Integrated management of wheat aphid and BYDV by protein elicitor

Sitobion avenae is one of the destructive aphids on wheat, causing huge loss in agriculture by plant sap consumption and virus transmission including barley yellow dwarf virus (BYDV). The wheat - aphid - BYDV composes the plant - vector - virus system with wheat aphid as the control target. Nowadays, induced plant defense is a hot topic as an alternative of neurotoxic pesticides. Protein elicitor is a kind of inducer of plant defense response.In this study, PeaT1 and Hrip1, the two main components of commercial pesticide Atailing, were investigated on wheat to assess the control efficiency on S. avenae and BYDV.
Firstly, intrinsic rates of aphid increase declined in PeaT1 treatment compared with control plants. S. avenae preferred to colonize control than PeaT1 treated wheat seedlings in host selection test. PeaT1 treated wheat leaves possessed more trichomes and cuticular wax that formed a disadvantageous surface environment for S. avenae. Both salicylic acid (SA) and jasmonic acid (JA) were significantly accumulated in PeaT1 treated wheat seedlings. The intrinsic rates of aphid increase were also reduced on Hrip1 treated wheat plants corresponding to higher trichome densities and cuticular wax deposition on wheat leaves. Photosynthesis related chlorophyll and soluble sugars, defense related total phenol and lignin, and phytohormones SA and JA were all significantly accumulated. SA and JA pathway related genes were also up regulated. Secondly, control efficiencies on BYDV disease were 35% in PeaT1 treated wheat seedlings, and from 30 to 50% in Hrip1 treated wheat seedlings. PeaT1 and Hrip1 treated wheat seedlings decreased virus transmission efficiency by prolonging time for aphid to find probing and feeding site. Additionally, PeaT1 and Hrip1 weakened the symptom of dwarf and yellow in wheat seedlings caused by BYDV.
In conclusion, both PeaT1 and Hrip1 triggered SA and JA pathways to regulate the defense response in wheat. The surface structure and metabolites of wheat were significantly modified by protein elicitors to reduce reproduction and deter colonization of S. avenae. The two protein elicitors inhibited transmission and proliferation of BYDV. Additionally, they promoted wheat growth to reduce biomass loss caused by wheat aphid and BYDV. Both PeaT1 and Hrip1 are prospective to be applied in integrated management of wheat aphid and BYDV in the fields.