Identification of a class of CFEM proteins containing a new conserved motif in Fusarium oxysporum

Abstract

Fusarium oxysporum (Fo) is an important soil-borne fungus that cause huge economic losses worldwide. Fungal-specific Common in Fungal Extracellular Membrane (CFEM) proteins are known to be involved in some important physiological processes associated with pathogenicity. To date, few Fo CFEM proteins have been characterized. The recent publication of several genomes of Fo has allowed us to conduct a genome-wide comparison analysis of CFEM proteins in Fo. In this study, we identified CFEM proteins for 12 different Fo formae speciales(f. sp) and obtained an average of 16 CFEM proteins for each Fo. The Fo CFEM proteins were classified into three groups (groups 1–3) according to structural features. Importantly, we identified a new conserved motif containing about 50 amino acids (DR motif) in group 1 members. CFEM proteins containing DR motif (CFEM_DR proteins) are remarkably conserved among Fo, and their number is greater in Fo compared with other fungi. We found the expansion of CFEM_DR proteins in Fo can be attributed to the segmental duplications in the genomes. Expression analysis revealed that CFEM_DR genes had a higher expression level in mycelium than conidia, and their expressions increased dramatically in the host roots at 3 days post inoculation, indicating that Fo CFEM_DR genes have roles while colonizing and infecting their hosts.