title: Bombyx mori cecropin A has a high antifungal activity to entomopathogenic fungus Beauveria bassiana.
abstract: A cDNA encoding cecropin A (CecA) was cloned from the larvae of silkworm, Bombyx mori, using RT-PCR. It encodes a protein of 63 amino acids, containing a 22 amino acid signal peptide and a 37 amino acid mat peptide of functional domain. The CecA secondary structure contains two typical amphiphilic α-helices. Real-time qPCR analysis revealed that CecA was expressed in all the tissues tested, including cuticle, fat body, hemocytes, Malpighian tubule, midgut and silk gland in the silkworm larvae with the highest expression in the fat body and hemocytes. The gene expression of B. mori CecA was rapidly induced by Beauveria bassiana challenge and reached maximum levels at 36h after inoculation in third instar larvae. In the fifth instar larvae infected with B. bassiana, the relative expression level of CecA was upregulated in fat body and hemocytes, but not in cuticle, Malpighian tubule, midgut and silk gland. The cDNA segment of the CecA was inserted into the expression plasmid pET-30a(+) to construct a recombinant expression plasmid. Western blot results revealed that his-tagged fusion protein was successfully expressed and purified. Then the mat peptide of CecA was chemically synthesized with C-terminus amidation for in vivo antifungal assay and purity achieved 93.7%. Mass spectrometry and SDS-PAGE showed its molecular weight to be 4046.95Da. Antifungal assays indicated that the B. mori CecA had a high antifungal activity to entomopathogenic fungus B. bassiana both in vitro and in vivo in the silkworm larvae. This is the first report that the CecA is effective to inhibit B. bassiana inside the body of silkworm.
authors.affiliation: Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, Jiangsu, China; Zhenjiang College, Zhenjiang 21200, Jiangsu, China.
authors.forename: Dingding
authors.initials: D
authors.lastname: Lu
authors.affiliation: Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, Jiangsu, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Geng
authors.affiliation: Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, Jiangsu, China.
authors.forename: Chengxiang
authors.initials: C
authors.lastname: Hou
authors.affiliation: Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, Jiangsu, China.
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, Jiangsu, China.
authors.forename: Guangxing
authors.initials: G
authors.lastname: Qin
authors.affiliation: Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, Jiangsu, China. Electronic address: guoxijie@126.com.
authors.forename: Xijie
authors.initials: X
authors.lastname: Guo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology*; D052982:Beauveria / Q000187:drug effects* / Q000472:pathogenicity; D012831:Bombyx / Q000235:genetics* / Q000382:microbiology*; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D054884:Host-Pathogen Interactions / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000382:microbiology; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D019476:Insect Proteins; D011994:Recombinant Proteins; C031161:cecropin A
keywords: Beauveria bassiana; Bombyx mori; antifungal activity; cecropin A