Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou, China.
College of Plant Protection, Hainan University, Haikou, China.
Insect Mol Biol. 2021 Feb;30(1):102-112. doi: 10.1111/imb.12681. Epub 2020 Nov 17.
Antifungal innate immunity is an important defence used by insects against entomogenous fungi. However, the downstream target antifungal peptides of different immune signalling pathways are unknown. We found that the Toll, Janus kinase/signal transducer and activator of transcription (Jak/STAT) and Immunodeficiency (IMD) signalling pathways in the silkworm, Bombyx mori, can be activated by Beauveria bassiana. Inhibition of the Toll, IMD and Jak/STAT signalling pathways reduced the antifungal activities of silkworm haemolymph. We verified the target antifungal peptides of different immune signalling pathways. The expression patterns of five anti-fungal peptide genes in silkworm larvae and BmN cells were detected after blocking or over-expressing the immune signalling pathways. The Toll signalling pathways mediated the expression of Bmcecropin A, Bmattacin 1 and Bmgloverin 2; IMD signalling pathways mediated Bmenbocin 1, Bmgloverin 2 and Bmattacin 1; Jak/STAT signalling pathways mediated Bmstorage protein 30K-19G1 (Bmsp 1), Bmattacin 1 and Bmcecropin A. These data indicated that anti-microbial peptide genes in B. mori evolved through expansion and selection of existing genes to adapt to the challenge of invasive microorganisms such as fungi. This information provides insight into the antifungal immune responses in B. mori and aids understanding of insect immune regulation mechanisms.
昆虫先天抗真菌免疫是其抵御虫生真菌的重要防御机制。然而，不同免疫信号通路的下游靶抗真菌肽尚不清楚。我们发现家蚕的 Toll、Janus 激酶/信号转导和转录激活因子（Jak/STAT）和免疫缺陷（IMD）信号通路可以被球孢白僵菌激活。抑制 Toll、IMD 和 Jak/STAT 信号通路会降低家蚕血液的抗真菌活性。我们验证了不同免疫信号通路的靶抗真菌肽。在阻断或过表达免疫信号通路后，检测了家蚕幼虫和 BmN 细胞中 5 种抗真菌肽基因的表达模式。Toll 信号通路介导 Bmcecropin A、Bmattacin 1 和 Bmgloverin 2 的表达；IMD 信号通路介导 Bmenbocin 1、Bmgloverin 2 和 Bmattacin 1 的表达；Jak/STAT 信号通路介导 Bmstorage protein 30K-19G1（Bmsp 1）、Bmattacin 1 和 Bmcecropin A 的表达。这些数据表明，家蚕抗菌肽基因是通过对现有基因的扩张和选择进化而来的，以适应真菌等入侵微生物的挑战。这些信息为家蚕的抗真菌免疫反应提供了深入的了解，并有助于理解昆虫的免疫调节机制。
