Characterisation of Penicillium digitatum isolates for fungicide resistance
P. Sánchez-Torres and J.J. Tuset.
Journal of Plant Pathology Volume 90 (2, Supplement) August 2008, Book of Abstract, 9th International Congress of Plant Pathology, August 24-29, 2008 Torino,Italy,. 507 pages.
2008
บทคัดย่อ
Characterisation of Penicillium digitatum isolates for fungicide resistance
Citrus green mould, caused byPenicillium digitatumis one ofthe most important postharvest diseases of citrus. Fungicide treatments are a key component in the integrated management of many plantdiseases,therefore the appearance of resistance has become an important factor in limiting the efficacy. The most recent thought for fungicide resistance is based on active eflux of these toxic compounds due to transporters like ABC (ATP binding cassette) or MFS (Major Facilitator Superfamily) that havea remarkablybroad susbstrate specificity although they can also transport specific compounds. Despite the size of the economic losses caused by this fungus, another important aspect is that some of these resistant genes may be involved in pathogenicty/ virulence. To uncover these factors relevant to fungicide resistance we analysed at the molecular level the differences between resistant and sensitiveP. digitatumstrains. A single point mutation in theb-tubulin gene was found to be reponsible for thiabendazol resistance while different mutations were identified in two ABC transporters, PMR1 and PMR5. The method involved detection of the presence of the tandem repeat of five copies of a 126 bp transcriptional in the promoter region of PdCYP51, leading to overexpression of this gene and conferment of DMI resistance to the fungus. The absence of this repeat does not imply thatP. digitatumis DMI-sensisitive. In fact, many isolates with a high degree of resistance to DMIs only exhibited one repeat, supporting the hypotheis that many factors could be involved in fungicide resistance.