%A HUANG Yan-Ling, HUANG Shi-Yi, LI Shu-Qiang, HE Yan-Ying, CHEN Ze-Min, LIU Ji-Sheng %T Expression of BmToll9 genes responding to peptidoglycan and Staphylococcus aureus in larval Bombyx mori %0 Journal Article %D 2019 %J Acta Entomologica Sinica %R 10.16380/j.kcxb.2019.04.002 %P 398-406 %V 62 %N 4 %U {http://www.insect.org.cn/CN/abstract/article_6340.shtml} %8 2019-04-20 %X

Aim Toll receptors of Toll signaling pathway, an important immune signaling pathway of insects, are essential to maintain immune response against invading exogenous microorganisms in insects. This study aims to explore the influence of peptidoglycan (PGN) and Staphylococcus aureus on the expression of the Toll receptor genes BmToll9-1 and BmToll9-2 in the silkworm, Bombyx mori. Methods PGN, the main component in cell wall of Gram-positive bacteria, and a Gram-positive bacterium S. aureus were respectively injected into the day-1 5th instar larvae of B. mori to induce the immune response. The relative expression levels of BmToll9-2 and BmToll9-1 in the midgut, epidermis, fat body and silk glands of the larvae at different time points post injection were detected by real-time quantitative PCR. Results After injection of PGN or S. aureus into the 5th instar larvae of B. mori, BmToll9-2 was differentially expressed at different time points and in different tissues. Injection of PGN or S. aureus induced up-regulation of the expression of BmToll9-2 in the midgut of the 5th instar larvae, achieving the best induction effect at 3 and 6 h post injection, respectively, and the induction effect of S. aureus was better than that of PGN. Injection of S. aureus induced up-regulation of the expression of BmToll9-2 in the epidermis, fat body and silk glands of the 5th instar larvae, achieving the best induction effects at 24, 6, and 24 h post injection, respectively. Injection of S. aureus also induced up-regulation of the expression of the homogenous BmToll9-1. Conclusion The expression of BmToll9 genes in different tissues of B. mori larvae is up-regulated after injection of PGN or S. aureus, suggesting that BmToll9 genes are involved in the immune response of B. mori against PGN and S. aureus.