Molecular characterization of Fusarium subglutinans associated with mango malformation

Mango malformation is a serious disease of Mangifera indica in tropical and subtropical regions of the world. This disease is caused by Fusarium subglutinans, which is also associated with diseases on many other hosts, such as pineapple, pine, maize and sugarcane. The F. subglutinans strains associated with different hosts are virtually indistinguishable using morphological characters, but can be easily differentiated using histone and beta-tubulin gene sequencing, and some have subsequently been assigned to distinct species. The aim of this study was to characterize F. subglutinans isolates associated with mango malformation using histone H3 gene sequencing and to compare them with other isolates in the Gibberella fujikuroi complex. Analysis of histone sequence data revealed the presence of two phylogenetically distinct groups of F. subglutinans isolates associated with mango malformation. We also considered the identity of the two groups of isolates associated with mango malformation and determined their relatedness to other Fusarium spp. For this purpose, portions of the beta-tubulin gene were sequenced and compared with the beta-tubulin sequences deposited in the National Center for Biotechnology Information (NCBI) nucleotide database. This comparison to the NCBI database indicated that one group of F. subglutinans strains isolated from mango constitutes a unique lineage in the G. fujikuroi complex. Based on beta-tubulin and histone H3 sequencing, the second group of isolates is conspecific with the F. subglutinans strains previously reported to be the causal agent of mango malformation.