The F-box protein encoding genes of the leaf-rust fungi Puccinia triticina: Genome-wide identification, characterization and expression dynamics during pathogenesis

Abstract

Abstract Aim - This study was aimed at identifying F-box genes in Puccinia triticina, the causal organism for the leaf rust disease in wheat and inferring their role in pathogenicity in susceptible wheat plants. Methods and results - Genome-wide analysis revealed 10 F-box genes and were characterized using in silico approaches for revealing phylogenetic relationships, gene structures, gene ontology, protein properties, sequence analysis and gene expression studies. Domain analysis predicted functional domains like WD40 and LRR at C-terminus along with the obvious presence of F-box motif in N-terminal. MSA showed amino acid replacements, which might be due to nucleotide substitution during replication. Phylogenetic analysis revealed the F-box proteins with similar domains to be clustered together while some were spread out in different clades, might be due to functional diversity. The clustering of GG705409 and TaAFB4/TaAFB5 in a single clade suggested the possibilities of horizontal gene transfer during the coevolution between Pucciniaand wheat. Gene ontological annotation categorized them into three classes and were functionally involved in protein degradation through the protein ubiquitination pathway. Protein-protein interaction network revealed F-box proteins to interact with other components of SCF complex involved in protein ubiquitination. Relative expression analysis of five F-box genes in a time course experiment denoted their role in pathogenicity in leaf rust susceptible wheat plants. Conclusion- This study provides information on structure elucidation of F-box proteins of a basidiomycetes plant pathogenic fungi and their role during pathogenesis. A total of 10 F-box genes were predicted in Puccinia triticina genome sequences that revealed conserved phylogenetic relationship among different Pucciniaspecies. Expression analysis imparted their role in pathogenicity.