Phomopsins: an overview of phytopathological and chemical aspects, toxicity, analysis and occurrence

Phomopsis leptostromiformis, and its teleomorph Diaporthe toxica, is a lupin pathogen that\r\ncauses stem blight in young lupins and, as a saprophyte, has been detected on dead lupine\r\nmaterial. Under favourable conditions, the fungus produces phomopsins (PHOs), a family of\r\nmacrocyclic hexapeptide mycotoxins capable of binding tubulin through the tripeptide side\r\nchain. The toxic effects appear largely confined to the liver. In particular, the ingestion of\r\nPHO contaminated lupin stubble has been linked to lupinosis, a debilitating disease of sheep\r\n(the most sensitive animal) characterised by disorientation, blindness, lethargy, and eventually\r\ndeath. The chemical structures of PHO A, B and D have been identified. Analytical methods\r\nto determine PHOs are mainly enzyme-linked immunosorbent assays or chromatographic\r\nseparations, in combination with ultraviolet and mass spectrometric detection. The data about\r\nthe PHOs occurrence are limited to Australia, restricted to lupin seed. Only one survey has\r\nbeen carried out on lupin seeds and flours from the Swiss market. Not many strategies have\r\nbeen developed to limit lupin seed contamination. Efforts devoted to control lupinosis in\r\nAustralia focused on the development of cultivars resistant to Phomopsis infection. There are\r\nfew examples in literature of decontamination or detoxification of PHOs; moreover, they have\r\nbeen shown to be resistant to extensive processing, including cooking. Australia and New\r\nZealand are the only countries that included PHOs in their mycotoxin regulations, with a limit\r\nof 5 μg/kg in lupin seeds and derived products.\r\nPhomopsins are poorly studied mycotoxins and risk assessment on PHOs has not been done at\r\nthe European level. The collection of all available scientific data was requested by EFSA in a\r\nspecific project and partners involved considered it of general interest preparing this review to\r\nhighlight the limited available information, which indicate that the assessment of potential\r\nrisk related to PHOs is currently not feasible.