engleski

First report of Tilletiopsis pallescens causing white haze on apple in Croatia

During 2014, apples ‘Pink Lady®’, showing white haze (WH) symptoms, were harvested in an orchard near Vratisinec (Croatia). Fungi were isolates from symptomatic epidermal tissue on Rose Bengal Chloramphenicol agar. After 7 days of incubation in the dark at 26°C, from whitish to cream colonies with irregular margin, single spore were isolated and transferred on Potato dextrose agar (PDA). Pathogenicity was tested on 20 apples ‘Pink Lady®’ and the pathogen was inoculated by aerosol diffusion on the sterilized surface. Symptoms occurred and T. pallescens was reisolated from inoculated fruit on PDA. Control fruits were symptomless. After 7 days at 26°C, the colonies and the morphology of conidia were the same as those of the original isolates. PCR amplification was carried out, from single spore DNA extraction, using universal primers ITS1 and ITS4. Two amplified sequences (AN KR269863 and KR269864) were blasted in Genbank obtaining 100% homology with strains of Tilletipsis pallescens. To confirm the species DNA sequences were aligned with CLUSTAL W with closely related species of Tilletiopsis (T. pallescens GQ281316.1, DQ317636.1 ; T. washingtoniensis DQ025483.1 ; T. lilacina AB025683.1, AB025689.1T ; T. cremea AB025690.1 ; and an undefined species Tilletiopsis sp. GQ281313.1) and a phylogenetic analysis with the Neighbor Joining method based on Maximum Composite Likelihood model (bootstrap 1, 000) was performed (supplementary material). The phylogenetic tree confirmed the identity of the isolates to the species Tilletiopsis pallescens. To our knowledge, this is the first report of Tilletiopsis pallescens causing postharvest white haze on apple in Croatia.

Tilletiopsis pallescens; apple; Croatia; postharvest

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