| Title: | Arabidopsis vegetative storage protein is an anti-insect acid phosphatase |
| Author(s): | Liu Y; Ahn JE; Datta S; Salzman RA; Moon J; Huyghues-Despointes B; Pittendrigh B; Murdock LL; Koiwa H; Zhu-Salzman K; |
| Address: | "Department of Entomology, Texas A&M University, College Station, TX 77843, USA" |
| ISSN/ISBN: | 0032-0889 (Print) 1532-2548 (Electronic) 0032-0889 (Linking) |
| Abstract: | "Indirect evidence previously suggested that Arabidopsis (Arabidopsis thaliana) vegetative storage protein (VSP) could play a role in defense against herbivorous insects. To test this hypothesis, other AtVSP-like sequences in Arabidopsis were identified through a Basic Local Alignment Search Tool search, and their transcriptional profiles were investigated. In response to methyl jasmonate application or phosphate starvation, AtVSP and AtVSP-like genes exhibited differential expression patterns, suggesting distinct roles played by each member. Arabidopsis VSP2 (AtVSP2), a gene induced by wounding, methyl jasmonate, insect feeding, and phosphate deprivation, was selected for bacterial expression and functional characterization. The recombinant protein exhibited a divalent cation-dependent phosphatase activity in the acid pH range. When incorporated into the diets of three coleopteran and dipteran insects that have acidic gut lumen, recombinant AtVSP2 significantly delayed development of the insects and increased their mortality. To further determine the biochemical basis of the anti-insect activity of the protein, the nucleophilic aspartic acid-119 residue at the conserved DXDXT signature motif was substituted by glutamic acid via site-directed mutagenesis. This single-amino acid alteration did not compromise the protein's secondary or tertiary structure, but resulted in complete loss of its acid phosphatase activity as well as its anti-insect activity. Collectively, we conclude that AtVSP2 is an anti-insect protein and that its defense function is correlated with its acid phosphatase activity" |
| Keywords: | Acetates/pharmacology Acid Phosphatase/chemistry/genetics/*metabolism/pharmacology Amino Acid Sequence Animals Arabidopsis/enzymology/*metabolism Arabidopsis Proteins/chemistry/genetics/*metabolism/pharmacology Cyclopentanes/pharmacology Drosophila/drug e; |
| Notes: | "MedlineLiu, Yilin Ahn, Ji-Eun Datta, Sumana Salzman, Ron A Moon, Jaewoong Huyghues-Despointes, Beatrice Pittendrigh, Barry Murdock, Larry L Koiwa, Hisashi Zhu-Salzman, Keyan eng Research Support, Non-U.S. Gov't 2005/11/01 Plant Physiol. 2005 Nov; 139(3):1545-56. doi: 10.1104/pp.105.066837. Epub 2005 Oct 28" |
