e degli Ambienti Terrestri, Sez. di Micologia, Università di Pavia, Via S. Epifanio 14, 27100 Pavia, Italia

apicco@et.unipv.it

rice blast, Pyricularia grisea, diagnostic test, heminested-PCR

The rice blast pathogen (Pyricularia grisea) causes considerable damage in rice crops in Northern Italy. Control of blast disease is based on preventive spraying with fungicides. Symptoms of blast infection are lesions on leaves, nodes, neck or panicle of susceptible rice cultivars. These symptoms might be mistaken with those of other rice pathogens like Alternaria spp. and Bipolaris oryzae. Therefore, specific PCR-based methods to detect P. grisea on rice would be helpfull. A PCR primer pair was designed on the bases of the P. grisea specific Pwl 2 gene (accession number U26313). The primer pair amplifies a DNA fragment only in the presence of P. grisea DNA, but not of other parasitic fungi or of rice DNA. Moreover a further specific PCR primer was selected to increase the sensitivity threshold by using a heminested-PCR. Because of P. grisea high variability with respect to infectivity, forty-five different isolates from different Italian rice cultivars were characterised using rep-PCR (repetitive-element-based polymerase chain reaction). Statistical analysis of the results allowed the identification of nine different P. grisea lineages. The PCR-based method was tested successfully on all members of the nine lineages as well as on infected rice collected in the field.

The results provide the molecular bases for the production of a “kit” to detect and identify Pyricularia grisea in rice.