Association of single nucleotide polymorphic sites in candidate genes with aggressiveness and deoxynivalenol production in Fusarium graminearum causing wheat head blight

Decay of LD was in most instances fast. Two neighboring SNPs in MetAP1 and one SNP in Erf2 were significantly (P < 0.05) associated with aggressiveness explaining proportions of genotypic variance (pG) of 25.6%, 0.5%, and 13.1%, respectively. One SNP in TRI1 was significantly associated with DON production (pG = 4.4).We argue that using the published sequence information of Fusarium graminearum as a template to amplify comparative sequence parts of candidate genes is an effective method to detect quantitative trait loci. Our findings underline the potential of candidate gene association mapping approaches to identify functional SNPs underlying aggressiveness and DON production for F. graminearum s.s populations.Fusarium head blight (FHB) is a destructive disease to cereals including wheat and barley. Fusarium graminearum (teleomorph Gibberella zeae) is considered to be the main causal agent of this disease in addition to other species such as F. culmorum [1]. F. graminearum complex has been subdivided into several cryptic species [2], the main member in Germany is F. graminearum sensu stricto (s.s.) [3]. FHB disease leads to prematurely bleached spikes in infected plants [1] with considerable yield losses and contamination by mycotoxins such as deoxynivalenol (DON) [4]. DON is the most common food and feed contaminant in Europe and the maximum permissible level in unprocessed wheat used for food is 1.25 mg kg-1 [5].The quantitative ability of an isolate to cause disease on a susceptible host plant in a non-race specific pathosystem is defined as aggressiveness [6]. Aggressiveness is an important factor determining the potential ability of an isolate to cause yield losses. Large genetic variation of aggressiveness, type of mycotoxin, and DON production was found among isolates sampled in the same country or even the same field [7-11]. The molecular causes of this tremendous variation in aggressiveness and DON production in F. graminearum are still unclear. To date, o