Function Analysis Of E1 Effector From Fusarium Oxysporum

Fusarium oxysporum f.sp.cubense(Foc)are the agents of banana(Musa spp.)wilt disease(also named as ’panama disease’).These soil-borne fungi could infect banana root system and conolize in xylem,leading to the death of plants.It is helpful for controlling the disease to figure out the molecular mechanism of the virulence of the pathogens.In the present study,functions of the effector E1 in regulating virulence of Foc tropical race 4(Foc TR4)were investigated.1.The gene encoding a hypothetical effector protein was predicted and named as E1.E1 was only identified in the genome of Foc TR4 but not in Focl,suggesting that E1 might be involved in the virulence of Foc TR4 to Cavendish banana.2.Expression profile analysis revealed that E1 was highly induced during the infection process of Foc TR4 to Cavendish banana;and the expression level of E1 was extreamly low when Foc TR4 was cultured In vitro.The results suggested that E1 was involved in the biotrophic infection of Foc TR4.3.The knock-out and complementary mutants of E1 were constructed.The results showed that knocking out of E1 increased virulence of Foc TR4;While over-expression of E1 did not show obvious effect on virulence.4.Subcellualar localization analysis of E1-GFP suggested that E1 might be distributed in vesicles.5.Transient expression of E1 in leaves of Nicotiana tabacum did not induce the accumulation of reactive oxygen species,indicating that E1 was not a virulence protein.Our results showed that the effector E1 is involved in virulence of Foc TR4 to Cavendish banana.Further identification of the targets of E1 in host plant cells should be conducted to explain the mechanism of E1 in regulating virulence of Foc TR4.