Effects Of Cucurbitacin B And EGCG On The Host Biotypes Of Cotton Aphid

The cotton aphid,Aphis gossypii Glover,is a worldwide pest.Due to its polyphagous characteristics,cotton aphid has formed different host biotypes in the process of long-term evolution with different plants.Now,the secondary metabolism of compounds in plant has critical influence on insect host isolation.Cucurbitacin B and EGCG are typical secondary metabolites of two host biotypes of cotton aphid's host plant.In this paper,we study.the effects of Cucurbitacin B and EGCG on growth and detoxification enzymes of two different host biotypes of cotton aphid.The role of Cucurbitacin B and EGCG in the formation of two host biotypes of cotton aphid and two secondary metabolites as control cotton aphid possible candidate were discussed.1.Through the establishment of the life table of cotton aphid population method,found that cotton and cucumber-specialized aphid's offspring survival rate and survival days were significantly lower than the control group,net reproductive rate R₀,mean generation time T are less than the control group when the cotton aphid eating the host plant leaves after treatment of Cucurbitacin B.It's suggested that Cucurbitacin B has a certain inhibition effect on the growth and development of two host biotypes cotton aphids,and it is expected to be developed as a new pesticide to contribute to the green control of cotton aphid.Through the establishment of the cotton aphid host transfer life table method,found that cotton and cucumber-specialized aphid's offspring first generation,second generation and third generation of mean generation time T,net reproduction rateR₀,intrinsic rate r_m have no significant difference compared with control.The result showed that Cucurbitacin B could not improve the suitability of cotton and cucumber specialized aphid for non-host plants.2.Through the establishment of the life table of cotton aphid population method,found that cotton and cucumber-specialized aphid's offspring survival rate and survival days were significantly lower than the control group,net reproductive rate R₀ are less than the control group when the cotton aphid eating the host plant leaves after treatment of EGCG.It indicate that EGCG has a inhibition effect on the growth and development of two host biotypes of cotton aphid,and is expected to develop new green pesticides to provide new ideas for the synthesis of new insecticides.Through the establishment of the cotton aphid host transfer life table method,we found that the treatment group cotton-specialized aphid's offspring first generation net reproductive rate R₀,mean generation time T were significantly higher than control group.but intrinsic rate r_m have no significant difference compared with control.The treatment group of offspring second generation and third generation's net reproductive rate R₀,intrinsic rate r_m were dramatically lower than control group.The treatment group cucumber-specialized aphid's offspring first generation,second generation and third generation of mean generation time T,net reproduction rateR₀,intrinsic rate r_m were dramatically higher than control.In sum,EGCG stably improve the suitability of cotton and cucumber specialized aphid for non-host plants.Therefore,EGCG may be a substance that influences the formation of cotton and cucumber specialized aphid.3.Analyzing the influence of Cucurbitacin B and EGCG to the activity of Car E,GSTs,ACP,Ach E and CYP450 in Aphis gossypii,when the cotton and cucumber-specialized aphid feeding the host plant leaves after treatment of Cucurbitacin B and EGCG.The result revealed that the activity of GSTs,ACP,Ach E in cotton and cucumber-specialized aphid were gradually increased with the extension of Cucurbitacin B feeding time,when the time was 72h,the activity of enzymes was the highest.However the activity of Car E was gradually decreased,when the time was72h,the activity of enzymes was the lowest.The activity of CYP450 was decreased and then increased.As the extension of feeding time of EGCG,the activity of GSTs,ACP,Ach E,Car E in cotton and cucumber-specialized aphid were gradually increased,when the time was 72h,the activity of enzymes was the highest.The activity of CYP450 was decreased and then increased.