Identification and pathogenicity of Penicillium spp. isolated from onion seeds

FONTANA, LORENA I.; TARNOWSKI, CHRISTIAN G.; CALIGIORE GEI, PABLO F.; VALDEZ, JORGE G.

Foz do Iguaçu

Congreso; XXII International Congress of Genetics; 2018

International Genetics Federation (IGF)

Onion seed production is performed over 600 ha in Mendoza and San Juan provinces,Argentina. This arid region, with a rainfall regime of less than 200 mm each year, issuitable for seed production. One of the main reasons for this is that few pathogens cangrow and affect seeds in this climate. Penicillia is reported as an ubiquos complex offungi that may appear in these conditions. According to currently taxonomic schemes, P.albocoremium has been identified as a pathogen for onion. Colonies of Penicillia arenormally found on blotter tests and reported as contaminants, but no evidence has beenfound in the bibliography about efforts to identify pathogenic seedborne strains ofPenicillium on onion seeds. To answer these questions, 72 samples of onion seeds weresubmitted to deep freeze blotter, and growing colonies of Penicillium isolated. Penicilliawas absent in 16 % of the samples, while 55% had an incidence of 1 to 15 %; only 4%presented more than 60% of incidence. The incidence of Penicillia were not related togermination percentages. Secondary metabolites will be extracted and strains will besorted into groups by TLC, comparing to P. albocoremium type cultureschemotaxonomically. Genetic studies will also be performed, estimating the phylogeneticrelationships among species. To achieve this, parts of the RPB1, RPB2, calmodulin(cmd) and β-tubulin genes will be amplified and sequenced. Sequences will be comparedwith ex Type strains present in GenBank®. Pathogenicity tests will be carried on usingsterilized onion bulbs inoculation.