Physiological, genetic and transcriptional characterization of Fusarium graminearum isolates

Abstract

Fusarium graminearum is the primary cause of Fusarium head blight (FHB) epidemics worldwide. Thecharacterization of F. graminearum isolates via physiological, genetic, and transcriptional analysis was aimed in thestudy. A total of 31 isolates and a reference strain were grown on potato dextrose agar (PDA) for 7 days. According tomeasurements on the 4th and 7th day of cultivation, their minimum and maximum mean linear growth rates (LGRs)were calculated as 9.62±0.44 to 13.32±0.69 mm/day, respectively. Isolates were grouped as x<10 mm/day and10<x<20 mm/day. Amplification products of the internal transcribed spacer (ITS) regions of ribosomal RNA (rRNA)coding sequences with 1147 bp were digested with three restriction endonucleases in all isolates. Two differentrestriction profiles were obtained with PstI and Eco31I digestions whereas EcoRI yielded single banding profile.Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping was able to distinguishisolates within the same species under four groups. FgMgv1, tri4 and MAT1-1-2 gene expression levels of selected oneeach isolate (FgM1, Fg174 and Fgsh4) with the highest, moderate and the lowest LGRs (13.32±0.69, 11.32±0.15 and9.62±0.44 mm/day, respectively) were examined by qRT-PCR. Relative mRNA abundance values of FgMgv1 were1.715±0.199, 0.089±3.166e-004 and 0.020±1.408e-004 for FgM1, Fg174 and Fgsh4, respectively. Similarly, thesevalues for tri4 were calculated as 0.081±0.009, 0.016±0.004 and 0.002±4.338e-005 and for MAT1-2 as 2.097±0.484,1.901±0.195, 1.047±0.136. Expression levels of these genes were significantly higher in FgM1 with the highest LGRvalues. Outcomes showed that PCR-RFLP method may become possible to distinguish the members of Fusariumspecies complex more clearly. Moreover, determined correlation among the LGRs of isolates, their aggressiveness andmycotoxin production capacities provided basic knowledge for supporting studies intended to control FHB infections