Quantitative RT-PCR
RNA was isolated from pooled adult (n = 3) and larval (n = 5)
honeybee samples using an RNeasy mini Kit (Qiagen, Germany)
following the manufacturer’s instructions. First-strand cDNA were
synthesized from 2 lg of total RNA using a SuperScript cDNA synthesis
III Kit (Invitrogen, CA) with dT primers according to the
manufacturer’s instructions. In order to evaluate the expression
of immune-related genes, the following primers were used. The sequence
of the Abaecin forward primer was (50-GGT AGT GAT ATT
TAT CTT CGC-30) and Abaecin reverse was (50-TTG AGG CCA TTT
AAT TTT CGG-30). The sequence of the Defensin1 forward primer
was (50-GTT GAG GAT GAA TTC GAG CC-30) and Defensin1 reverse
was (50-TTA ACC GAA ACG TTT GTC CC-30). The sequence for the
Hymenoptaecin forward primer was (50-ATA TCC CGA CTC GTT
TCC GA-30) and Hymenoptaecin reverse was (50-TCC CAA ACT
CGA ATC CTG CA-30). The sequence for the Rps5 forward primer
was (50-TTT CCC ATT ATT TCT ACC ATG CAT-30) and Rps5 reverse
was (50-CTT TAC AAG ATT ATA TTG CCG TTA-30). Each PCR reaction
contained 12.5 ll of 2 SYBR Premix Ex Taq II (Takara, Japan), 1 ll of cDNA template, and the gene-specific primer sets at a final concentration
of 0.1 lM. Ct values obtained for the Rps5 reactions
were used to standardize the Ct numbers for other immune-related
genes from the same samples. Melt curves obtained at the end of
the amplification confirmed that each primer pair produced a single
product with a single Tm. The t-tests were performed for the
analyses of relative expressions. A P value