Mitogenome targeted phylogenetic analysis in Fusarium head blight pathogens

Fusarium head blight (FHB) is one of the most devastating diseases of cereals worldwide. Genomic plasticity and the relatively high level of polymorphisms in chromosomal and mitochondrial genomes (mitogenome, "mtDNA") of FHB pathogens are important reasons for failure to control FHB. In this study, mtDNA genome based phylogenetic analysis were carried out in causal agents of FHB with totally 20 accessions (Fusarium graminearum with 15 members, F. culmorum, F. avenaceum, F. pseudograminearum, F. poae, F. proliferatum, and F. solani-F. oxysporum as outer groups). Nucleotide sequences of mtDNA were obtained from GenBank. Sequence similarity and UPGMA trees were constructed by MAFFT software. R/RStudio (with packages of "ape", "phangorn", and "factoextra") was used to obtain distance matrix, maximum likelihood (ML) dendrogram, and principal component (PCA) analysis-derived data of FHB pathogens. Bayesian topology analysis was carried out using MrBayes software via Ubuntu-Linux terminal. Individuals belonging to different species showed markedly different clustering via ML and UPGMA dendrograms which included F. graminearum members within the same sub-cluster. Distance matrix also supported this cluster profiling with mean distance value as 41.75%. In PCA analysis, FHB pathogens were clustered together in Dim1 and Dim2 whereas F. solani and F. oxysporum (not FHB pathogens) were clustered distinctly. Percentages of dimensions were as 93% and 6% for x and y axes meaning that FHB causal agents were genetically so similar for their mtDNA phylogeny. Bayesian topology analysis showed that members of F. graminearum and remaining FHB pathogens were genetically dissimilar with F. solani and F. oxysporum. It was found that mitogenome can strongly differentiate Fusarium spp. not only at the species-specific level, but also in terms of pathogen characteristics. Specific and potential marker genes located in mtDNA of FHB pathogens can also be investigated in future studies for detailed characterization of FHB pathogens.