Transcriptomic analysis of F. oxysporum Δcon7-1 mutant during in vitro growth

Previous studies have demonstrated the essential role of morphogenetic regulation in Fusarium oxysporum pathogenesis, including processes such as cell-wall biogenesis, cell division and differentiation of infection-like structures. We identified three F. oxysporum genes encoding predicted transcription factors showing significant identities to Magnaporthe oryzae Con7p, Con7-1, plus two identical copies of Con7-2. Targeted deletion of con7-1 produced non-pathogenic mutants with altered morphogenesis, including defects in cell wall structure, polar growth, hyphal branching and conidiation. By contrast, simultaneous inactivation of both con7-2 copies caused no detectable defects in the resulting mutants. Comparative microarray-based gene expression analysis indicated that Con7-1 modulates the expression of a large number of genes involved in different biological functions, including host-pathogen interactions, morphogenesis and development, signal perception and transduction, transcriptional regulation and primary and secondary metabolism. Taken together, our results points to Con7-1 as general regulator of morphogenesis and virulence in F. oxysporum. Con7-1 dependent gene expression in Fusarium oxysporum wt and Δcon7-1 mutant was measured after shifting the mycelia to PDB pH5.0 for 30 min and the transferred to PDB pH7.0 for 30 min. Three independent experiments were performed.