Studies on the Fusarium graminearum complex affecting wheat in Southern Brazil suggest a phylogenetic species-specific B-trichothecene profile.

ASTOLFI P.; SCHNEIDER L. ; SIMON LL; DEL PONTE EM,; ALVES TCA, ; TESSMANN DJ,; REYNOSO MM; RAMIREZ ML, ; TORRES AM,; FARNOCHI C, ; CHULZE SN.

Orlando, Florida

Otro; 2009 National Fusarium Head Blight Forum; 2009

U.S Wheat & Barley Scab Iniciative

Several members within the Fusarium graminearum species complex (Fg complex) have been reported in association with some host crops in Brazil. Our previous studies on a set of wheat isolates from regional populations have revealed the predominance of lineage 7 (F. graminearum sensu stricto) possessing a consistent 15ADON trichothecene genotype, whereas a small proportion of isolates belonged to lineage 2 (F. meridionale) and presented a nivalenol (NIV) genotype. We advanced our studies on three local populations of strains isolated from wheat, to test our hypothesis that multiple phylogenetic species are present and may have a species-specifi c B-trichothecene profi le. A sample of 55 strains were obtained from symptomatic kernels collected at Cruz Alta (n=19) Ernestina (n=19) and Nonoai (n=17) municipalities during 2007 growing season. We used AFLP markers to determine the similarity among the isolates of Brazilian populations with members of the Fg complex. A total of 150 AFLP bands were identified in the 200–500 bp range when using three primer pair combinations (EcoRI-AA/MseI-AT,EcoRI-CC/ seI-CG, EcoRI-TG/MseI-TT). Representatives of members of Fg complex (lineages 1 to 9) were included in the study to compare with our isolates. A multiplex PCR was used to determine the trichothecene genotypes with sequence primers targeting portions of Tri3 and Tri12 genes that are predictive of 15ADON, 3ADON and NIV chemotypes. Our results confi rms the predominance of the 15-ADON genotypes (48/55) all grouping with lineage 7. The NIV genotype was also found (06/55) and, in agreement with our previous fi ndings, most belonged to lineage 2. However, one NIV isolated grouped with lineage 5 (F. acaciae-mearnsii). The only 3-ADON, detected in Ernestina population, grouped with lineage 8 (F. cortaderiae). In spite of the relative low number of strains analyzed this far, we confi rm that FHB in Brazil is caused by multiple phylogenetic species and suggest a species specifi c B-trichothecene profi le, especially for the predominant species (F. graminearum sensu stricto).Fusarium graminearum species complex (Fg complex) have been reported in association with some host crops in Brazil. Our previous studies on a set of wheat isolates from regional populations have revealed the predominance of lineage 7 (F. graminearum sensu stricto) possessing a consistent 15ADON trichothecene genotype, whereas a small proportion of isolates belonged to lineage 2 (F. meridionale) and presented a nivalenol (NIV) genotype. We advanced our studies on three local populations of strains isolated from wheat, to test our hypothesis that multiple phylogenetic species are present and may have a species-specifi c B-trichothecene profi le. A sample of 55 strains were obtained from symptomatic kernels collected at Cruz Alta (n=19) Ernestina (n=19) and Nonoai (n=17) municipalities during 2007 growing season. We used AFLP markers to determine the similarity among the isolates of Brazilian populations with members of the Fg complex. A total of 150 AFLP bands were identified in the 200–500 bp range when using three primer pair combinations (EcoRI-AA/MseI-AT,EcoRI-CC/ seI-CG, EcoRI-TG/MseI-TT). Representatives of members of Fg complex (lineages 1 to 9) were included in the study to compare with our isolates. A multiplex PCR was used to determine the trichothecene genotypes with sequence primers targeting portions of Tri3 and Tri12 genes that are predictive of 15ADON, 3ADON and NIV chemotypes. Our results confi rms the predominance of the 15-ADON genotypes (48/55) all grouping with lineage 7. The NIV genotype was also found (06/55) and, in agreement with our previous fi ndings, most belonged to lineage 2. However, one NIV isolated grouped with lineage 5 (F. acaciae-mearnsii). The only 3-ADON, detected in Ernestina population, grouped with lineage 8 (F. cortaderiae). In spite of the relative low number of strains analyzed this far, we confi rm that FHB in Brazil is caused by multiple phylogenetic species and suggest a species specifi c B-trichothecene profi le, especially for the predominant species (F. graminearum sensu stricto).