20‐Hydroxyecdysone enhances Immulectin‐1 mediated immune response against entomogenous fungus in Locusta migratoria

Abstract

Background Entomogenous fungi are important factors in biological control, but innate immunity of insects restricts the efficiency of fungus infection. 20‐hydroxyecdysone (20E) is involved in regulating the immune response of insects. Our previous studies have revealed that 20E enhances the expression of antibacterial peptides in the worldwide pest Locusta migratoria. However, the mechanism by which 20E controls innate immunity against entomogenous fungi is still unknown. Results In the present study, based on the transcriptome of L. migratoria fat bodies challenged by 20E, immulectin‐1 (LmIML‐1) was screened and identified to be involved in modulating antifungal immunity. Spatio‐temporal expression analysis showed LmIML‐1 was highly expressed in the fifth instar nymph stage, and mainly distributed in the fat bodies and hemolymph. Both exogenous and endogenous 20E could increase the transcription of LmIML‐1. In contrast, transcription of LmIML‐1 did not increase when the 20E signal was blocked by RNAi of LmEcR (ecdysone receptor). The expressed recombinant protein rLmIML‐1 possessed agglutination activity and promoted the encapsulation. RNA interference of LmIML‐1 reduced the encapsulation of hemocytes, decreased the antifungal activity of plasma against Metarhizium anisopliae and accelerated the death of nymphs under the stress of entomogenous fungus. Meanwhile, 20E did not increase the antifungal activity with silence of LmIML‐1 in L. migratoria. Conclusion 20E enhances antifungal immunity by activating immulectin‐1 in L. migratoria. Our findings indicate a potential mechanism of 20E systematically regulating innate immune response to resist pathogens and provide a well‐defined molecular target for improving biological control. © 2019 Society of Chemical Industry

Separation and HPLC Characterization of Active Natural Steroids in a Standardized Extract from the Serratula coronata Herb with Antiseborrheic Dermatitis Activity

“…Moreover, it has been reported that phytoecdysteroids improve skin quality by accelerating the healing of wounds and burns [ 36 , 37 ].Several studies [ 38 ] have claimed associations between Malassezia restricta lipase and SD. In light of this, ecdysteroids, especially 20-hydroxyecdysone, probably enhance antifungal immunity, resulting in a reduction of disease symptoms [ 39 ].…”

Molecular Characterization of Two Genes Encoding Novel Ca2+-Independent Phospholipase A2s from the Silkworm, Bombyx mori

“…In Spodoptera exigua, Se-sPLA2A has been reported to be regulated by pyriproxyfen, a juvenile hormone analog [12]. Moreover, a number of studies demonstrate that 20-hydroxyecdysone can play an important role in the metamorphosis process [20,22,27,28]. These results suggest that the PLA2A family may have a crucial biological role in the developmental process of insects.…”

Beauveria bassiana Ribotoxin (BbRib) Induces Silkworm Cell Apoptosis via Activating Ros Stress Response

“…After entering the haemocoel, it is necessary to overcome the host's innate immune defense response first and then effectively obtain the nutrients in the host for growth and reproduction. This ultimately leads to the death of the host insect [7,19]. Pathogenic fungi are induced by the secretions of insect body walls, hemolymph or plant roots, and there are great differences in the types and levels of gene expression.…”