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*Email: mrsrini@tnau.ac.in (corresponding author)
The present investigation was carried out on the sac brood virus (SBV) in Apis cerana indica of Tamil Nadu during 2018–19. Colonies were examined in major beekeeping regions, and diagnosis of SBV using specific primers was done to amplify the 834bp fragments through RT-PCR. Later these were compared with that of RT-LAMP(Reverse Transcriptase-Loop Mediated Isothermal Amplification), and a new set of primers were designed. In the RT-LAMP, the samples with SBV reacted with royal blue coloured hydroxyl naphthalene blue (HNB) dye and produced sky blue coloured fluorescence in positive reaction while the original royal blue colour was retained in the virus free samples. From among the cDNA isolated from 20 supposedly SBV infected samples, 10 and 8 samples were detected to have the viral cDNA by RT-PCR and RT-LAMP, respectively. RT-PCR is thus the best method for SBV diagnosis in the laboratory while the RT-LAMP is suitable for field level diagnosis.
Apis cerana indica, sac brood virus, Tamil Nadu, RT-PCR, RT-LAMP, hydroxyl naphthalene blue, field and laboratory diagnostics