| The diamondback moth（DBM）,Plutella xylostella（L.）（Lepidoptera:Plutellidae）is the most destructive pest of cruciferous vegetables throughout the world.Because of its high fecundity,short life cycle,and rapid resistance evolution to any conventional insecticides,new control measures are urgently needed.Nowadays,strategies targeting at adult stages have sound application potentialities in DBM control for the high control efficiency,safety to the environment and natural enemies,and high economic benefits.Application of sex pheromone products plays an important role in adult control strategies.However,since its biosynthesis and composition might vary with differing internal and external factors,the application efficiency is often unstable.Therefore,investigating the effects of various internal and external factors on genes involved in sex pheromone biosynthesis and reception pathway of DBM and then finding out the regulation measures of key involved genes shall help to overcome this.Based on this,in this thesis,the expression dynamics of genes involved in sex pheromone biosynthesis and reception pathway in DBM was studied,and the effects of nutritional conditions,mating,pyripropoxyfen（a juvenile hormone analogue）,precocene II（a juvenile hormone inhibitor）on the expression of the involved genes were investigated.The results indicated that the expression of alcohol dehydrogenase 9（AD9）,acetyl CoA carboxylase 3（ACC3）,acetyl CoA carboxylase 4（ACC4）,acetyl CoA carboxylase 5（ACC5）,PBANR-C genes was comparatively higher,but that the expression levels ofΔ166 desaturase（DES16）,acetyltransferases 7（ACT7）,fatty acyl reductase 6（FAR6）,Δ12desaturase（DES12）,fatty acyl reductase 5（FAR5）and PBANR-B was lower.Most genes were expressed rhythmically,e.g.,expression of DES16,DES12,ACT7,FAR5,AD9 and ACC3,ACC4,ACC5 peaked at12h or 24h after adult emergence and then decreased.Meanwhile,FAR6,PBANR-B and PBANR-C genes were highly expressed throughout the experiment with no obvious peaks.Compared with water containing 10%honey,water feeding increased the expression of ACT7,FAR6 and DES12,but did not change that of DES16,FAR5,AD9,ACC3,ACC4,ACC5,PBANR-B and PBANR-C genes.After 24h of starvation,the expression of DES16,FAR5,ACC3 genes was decreased,but that of ACT7、FAR6、DES12、AD9、ACC4、ACC5、PBANR-B、PBANR-C remained unchanged.After mating,the expression of DES16,FAR5,AD9,ACC3,ACC4,ACC5,PBANR-B,PBANR-C genes was kept unchanged.However,that of ACT7 and DES12 genes was increased and FAR6 was decreased.After 24 hours of treatment with pyripropoxyfen,the expression of DES16,ACT7,DES12,AD9 and PBANR-B was increased,FAR6 was decreased,but that of FAR5,ACC3,ACC4,ACC5 and PBANR-C remained unchanged.On the contrary,precocene II treatment decreased the expression DES16,ACT7,FAR6,DES12,FAR5 and ACC3,but did not change that of of ACC4,ACC5,PBANR-B and PBANR-C.Pyripropoxyfen and precocene II,mating,starvation and water feeding all have different effects on sex pheromone synthesis and reception pathway genes in Plutella xylostella（L.）,but the mechanism remains to be further studied. |
