Abstract: Total RNA were isolated from salivary gland dissected from partially engorged Boophilus microplus. The mRNA was purified. A library of oligo(dT)-primed cDNA with added directional EcoR I/HindⅢ linkers was constructed from the purified mRNA. The constructed cDNA was ligated to the EcoR I/HindⅢarms of the λSCREEN vector. The recombinant phage DNA was packaged by phage-marker packaging extracts，resulting in a primary cDNA library with a size of 1.38×10⁶ PFU. Data showed 100% of the library were recombinant and the titer of the amplified library was 2×10⁹ PFU/ml. A partial cDNA encoding cytochrome oxidase C subunit II of B. microplus was screened from the expression library with rabbit serum against B. microplus salivary gland proteins. The results is suggested that the cDNA expression library has been constructed.

Key words: Boophilus microplus, cDNA expression library, Construction