Molecular cloning and characterization of a β-1,3-glucan recognition protein from Plutella xylostella (L.)

The β-glucan recognition proteins (βGRPs) play a significant role as important pattern recognition proteins (PRPs) for recognizing conserved surface determinants of pathogens and trigger complex signaling pathways in invertebrates. In the present study, a full-length cDNA 1793bp encoding 479 amino acids and βGRP1 was obtained from Plutella xylostella by reverse transcription PCR (RT-PCR) (designed as P×βGRP1) which showed significant similarities with other insect's βGRPs. The transcription level was constitutively expressed and upregulated by microbial induction in all life stages of P. xylostella. Tissue distribution showed P×βGRP1 to be mainly expressed in fat body as detected by quantitative real-time PCR (qRT-PCR) and immunohistochemistry. Subsequent to knock down the P×βGRP1 expression and the transcripts of Toll-like receptor, cecropin 1 and cecropin 2 decreased in P. xylostella. Meanwhile, the bacterial colonies increased and the expression of four AMP genes decreased on injection of anti-P×βGRP1 into Bombyx mori. The results demonstrated that P×βGRP1 can play a vital role in response to the expression of AMP genes in P. xylostella.