The Mechanism Of Sex Determination Based On Cascade Interaction Between Transformer2 And Doublesex In Bemisia Tabaci

Sex determination of organism is not only the basic for gender formation and normal development,but also it could have important implication for the continuation of ethnic reproduction. Bemisia tabaci is a worldwide agricultural pest, and is haplo-diploid. The male from unfertilized egg is haploid and the female from fertilized egg is diploidy. To study the mechanism of sex determination in Bemisia tabaci,we cloned and analyzed transformer2(Bttra2) and doublesex(Btdsx) which were key genes in sex determination cascade, and further study the function of transformer2 and doublesex in Bemisia tabaci of sex determination by use of RNAi technology. The results showed that the full-length of Bttra2 and Btdsx were respectively 1702 bp and 2399 bp. Btdsx was consisted of seven exons and six introns and Bttra2 was consisted of 10 exons and 9 introns. There were four splice forms and four proteins of Bttra2 and and the expression abundance of Bttra2 in male was higher than that in female. There were 13 splice forms and six proteins of Btdsx and the expression abundance of Btdsx in male was higher than that in female. Btdsx and Bttra2 could be affected each other and have played a vital role in whitefly sex determination cascade. Silencing the Bttra2 would cause significantly down Btdsx expression and silencing the Btdsx would also cause significantly down Bttra2 expression. What’s more, Silencing the Bttra2 or Btdsx would influence Vg gene expression and caused male whiteflies genital malformations,missing the male end needle. The results clarify the mechanism of sex determination whitefly has important theoretical significance.