Production of zearalenone, deoxynivalenol, nivalenol, and acetylated derivatives by Australian isolates of Fusarium graminearum and F.pseudograminearum in relation to source and culturing conditions

Abstract

Australian isolates of Fusarium pseudograminearum (Fp = F. graminearum Group 1) and F. graminearum (Fg = F. graminearum Group 2) can produce mycotoxins including zearalenone (ZEA), 4-deoxynivalenol (DON), and nivalenol (NIV). Fp isolates from wheat and barley tillers in southern Queensland all produced ZEA and DON in culture, and one typical isolate also produced 3-acetyldeoxynivalenol. Most Fg isolates from wheat and sorghum grains in southern Queensland produced ZEA and DON and one typical isolate also produced 15-acetyldeoxynivalenol. Fg isolates from maize plants in northern Queensland were all ZEA and NIV producers, which was consistent with previous reports, and they also produced high concentrations of acetyl-nivalenols. ZEA and either DON or NIV production by cultures derived from different conidia (and ascospores in Fg isolates) varied by 4-18-fold for ZEA and 2-4-fold for DON/NIV production, and there were significant negative correlations between ZEA and either DON or NIV, indicating a common controlling process. The pattern of ZEA production was quite different between Fp and Fg, with ZEA production being relatively delayed in Fg. After 7 days incubation at 28°C on maize meal, one Fp isolate produced 49 mg ZEA/kg, but in both DON-producing and NIV-producing isolates of Fg, ZEA concentrations after 7 days were <1 mg/kg. ZEA and DON were produced on sorghum and combined wheat-barley grains as well as maize meal, although there were trends for maize meal to be more productive, probably due to greater surface area or different gaseous exchange. Low temperature incubation of a Fg DON-type isolate increased ZEA production, but did not affect either a Fg NIV-type isolate or a Fp isolate. Relationships between these patterns of mycotoxin production, pathogenicity, and implications for crop contamination are discussed.

Comparative Mycotoxin Profiles of Gibberella zeae Populations from Barley, Wheat, Potatoes, and Sugar Beets

“…Several researchers (18,19,38) have reported that isolates with the 3-ADON marker are dominant in warm regions and that isolates with the 15-ADON marker are found mainly in cool regions. The occurrence of different trichothecene-producing isolates of G. zeae reported here and in previous studies (2,7,18,22,34) may be due to the relatively wide range of environmental conditions under which the host crops are grown. In particular, temperature and precipitation (11,14) and substrate composition (31) were reported previously to be major factors influencing trichothecene production by G. zeae.…”

“…TRI3-and TRI12-based multiplex PCR assays were used to differentiate between G. zeae isolates associated with the 3-ADON marker and the 15-ADON marker. 2 analysis revealed a highly significant difference ( 2 ϭ 22.52; P Ͻ 0.0001) in the frequencies of genetic markers for 3-ADON and 15-ADON in G. zeae isolates from four crops. …”

The PKS4 Gene of Fusarium graminearum Is Essential for Zearalenone Production

“…ZON has several derivatives, such as ␣-zearalenol, that have greater estrogenic activity than ZON (47). ZON is produced by several Fusarium species, including F. graminearum, F. culmorum, F. cerealis (synonym, F. crookwellense), F. equiseti, F. semitectum (53), and F. pseudograminearum (5). There have also been reports of ZON production by other Fusarium species, but their accuracy has been questioned (53), as Fusarium taxonomy is complex and chemical analyses are not always clear-cut (29,51).…”

Management of mycotoxins in Australian maize

“…As explained above, this fungus is only common in Australia on the cool, wet tablelands of Far North Qld, where for reasons not completely clear, the fungus produces mainly NIV. In southern Qld and in NSW, the fungus produces mainly DON, also called vomitoxin (Blaney and Dodman 2002). It is very unusual for NIV and DON to exceed 1 mg/kg, a level reducing feed intake by pigs (Williams and Blaney 1994).…”

“…Tricothecenes known to contaminate maize include DON, also referred to as vomitoxin, and NIV (Blaney & Dodman 2002;Blaney, Moore & Tyler 1984;CAST 2003;JECFA 2012). The chemical structures of these toxins are illustrated in Figures 2-8 and 2-9.…”