J Appl Genetics (2012) 53:227–236 DOI 10.1007/s13353-012-0085-1 MICROBIAL GENETICS · ORIGINAL PAPER Polymorphism of mycotoxin biosynthetic genes among Fusarium equiseti isolates from Italy and Poland Łukasz Stępień & Karolina Gromadzka & Jerzy Chełkowski Received: 28 July 2011 / Revised: 10 January 2012 / Accepted: 25 January 2012 / Published online: 22 February 2012 # The Author(s) 2012. This article is published with open access at Springerlink.com Abstract Fusarium equiseti (Corda) Saccardo is a soil sap- rophyte and a weak pathogen, associated with several dis- eases of fruit and other crops in subtropical and tropical areas, but also in countries with temperate climate. A wide range of secondary metabolites has been identified among natural F. equiseti populations, with zearalenone (ZEA), fusarochromanone and fusarenon-X being the most com- mon. In present study, the genetic diversity of strains from two populations (from Italy and Poland) was evaluated by analysing the translation elongation factor 1α (tef-1α) sequences, two polyketide synthases from the ZEA biosyn- thetic pathway (PKS13 and PKS4) and the TRI5 gene from the trichothecene biosynthetic pathway. ZEA was produced in rice cultures by 20 of the 27 tested isolates in concen- trations ranging from 1.34 ng/g to 34,000 ng/g). The ability to produce enniatins and trichothecenes was evaluated in all strains by identifying esyn1, TRI13 and TRI4 genes. The presence of PKS4 and PKS13 genes was confirmed by polymerase chain reaction (PCR) in only some ZEA- producing isolates. Similarly, the TRI5 gene was found in 14 of the 27 isolates tested. This is likely to have been caused by the divergence of those genes between F. equiseti and F. graminearum (the latter species was used for the primers design) and can be exploited in phylogenetic stud- ies. The analysis of the mycotoxin biosynthetic gene Ł. Stępień (*) : J. Chełkowski Department of Metabolomics, Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland e-mail: lste@igr.poznan.pl K. Gromadzka Department of Chemistry, Poznań University of Life Sciences, Wojska Polskiego 75, 60-625 Poznań, Poland sequences can be used to differentiate the studied genotypes even more precisely than the analysis of the non-coding regions (like tef-1α). Keywords Biosynthetic genes . DNA polymorphism . Fusarium . Mycotoxins . Zearalenone . Phylogenetic markers Introduction Fusarium equiseti (Corda) Saccardo is a common soil sap- rophyte associated with several fruit and other plant tissue diseases of agriculturally important crops. The fungus is typical mostly for subtropical and tropical areas, but is also isolated from soil and plant hosts in countries of temperate climate zone, like Norway, Canada, Russia and Poland (Booth 1971; Kosiak et al. 2005; Marasas et al. 1984). The list of host species includes cereals (wheat, triticale, maize and rice), asparagus, cotton, potato, tomato, cowpea, onion and ginseng (Punja et al. 2008). Besides cultivated plants, it also colonises wild species, including herbal plants and trees, e.g. Equisetum L., Chenopodium L. and Pinus L. Although F. equiseti is considered as moderately aggressive, it is capable of synthesising a vast range of toxic secondary metabolites, which exhibit both phyto- and cytotoxicity (Langseth et al. 1998–1999; Morrison et al. 2002). These include the trichothecenes: 4-acetylnivalenol (fusarenon X, FUS-X), nivalenol (NIV), scirpentriol with its acetyl deriv- atives (MAS and DAS), and numerous other mycotoxins, such as zearalenone (ZEA), beauvericin (BEA), fusarochro- manone (FUSCHR), equisetine (EQ) and butenolide (Thrane 1989). Recently, ZEA became particularly interesting to the researchers because of its oestrogenic properties and the ability to be accumulated at high levels in naturally infected