Study On The Control Of Dengue Vector Aedes By RNAi Engineering Microalgae

Vector-borne diseases,represented by dengue fever,have become a very important and urgent worldwide public health problem.According to statistics,about half of the world's people are at risk of contracting such diseases every year.Aedes albopictus is the main medium for the transmission of dengue fever.Dengue has four major serotypes.Since,there is no effective vaccine to prevent infection,it is crucial to prevent the spread of dengue fever by cutting off transmission routes.Today,mainly through physical methods and chemical methods to eliminate vector mosquitoes,but the environment will cause irreversible pollution,the target species will also cause a certain degree of damage,and gradually increase the resistance of mosquitoes.Therefore,an effective biological strategy to prevent and control the spread of mosquito-borne diseases is urgently needed in an environmentally friendly and ecologically sustainable way.As a reverse genetic tool,RNAi can knock off the target gene to realize the negative regulatory function of gene expression.HR3(hormone receptor 3)plays an important role in the development of insect reproduction,participates in the maturation of oocytes and the spawning process of female Aedes albopictus,and regulates the formation of molting and insect pupae,if knockout,it will cause the insects to not shedding their skin normally and the larvae quickly die.Hydroxy dog Urea(3-HK)is a highly active intermediate in Aedes albopictus,which can easily to oxidize and produce a large number of reactive oxy-gen species,resulting in the death of Aedes albopictus.3HKT(3-hydroxykynurenine transaminase)catalyzed 3-hk into the yellow urine acid,blocking the active oxygen generation pathway,which is beneficial to the normal growth and development of Aedes albopictus.Objective: The genes encoding the two proteins HR3 and 3HKT are used as RNAi target genes.After expression,the larvae of Aedes albopictus was fed to the HR3 and 3HKT genes in the larvae of Aedes albopictus,and the expression level were reduced,so as to determine the lethal effect of engineering algae strains on Aedes albopictus,and lay the foundation for the biological Anti-Mosquito To achieve biological control of dengue fever.Methods: The HR3 and 3HKT two genes of Aedes albopictus were cloned,and the expression vectors of RNAi were constructed to convert them into CC425 algae strains in the Rhine and feed the larvae of Aedes albopictus.The mosquito larvae of Aedes albopictus were tested by biological detection,cell tissue observation,and RNA level,and the effect of transgenic algae strains on mosquitoes was determined.Results: In biological observation,larvae fed HR3 and 3HKT transgenic algae showed a significantly slowly growing than the control group larvae.The larvae fed the transgenic algae were killed in the 20 th hour,and the larvae fed the 3HKT transgenic algae were more rapidly killed than the larvae fed HR3 transgenic algae strains.Pathological Tissue section observation,the larvae feeding transgenic algae in the epidermis,the middle intestine and other areas have been different degrees of destruction.At the level of RNA,the target gene expression levels of the larvae fed genetically modified algae were decreased in different degrees.Conclusions: RNA interference happened in the larvae of RNAi transgenic algae could decrease the expression level of HR3 and 3HKT,and eventually hinder the growth and development of Aedes albopictus,resulting in the death of Aedes albopictus larvae.This research provides some technical ways and methods for bio-logical strategies to prevent and control mosquito-borne diseases and has contributed a new way for large-scale control of mosquito-borne disease.