Abstract:

【Aim】 To explore the molecular mechanism of Myzus persicae to adapt to UV-B stress.【Methods】 The full-length cDNA of the heat shock protein gene Hsp70 was cloned from M. persicae by using RT-PCR and RACE techniques, and its sequence characteristics were analyzed by bioinformatics methods. The relative expression levels of this gene in M. persicae adults exposed to UV-B stress for different time (0, 15, 30, 60, 90 and 120 min) were detected by qPCR. 【Results】 The cDNA of a Hsp70 gene was cloned from M. persicae and named as MpHsp70 (GenBank accession no.: MF509827). The full length of the gene is 2 221 bp and the open reading frame (ORF) is 1 965 bp, encoding 654 amino acids. The relative molecular weight of its encoded protein is 71.41 kD, and the isoelectric point (pI) is 5.34. The highly conserved sequence EEVD shows that this protein belongs to the cytoplasmic heat shock protein (Hsp). The phylogenetic relationship analysis showed that MpHsp70 is highly homologous to Hsp70s of various insects and shows the high conservation characteristic of Hsp70 gene. The qPCR results showed that the relative expression level of MpHsp70 in M. persicae adults increased first, achieved the highest at 30 min post exposure, and then decreased with the prolonged UV-B irradiation time. 【Conclusion】MpHsp70 gene in M. persicae can respond to UV-B stress and may play an important role in the adaptation of M. persicae to UV-B stress.

Key words: Myzus persicae; Hsp70 gene, UV-B stress, gene cloning, expression analysis