Function Research Of CP Effector Of Fusarium Oxysporum F.sp.Cubense

Banana wilt disease is destructive to banana yield and widespread all over the world.Fusarium oxysporum f.sp.cubense Tropical Race 4(Foc TR4)in the main causal agent of banana wilt diseas.Effectors play important roles in the regulation of pathogenicity of fungal pathogens.Thus,investigation of Foc TR4 effectors could help build up fundamentals for controlling banana wilt disease.In the previous work,we have identified a series of effector candidates of Foc TR4.In the present study,5 candidates were selected for further investigation of their biological functions.The results showed that 2 proteins which contain conserved Cerato-platanin(CP)motif are required for pathogenicity of Foc TR4.Then the mechanism of the two CP proteins in the regulation of pathogencity were investigated.1.The bioinformatic analysis revealed that the two CP proteins are conserved in amino acid sequence with other fungal CP1 proteins.Thus,the two proteins were named as Foc CP1 a and Foc CP1 b,respectively.2.The single gene knock out mutants of Foc CP1 a or Foc CP1 b,and the combined mutant of both Foc CP1 a and Foc CP1 b were constructed.The phenotype analysis showed that knock-out of either Foc CP1 a or Foc CP1 b did not impair the pathogenicity of Foc TR4,whereas knock-out of both genes significantly decreased pathogenicity of the pathogen to banana plants.The results suggested that there is an redundancy in biological functions of Foc CP1 a and Foc CP1b;and the Foc CP1 proteins are required for virulence of Foc TR4 to banana.3.Subcellular localization analysis using tobacco leaves revealed that the two Foc CP1 proteins mainly distributes in both cytoplasm and nucleus.4.Through yeast two hybrid and Bi FC analysis,we found that Foc CP1 a and Foc CP1 b could both interact with Ma PR1 proteins of banana,the well-known disease resistant proteins in plants,suggesting that Foc CP1 might facilitate the infenction and colonization of Foc TR4 through inhibiting plant immunityOur findings have expounded the mechanism of Foc CP1 proteins in the regulation of pathogenicity of Foc TR4 and put fundamentals for development of disease control strategy.