title: Genomic and functional characterization of coleopteran insect-specific α-amylase inhibitor gene from Amaranthus species.
abstract: The smallest 32 amino acid α-amylase inhibitor from Amaranthus hypochondriacus (AAI) is reported. The complete gene of pre-protein (AhAI) encoding a 26 amino acid (aa) signal peptide followed by the 43 aa region and the previously identified 32 aa peptide was cloned successfully. Three cysteine residues and one disulfide bond conserved within known α-amylase inhibitors were present in AhAI. Identical genomic and open reading frame was found to be present in close relatives of A. hypochondriacus namely Amaranthus paniculatus, Achyranthes aspera and Celosia argentea. Interestingly, the 3'UTR of AhAI varied in these species. The highest expression of AhAI was observed in A. hypochondriacus inflorescence; however, it was not detected in the seed. We hypothesized that the inhibitor expressed in leaves and inflorescence might be transported to the seeds. Sub-cellular localization studies clearly indicated the involvement of AhAI signal peptide in extracellular secretion. Full length rAhAI showed differential inhibition against α-amylases from human, insects, fungi and bacteria. Particularly, α-amylases from Helicoverpa armigera (Lepidoptera) were not inhibited by AhAI while Tribolium castaneum and Callosobruchus chinensis (Coleoptera) α-amylases were completely inhibited. Molecular docking of AhAI revealed tighter interactions with active site residues of T. castaneum α-amylase compared to C. chinensis α-amylase, which could be the rationale behind the disparity in their IC50. Normal growth, development and adult emergence of C. chinensis were hampered after feeding on rAhAI. Altogether, the ability of AhAI to affect the growth of C. chinensis demonstrated its potential as an efficient bio-control agent, especially against stored grain pests.
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.
authors.forename: Amey J
authors.initials: AJ
authors.lastname: Bhide
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.
authors.forename: Sonal M
authors.initials: SM
authors.lastname: Channale
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.
authors.forename: Yashpal
authors.initials: Y
authors.lastname: Yadav
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.
authors.forename: Kabita
authors.initials: K
authors.lastname: Bhattacharjee
authors.affiliation: Department of Biochemistry, Shivaji University, Kolhapur, 416 004, India.
authors.forename: Pankaj K
authors.initials: PK
authors.lastname: Pawar
authors.affiliation: School of Life Sciences, North Maharashtra University, Jalgaon, 425 001, India.
authors.forename: V L
authors.initials: VL
authors.lastname: Maheshwari
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.
authors.forename: Vidya S
authors.initials: VS
authors.lastname: Gupta
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.
authors.forename: Sureshkumar
authors.initials: S
authors.lastname: Ramasamy
authors.affiliation: Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India. ap.giri@ncl.res.in.
authors.forename: Ashok P
authors.initials: AP
authors.lastname: Giri
mesh_terms: D029044:Achyranthes / Q000378:metabolism; D027721:Amaranthus / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D034762:Celosia / Q000378:metabolism; D003001:Cloning, Molecular; D001517:Coleoptera / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000378:metabolism* / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D008958:Models, Molecular; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D021381:Protein Transport; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D010940:Plant Proteins; D000516:alpha-Amylases
keywords: Amaranthus hypochondriacus; Callosobruchus chinensis; Signal peptide; Tribolium castaneum; α-Amylase; α-Amylase inhibitor