RESUMO
Plants have developed many mechanisms to protect themselves against most potential microbial pathogens and diseases. Among these mechanisms, pathogenesis-related proteins are produced as part of the active defence to prevent attack. In this study, a full-length cDNA encoding the CsPR10 protein was identified in fresh saffron stigmas (Crocus sativus). The deduced amino acid sequence from the nucleotide sequence of the coding region showed homology with PR10 proteins. The clone expressed as a protein in fusion with a GST tag produced a 47-kDa protein in E. coli. CsPR10 had ribonuclease activity, with features common to class II-type ribonucleases; its specific activity was quantified as 68.8 U·mg(-1) protein, thus falling within the range of most PR10 proteins exhibiting RNase activity. Antifungal activity of CsPR10 was assayed against Verticillium dahliae, Penicillium sp. and Fusarium oxysporum. CsPR10 inhibited only F. oxysporum growth, and antifungal potency was reflected in a IC(50) of 8.3 µm. Expression analysis showed the presence of high transcript levels in anther and tepal tissues, low levels in stigmas and roots, and no signal detected in leaves. This protein seems to be involved in the active defence response through activation of the jasmonic acid pathway.
Assuntos
Crocus/genética , Proteínas de Plantas/metabolismo , Ribonucleases/metabolismo , Sequência de Aminoácidos , Clonagem Molecular , Crocus/metabolismo , Crocus/microbiologia , DNA Complementar/genética , DNA de Plantas/genética , Flores/genética , Flores/metabolismo , Fusarium/patogenicidade , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Penicillium/patogenicidade , Filogenia , Proteínas de Plantas/genética , Estrutura Secundária de Proteína , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Ribonucleases/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Verticillium/patogenicidadeRESUMO
BACKGROUND: Lipid transfer proteins (LTPs) are relevant allergens, and have recently been proposed as model plant allergens from fruit, vegetables, seeds, and pollens. However, no LTP spice allergen has been characterized to date. OBJECTIVES: To identify and isolate saffron LTPs and to explore their relevance in saffron allergy. METHODS: Six patients with rhinitis and positive skin prick test (SPT) results to saffron extract were selected. Two recombinant LTPs from saffron were isolated, cloned into pPIC9 plasmid, and produced in Pichia pastoris. Immunoglobulin (Ig) E immunodetection and enzyme-linked immunosorbent assays were performed with the 2 purified allergens and with the major peach allergen Pru p 3. RESULTS: Full cDNA corresponding to 2 saffron LTP variants was isolated and expressed in P pastoris. The molecular weight of rCro s 3.01 and rCro s 3.02 was 9.15 kDa and 9.55 kDa, respectively. The sequences obtained had a 47% identity with each other and 51% and 43% with Pru p 3. Both proteins were recognized by anti-Pru p 3 antibodies. Specific IgE to the purified allergens was found in 50% of patients for rCro s 3.01 and 33% for rCro s 3.02 and Pru p 3 in the saffron-allergic patients. CONCLUSIONS: Our results indicated that rCro s 3.01 and rCro s 3.02 are minor allergens of saffron, at least in the study patients. To our knowledge, this is the first report on the implication of LTPs in spice allergy.
