Trichothecene genotypes and chemotypes among species complex isolated in argentina during two wheat harvest seasons

YERKOVICH, N; SULYOK, M; PALAZZINI, J.M; CHULZE, S.N

Florianopolis

Congreso; 5th International Symposium on Fusarium Head Blight (ISFHB) and 2nd International Workshop on Wheat Blast (IWWB) Florianópolis, Brazil, 6 a 10 Abril de 2016.; 2016

Embrapa, CAPES

Members of the Fusarium graminearum species complex (FGSC) are the causal agents of Fusarium Head Blight (FHB) in wheat worldwide. The disease causes reductions in grain yield, quality and safety due to the contamination with trichothecenes, mainly deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-ADON), 3-acetyldeoxynivalenol (3-ADON) and nivalenol (NIV); and zearalenone (ZEA). Determination of chemotype is relevant in the analysis of Fusarium species populations that causes FHB. Shifts in trichothecene chemotypes have been observed in Europe, China and Canada, this aspect is of concern to strains aggressiveness and toxin production. In Argentina, 17 FHB outbreaks had occurred in the last 50 years with loses ranging from 30% to 70%. The aim of the present study was: -to characterize trichothecene genotype and chemotype of two populations of F. graminearum collected from wheat grains in Argentina during an epidemic and a non-epidemic year. A total of 229 F. graminearum isolates were collected from the wheat growing Zone II North during 2012 and 2014 harvest season. PCR assays were carried out to predict DON, 15-ADON, 3-ADON and NIV genotype. Chemotypes were determined by LC-MS/MS. From the total isolates evaluated in 2012 harvest season, 110 isolates belong to 15-ADON genotype and 3 isolates were NIV genotype. Among the isolates from 2014 harvest season, 103 belong to 15-ADON genotype and 4 were NIV genotype. The isolates collected from 2012 harvest season were all DON producers (mean 8,63 mg/kg), 84 were 15-ADON producers (mean 2,17 mg/kg), 22 were 3-ADON producers (mean 0,47 mg/kg), 1 isolates was NIV producer (0,1 mg/kg) and 116 isolates were ZEA producers (mean of 2,11 mg/kg). All the isolates collected from 2014 harvest season were DON producers (mean 9,77 mg/kg), 65 were 15-ADON producers (mean 0,85 mg/kg), 47 were 3-ADON producers (mean 2,83 mg/kg) and 2 were NIV producers (mean 0,10 mg/kg) and 114 isolates were ZEA producers (mean 15,3 mg/kg. The chemotype profiles observed in this study; showed the potential of the species within the FGSC to produce a wide range of Type B trichothecenes and high levels of zearalenone. It is important to indicate the difference in chemotype between the isolates from the two harvest seasons evaluated. In the actual condition of climate change it is relevant the evaluation of the toxin ability of the fungal populations for the implication on food safety.