Table 1 Primers used in this study

VHH1-F

GTCCTGGCTGCTCTTCTACAAGG

For library construction, first round of PCR reaction

VHH1-R

GGTACGTGCTGTTGAACTGTTCC

VHH2-F

CTGGCCCAGCCGGCCATGGCTCAGTTGCAGCTCGTG

For library construction, second round of PCR reaction

VHH2-R

AAGGAAAAAAGCGGCCGCTGAGGAAACGGTGACCTGGG

Detc-F

CCATGATTACGCCAAGCTTTGGAGCC

For positive rate identification of the library

Detc-R

CGATCTAAAGTTTTGTCGTCTTTCC

Exp-F

CGCGGATCCATGGCTCAGGTGCAGCTCA

For expression of nanobodies against SRMV

Exp-R

CCCAAGCTTTGGTTGTGGTTTTGGTGTCTTGGG