Developmental regulation and antifungal activity of a growth-blocking peptide from the beet armyworm Spodoptera exigua.
Insect cytokine growth-blocking peptides (GBPs) are involved in growth regulation and the innate immune response. However, the microbial binding and antimicrobial activities of GBPs remain unclear. Here, we investigate the developmental role and antifungal activity of a GBP from the beet armyworm Spodoptera exigua (SeGBP). Sequence analysis predicted that mature SeGBP consists of 24 amino acid residues, including 2 cysteine residues. During S. exigua development, SeGBP is constitutively expressed in the fat body during the larval and adult stages but not in pupae. SeGBP expression is up-regulated by 20-hydroxyecdysone and down-regulated by juvenile hormone analog. Recombinant SeGBP purified from baculovirus-infected insect cells retards the growth of S. exigua larvae. Additionally, SeGBP expression is acutely induced in the fat body after injection with Escherichia coli, Bacillus thuringiensis, or Beauveria bassiana. Recombinant SeGBP can bind to B. bassiana but not to E. coli or B. thuringiensis. Consistent with these findings, SeGBP shows antifungal activity against B. bassiana. Therefore, these results provide insight into the role of SeGBP during the innate immune response following microbial infection, and furthermore, they suggest a novel function for SeGBP as a direct antifungal agent against entomopathogenic fungi, such as B. bassiana.
['Wan|Hu|H|', 'Lee|Kwang Sik|KS|', 'Kim|Bo Yeon|BY|', 'Yuan|Miao|M|', 'Zhan|Sha|S|', 'Lu|Yanhui|Y|', 'You|Hong|H|', 'Li|Jianhong|J|', 'Jin|Byung Rae|BR|']
D000595:Amino Acid Sequence D000818:Animals D000935:Antifungal Agents D001413:Bacillus thuringiensis D052982:Beauveria D015152:Blotting, Northern D015153:Blotting, Western D003001:Cloning, Molecular D016207:Cytokines D018076:DNA, Complementary D004441:Ecdysterone D004926:Escherichia coli D005216:Fat Body D018507:Gene Expression Regulation, Developmental D015801:Helminth Proteins D054884:Host-Pathogen Interactions D019476:Insect Proteins D007605:Juvenile Hormones D007814:Larva D008969:Molecular Sequence Data D011994:Recombinant Proteins D017422:Sequence Analysis, DNA D017386:Sequence Homology, Amino Acid D061987:Sf9 Cells D018411:Spodoptera
Antifungal activity Growth-blocking peptide Beet armyworm Spodoptera exigua Immunity Hormonal regulation