An Salivary Protein Mp1 In Myzus Persicae Can Promote Virulence By Interact With AtPP2-A1

Plants always can produce various defense mechanisms when attacked by pests.Among the various defense mechanisms,phloem-based defense(PBD)is mainly targeted at insects with piercing-sucking mouthparts,which represent a special mechanism of plants-insects interaction.PBD includes two major components,one is a comlex formed by the phloem protein(PP),another one is callose synthesized by β-1,3-glucan-like(GSL).Previous studies on PP2 in Arabidopsis in our laboratory have showed that PP2 is an induced gene with low expression level under normal plant growth conditions.When plants are attacked by pests or under environmental stress,the expression level is greatly improved,so the plant’s resistance to pests is strengthened.Arabidopis mutant PP2-A1 is more sensitive to green peach aphids(Myzus persicae)than the wild type(Columbia-0),while when PP2-A1 is overexpressed,it has an obvious inhibitory effect on aphid’s feeding and fecundity,indicating that PP2-A1 is the key gene in the PBD of Arabidopsis.In order to feed on phloem sap successfully,green peach aphids must develop a series of physical and chemical measures to cope with plant PBD.Green peach aphid(Myzus persicae)is a kind of typical insect that can penetrate the vascular bundle of plants to feed on phloem juice.Besides causing mechanical damage to plants,aphids can also transmit a variety of plant viruses.In order to feed and colonize successfully,green peach aphid needs to form a very close relationship with its host.In the detection and feeding of the needle,the aphid mainly secretes two types of saliva,namely gel-type saliva E1 and water-soluble saliva E2,E2 contains various enzymes,which can participate in inhibiting the plant defense reaction.Based on the known anti-aphids gene PP2-A1,the Pull-Down experiment was carried out with the peach aphid saliva to screen out the salivary protein Mp1 which may interact with PP2-A1,and then the bimolecular fluorescence complementation experiment(BiFC)and Co-Immunoprecipitation(Co-IP)further verified the interaction between PP2-A1 and Mp1.Then we explored the biological function of Mpl in Arabidopsis thaliana.The effect of Mpl on the localization of Mp1 was positively regulated by Mp1,which proved that Mpl can promote the invasion of Arabidopsis by regulating the PBD response of Arabidopsis thaliana.