AMPLIFICATION AND CHARACTERIZATION OF THE INTERGENIC REGIONS OF RIBOSOMAL DNA IN PENICILLIUM DIGITATUM, P. ULAIENSE AND P. ITALICUM

• Published in: Journal of plant pathology Vol. 91; no. 4; p. S4.69
• Main Authors: Ligorio, A M, Youssef, K, Nigro, F, Ippolito, A
• Format: Journal Article
• Language: English
• Published: 01.12.2009
• Subjects: Citrus; Penicillium digitatum
• ISSN: 1125-4653

Penicillium digitatum, P. italicum and P. ulaiense, are responsible for the green, blue and whisker mould of citrus fruit, respectively. A more rational approach for controlling postharvest diseases rely on the early and univocal identification of the causal agents. In P. digitatum, P. italicum and P. ulaiense, the Internal Transcribed Spacer (ITS), the most widely utilised targets to develop molecular markers, are not sufficiently variable for designing species-specific primers. By convese, the IGS regions have great potential since they are multicopy and their length (1000-4000 bp) provides considerable space for species-specific markers development. In the present work, the IGS region of the three Penicllium species was amplified and sequenced using universal primers, designed by comparing IGS flanking regions from a large number of fungi. The total length of the amplified IGS region was 2850 bp and 2600 bp for P. ulaiense and P. digitatum, respectively. A partial sequence, approximately 1800 bp, was also obtained for P. italicum. The sequenced IGS region showed tandem repeated units, five in P. ulaiense (two of 65 nucleotides and three of 35 nucleotides) and six in P. digitatum (59 nucleotides each). Species-specific primer pairs, SppenulalF/SppenulalR and Sppendig3F/Sppendig2R, designed on the most variable IGS regions, amplified amplicons of 352 and 480 bp in P. ulaiense and P. digitatum, respectively. Primer specificity was successfully tested in PCR assays using DNA from a range of fungal taxa as template. Studies are in progress to complete the IGS region sequence off! italicum.