|Del Ponte, E|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/16/2013
Publication Date: 5/16/2013
Citation: Del Ponte, E.M., Ward, T.J., Tessman, D.J., Kuhnem, P.R., Silva, C.N., Gomes, L.B., Spolti, P., Nicoli, C.P. 2013. Analysis of the Fusarium graminearum species complex in Brazil shows high diversity and changes in species prevalence affected by host and geographic region. Meeting Abstract. Interpretive Summary:
Technical Abstract: Previous studies have shown that Fusarium graminearum with the 15-acetyl deoxynivalenol (15-ADON) genotype was the main cause of head blight in wheat and barley in Brazil, followed by F. meridionale with the nivalenol (NIV) genotype. In this work, we expanded our understanding of F. graminearum species complex (FGSC) diversity in central and southern Brazil based on the analysis of a large number (n=1050) of isolates distributed in four new populations that were obtained between 2009 and 2011 from: 1) diseased heads from >150 wheat fields (n= 663 strains); 2) maize kernels from fields at both central and southern regions (n=104); 3) maize stubble showing perithecia obtained from 20 cultivated and non-cultivated fields (n=271); and 4) rice kernels from fields in the southern growing-region (n=12). Multilocus genotyping (MLGT) was used to determine species identity and trichothecene genotypes for most isolates. For those from maize kernels, partial gene sequences of TEF, tri3 and tri12 were used. For the wheat population, it was found that F. graminearum with a 15-ADON genotype was dominant (83%), followed by F. meridionale with a NIV genotype (12.8%), F. cortaderiae with mostly NIV and a few 3-acetyl deoxynivalenol (3-ADON) (2.6%), F. austroamericanum with mostly 3-ADON and a few NIV (1.2%) and F. asiaticum with the NIV genotype (0.4%). Frequency of F. meridionale was higher for the lower latitudes (Paraná State) and an atypical isolate with the 15-ADON genotype was found. For the maize kernel population, F. meridionale was dominant (72%), followed by F. graminearum with the 15-ADON genotype (14.5%) and F. cortaderiae with the 3-ADON and NIV genotypes (13.5%). For the maize stubble population, F. meridionale was dominant (50%), followed by F. graminearum with the 15-ADON genotype (30%) and F. cortaderiae with the NIV and 3-ADON genotypes (20%). For both maize populations, higher diversity was found at higher latitude and elevation. Finally, F. asiaticum with the NIV genotype was the sole species found in rice kernels. These results show that several species coexist in the subtropical to tropical agricultural regions of Brazil where species composition is shaped by both host and climate.