Cloning and expression of a PR5-like protein from Arabidopsis: inhibition of fungal growth by bacterially expressed protein.
Pathogenesis-related (PR)-5 proteins are a family of proteins that are induced by different phytopathogens in many plants and share significant sequence similarity with thaumatin. We isolated a complementary DNA (ATLP-3) encoding a PR5-like protein from Arabidopsis which is distinct from two other previously reported PR5 cDNAs from the same plant species. The predicted ATLP-3 protein with its amino-terminal signal sequence is 245 amino acids in length and is acidic with a pl of 4.8. The deduced amino acid sequence of ATLP-3 shows significant sequence similarity with PR5 and thaumatin-like proteins from Arabidopsis and other plants and contains a putative signal sequence at the amino-terminus. The expression of ATLP-3 and a related gene (ATLP-1) that we previously isolated from Arabidopsis was induced by pathogen infection and salicylic acid, a known inducer of pathogenesis-related genes. Southern blot analysis indicates that the ATLP-1 and ATLP-3 are coded by single-copy genes. To study the effect of ATLP-1 and ATLP-3 proteins on fungal growth, the cDNA regions corresponding to putative mature protein were expressed in Escherichia coli and the cDNA encoded proteins were purified. ATLP-1 and ATLP-3 proteins cross-reacted with anti-osmotin and anti-zeamatin antibodies. ATLP-3 protein showed antifungal activity against several fungal pathogens suggesting that ATLP-3 may be involved in plant defense against fungal pathogens.
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Department of Biology, Colorado State University, Fort Collins 80523, USA.
Reddy
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D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000494:pharmacology*; D017360:Arabidopsis / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002176:Candida albicans / Q000187:drug effects; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D008826:Microbial Sensitivity Tests; D003904:Mitosporic Fungi / Q000187:drug effects; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000235:genetics; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D011994:Recombinant Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013549:Sweetening Agents
D000935:Antifungal Agents; D018076:DNA, Complementary; D010940:Plant Proteins; D011994:Recombinant Proteins; D013549:Sweetening Agents; C053376:pathogenesis-related proteins, plant; C003427:thaumatin protein, plant