The Effects of Destruxin A on Relish and Rel Gene Regulation to the Suspected Immune-Related Genes of Silkworm.

Weina Hu,Jingjing Wang,Guangwei He,Qiongbo Hu

doi:10.3390/molecules22010041

Weina Hu, Jingjing Wang + Show 2 more

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https://doi.org/10.3390/molecules22010041

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Abstract

Destruxin A (DA), a cyclodepsipeptidic mycotoxin of entomopathogenic fungus, Metarhizium anisopliae, has anti-immunity activity against insects, but the mechanism of immune regulation is not clear yet. In our previous experiment, the significant expression changes of Bm_nscaf2838_045, Bm_nscaf2674_066, and Bm_nscaf2767_133 genes in a silkworm’s hemocytes were found, which suggested that these genes might be involved in insect’s innate immunity. In the current experiment, the silkworm cell line Bm12 was used to survey the expression levels of these genes after the cells were treated with DA and the transcription factors BmRel, BmRelish1 and BmRelish2 were silenced by specific siRNA. The results indicated that, after the cells were treated by DA, the gene expression level of BmRelish2 was significantly downregulated, but BmRel and BmRelish1 were not changed. The results also showed that the gene expression levels of Bm_nscaf2838_045 and Bm_nscaf2674_066 had similar phenomena, i.e., downregulation with individual BmRelish1 gene silence or DA treatment, upregulation with combination of BmRelish1 gene silence and DA treatment, upregulation with individual BmRelish2 gene silence, and downregulation with combination of BmRelish2 gene silence plus DA treatment, but no changes in the BmRel gene silence combined with DA treatment. For the Bm_nscaf2767_133 gene, the downregulated expressions were found in individual BmRelish2 gene silence or DA treatment, upregulation in the combination treatment of BmRelish2 gene silence plus DA, and the individual treatment of BmRel or BmRelish1 silence. It is suggested that expressions of the Bm_nscaf2838_045 and Bm_nscaf2674_066 genes are closely related to the Imd signal pathway, but Bm_nscaf2767_133 genes might involve in both Toll and Imd pathways. Furthermore, the BmRelish1 gene acts as an activator and the BmRelish2 gene acts as a repressor for both Bm_nscaf2838_045 and Bm_nscaf2674_066 gene expressions. It also implies that DA may participate in the splicing process of BmRelish where BmRelish2 was promoted. Our research will provide new insights on the understanding of the activity mechanisms of destruxins.

Highlights

Destruxins are cyclodepsipeptidic mycotoxins with 39 analogues
Research has shown that Destruxin A (DA) can destroy an insect’s innate immune system, which includes breaking the balance between calcium ion and hydrogen ion in hemocytes [4], affecting the function of phagocytosis and encapsulation in hemocytes [5] and inhibiting the biosynthesis of the antibacterial peptides in drosophila [6]
DA probably promotes the formation of the BmRelish2 prior to the suggestsuggest that DAthat probably promotes the formation of the BmRelish2 transcripttranscript prior to the

Summary

Introduction

Destruxins are cyclodepsipeptidic mycotoxins with 39 analogues. Destruxin A (DA), the common analogue of entomopathogenic fungus, Metarhizium anisopliae, has substantial insecticidal activity [1,2,3].Research has shown that DA can destroy an insect’s innate immune system, which includes breaking the balance between calcium ion and hydrogen ion in hemocytes [4], affecting the function of phagocytosis and encapsulation in hemocytes [5] and inhibiting the biosynthesis of the antibacterial peptides in drosophila [6]. Destruxins are cyclodepsipeptidic mycotoxins with 39 analogues. Destruxin A (DA), the common analogue of entomopathogenic fungus, Metarhizium anisopliae, has substantial insecticidal activity [1,2,3]. Research has shown that DA can destroy an insect’s innate immune system, which includes breaking the balance between calcium ion and hydrogen ion in hemocytes [4], affecting the function of phagocytosis and encapsulation in hemocytes [5] and inhibiting the biosynthesis of the antibacterial peptides in drosophila [6]. Our previous research suggests that, relatively large doses. Our previous research suggests that, relatively large doses of DA is required to kill the silkworm (Bombyx mori) Bm12 cell, smaller dosages are sufficient to cause to morphological changes [7]. We found the expression of the of DA is required kill the silkworm (Bombyx mori)

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Discussion

Conclusion