Gooseberry (Ribes uva-crispa L.) is a commonly grown fruit tree or bush in the Czech Republic. Colletotrichum acutatum J. H. Simmonds is a polyphagous fungal plant pathogen. This pathogen has been reported causing anthracnose on strawberry in the Czech Republic (2), and recently it has become an important pathogen on the fruits of apple and tomato (4). In 2012, anthracnose symptoms were noticed on fruits of gooseberry (locality Pribyslavice, near Brno). The symptoms on fruit surfaces were round, brown, shriveled, sunken spots of 1.2 to 2.0 cm, with orange conidial masses on the spots. The pathogen was isolated from symptomatic fruits on PDA and cultured at 25 ± 2°C. The color of colonies varied with age from white to gray with occurrence of orange conidial masses. Conidia were colorless and fusiform, size 13 to 17 × 4 to 5 μm (n = 100). The morphological characteristics classified the pathogen as a Colletotrichum sp. To fulfill Koch's postulates, 25 disinfested healthy gooseberry fruits were pinpricked by sterile needle and 10 μl of spore suspension (1 × 105 conidia ml–1) was inoculated by pipetting into the wound. Control fruits were treated with sterile distilled water. The fruits were transferred to a growth cabinet and maintained at a temperature of 25 ± 2°C, relative humidity 70 ± 5%. Similar anthracnose symptoms were observed on all of gooseberry fruits a week after inoculation, whereas no symptoms appeared on control fruits. The pathogen was reisolated from infected fruits. Species determination of the isolates was confirmed by PCR. Specific primers designed in region ITS1, the 5.8S RNA gene, and region ITS2 of the pathogen DNA were selected. Specific primers CaInt2 and ITS4 were used to identify C. acutatum (3), and primers CgInt and ITS4 were used to determine C. gloeosporioides isolate CCM 177 (1), which was used as a control. Our isolates yielded PCR products (size 490 bp) only with primers designed for C. acutatum. The C. gloeosporioides isolate yielded PCR product (size 450 bp) only with CgInt and ITS4 primers. PCR products were sequenced and identified with the BLAST program. The sequence of the gooseberry fruit isolates (Accession No. JX843763 and JX843764) matched with 100% similarity to the C. acutatum sequences in GenBank. To our knowledge, this is the first report of C. acutatum sensu lato on gooseberry fruits in the Czech Republic. This pathogen can endanger the production of gooseberry fruits in this region. References: (1) P. R. Mills et al. FEMS Microbiol. Lett., 98:137, 1992. (2) D. Novotný et al. Plant Dis. 91:1516, 2007. (3) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (4) J. Víchová et al. Plant Dis. 96:769, 2012.
Evaluation of the Growth Dynamics and Morphological Characteristics of Genetic Sources of Silybum marianum (L.) Gaertn
