The Research On Mating Ability Of Male Age And Cloning And Expression Of The Sex Gene Transformer-2 In Bradysia Odoriphaga

The larva of Bradysia odoriphaga Yang et Zhang,commonly known as the leek maggot,is a unique underground vegetable pest in China,mainly distributed in Hebei,Shandong,Tianjin,Liaoning,Gansu and other northern Chinese cities.The leek maggot can harm 7 families more than 30 plants,especially like eating leeks,Onions,garlic and other lily vegetables.Below the circumstance that does not take any control measure,leek maggot can bring about leek to reduce production by 50% left and right sides,destroy even when serious kind or close out.At present,the research on B.odoriphaga mainly focuses on biology and prevention and control.However,a good control effect needs to be established on the basis of early prevention,early detection and early prevention and control of B.odoriphaga.It is helpful to improve the sex pheromone monitoring level if the mating ability of B.odoriphaga can be clearly defined.In addition,the offspring of the female adult of B.odoriphaga have obvious sex deviation phenomenon such as all-female or all-male.It would be helpful to elucidate the mechanism of determining the sex of the offspring of B.odoriphaga.For the above two purposes,this paper research under different day age B.odoriphaga of male mating ability and its influence on female fertility under the conditions of temperature 25?,humidity 70±5% and photoperiod L:D=14:10.At the same time,it has been reported that transformer-2(tra-2)gene may be involved in sex determination in other insects.In this paper,the tra-2 gene was cloned,and the biological information and transcriptional levels under different developmental stages and temperature stress were analyzed.The research results are as follows:(1)The effects of the age of male B.odoriphaga on their mating ability and female reproductive ability were determined.In the absence of mating,there was no significant difference in the average life span between male and female adults of B.odoriphaga(4.5 d for male and 4.2 d for female).Males can mate up to 13 times in their lifetime,and the number of mating with females decreases with the increase of male's age.With the increase of the number of mating between males,the mating time with females was prolonged,up to 97 min.However,the number of mating between males was correlated with the number of eggs and the hatching rate of females.Especially,when the number of mating between males exceeded 8 times,the number of eggs and hatching rate of females decreased significantly.(2)Cloning and expression of Biotra-2 gene sequence of B.odoriphaga.Conserve domain analysis showed that Biotra-2 gene contained a conserved region of tra-2 gene,RRM-TRA2.By phylogenetic tree analysis that the Biotra-2 and Bradysia coprophila tra-2 genes were found to be clustered into a single strand.Then it got together with sciara ocellaris tra-2 gene.And Biotra-2 has the farthest relationship with Aedes aegypti and Drosophila melanogaster tra-2 genes.Biotra-2 gene has no sex-specificity in B.odoriphaga.(3)The transcriptional level of Biotra-2 gene transcriptional levels under different developmental stages and temperature stress were analyzed.Biotra-2 gene was expressed differently in different developmental stages of B.odoriphaga.With the passage of the egg phase,the expression level of tra-2 gene in the egg decreased.As the temperature increases,tra-2 gene expression decreased in eggs,20? expression of the highest in the production of eggs,25 to 30? to very significantly reduce the amount of expressed in eggs.Biotra-2 gene expression was not significantly different between male and female individuals in egg stage,1st larva stage,but significantly different between male and female individuals in larva stage 2-3 and pupa stage,There was a very significant difference in expression level between male and female individuals in 4th larva and adult stage.Overall,the expression abundance of tra-2 gene was the lowest in the late stage of female larvae and the highest in female adults.This research elucidated the reproductive behavior characteristics of B.odoriphaga,and the biological information and transcriptional levels under different developmental stages and temperature stress were analyzed.It provides theoretical reference data for explaining the outbreak mechanism and applying its sex pheromone.