First Occurence of Fire Blight on Apricot (<i>Prunus armeniaca</i>) in Hungary

During July 2012, a severe unusual disease symptom was observed on young shoots on apricot (<i>Prunus armeniaca</i> 10/13 hybrid) in the city of Pomáz, near Budapest. The naturally infected shoots showed typical symptoms of fire blight including terminal shoots with brown to black necrot...

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Bibliographic Details
Main Authors: Anita VÉGH, László PALKOVICS
Format: Article
Language:English
Published: AcademicPres 2013-12-01
Series:Notulae Botanicae Horti Agrobotanici Cluj-Napoca
Online Access:http://www.notulaebotanicae.ro/index.php/nbha/article/view/9183
Description
Summary:During July 2012, a severe unusual disease symptom was observed on young shoots on apricot (<i>Prunus armeniaca</i> 10/13 hybrid) in the city of Pomáz, near Budapest. The naturally infected shoots showed typical symptoms of fire blight including terminal shoots with brown to black necrotic lesions. Symptoms were the same as fire blight symptoms reported from other hosts and locations. The first occurrence of fire blight on an apricot tree in Europe was recorded in Czech Republic in 2011. Samples of the leaves and shoots with symptoms were macerated and spread on King’s medium B. After 24 hours of incubation at 26 °C, bacteria morphologically similar to <i>E. amylovora</i> were detected. Isolate induced hypersensitive reaction on tobacco (<i>Nicotiana tabacum</i> L. ‘White Burley’) leaves. Biochemical test was also used for identification, and the result of API 20E kit (Biomérieux, Marcy l’Etoile, France), demonstrate that the bacterium belongs to Enterobacteriaceae family. A pathogenicity tests were positive on young apricot shoots and immature fruits. For molecular identification of the pathogen the 16S rDNA region was amplified from isolate Ea-ApricotPo1 with a general bacterial primer pair (63f forward and 1389r reverse). The PCR products were cloned into a pGEM T-Easy plasmid vector (Promega, Madison, WI USA) and were transformed into <i>Escherichia coli</i> DH5α cells. A recombinant plasmid (2A2.5) was sequenced by M13 forward and reverse primers. The sequence was deposited in GenBank (Accession No. HF546214) and showed 99-100% sequence homology with a number of <i>E. amylovora</i> isolates, including type strain FN666575 with 100% similarity. On the basis of the symptoms, colony morphology, biochemical tests, and 16S rDNA sequence homology, the pathogen was identified as <i>E. amylovora</i>. This is a first record of a natural outbreak of fire blight on apricot in Hungary.
ISSN:0255-965X
1842-4309