RESUMO
Mo-CBP3 is an antifungal protein produced by Moringa oleifera which has been investigated as potential candidate for developing transgenic crops. Before the use of novel proteins, food safety tests must be conducted. This work represents an early food safety assessment of Mo-CBP3, using the two-tiered approach proposed by ILSI. The history of safe use, mode of action and results for amino acid sequence homology using the full-length and short contiguous amino acids sequences indicate low risk associated to this protein. Mo-CBP3 isoforms presented a reasonable number of alignments (>35% identity) with allergens in a window of 80 amino acids. This protein was resistant to pepsin degradation up to 2 h, but it was susceptible to digestion using pancreatin. Many positive attributes were presented for Mo-CBP3. However, this protein showed high sequence homology with allergens and resistance to pepsin digestion that indicates that further hypothesis-based testing on its potential allergenicity must be done. Additionally, animal toxicity evaluations (e.g. acute and repeated dose oral exposure assays) must be performed to meet the mandatory requirements of several regulatory agencies. Finally, the approach adopted here exemplified the importance of performing an early risk assessment of candidate proteins for use in plant transformation programs.
Assuntos
Antígenos de Plantas/efeitos adversos , Proteínas Alimentares/efeitos adversos , Alimentos Geneticamente Modificados/efeitos adversos , Modelos Moleculares , Moringa oleifera/metabolismo , Proteínas de Plantas/efeitos adversos , Sementes/metabolismo , Alérgenos/efeitos adversos , Alérgenos/química , Alérgenos/genética , Alérgenos/metabolismo , Ração Animal/efeitos adversos , Ração Animal/microbiologia , Animais , Antígenos de Plantas/química , Antígenos de Plantas/genética , Antígenos de Plantas/metabolismo , Brasil , Quitina/metabolismo , Proteínas Alimentares/química , Proteínas Alimentares/metabolismo , Digestão , Hipersensibilidade Alimentar/etiologia , Hipersensibilidade Alimentar/prevenção & controle , Alimentos Geneticamente Modificados/microbiologia , Humanos , Ligantes , Fungos Mitospóricos/crescimento & desenvolvimento , Moringa oleifera/genética , Controle Biológico de Vetores/métodos , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/efeitos adversos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Isoformas de Proteínas/efeitos adversos , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Medição de Risco , Sementes/genética , Homologia de Sequência de AminoácidosRESUMO
This study reports on the antifungal activity of Dgui, a ConA-like lectin from Dioclea guianensis seeds. Dgui inhibited conidial germination but not mycelial growth of Colletotrichum gloeosporioides. The lectins ConA and ConM from Canavalia ensiformis and Canavalia maritima, respectively, share high levels of amino acid sequence similarity (>84%) with Dgui and have the same specificity toward glucose/mannose but had no effect on the fungus. Fluorescence microscopy showed that both Dgui and ConM bind to C. gloeosporioides ungerminated conidia. However, Dgui did not bind to C. gloeosporioides germinated conidia and germ tubes and was not inhibitory to mycelial growth. Because only Dgui inhibited germination of the fungus, C. gloeosporioides conidia might have surface-specific germination targets recognized by Dgui but not by its homologues, ConM and ConA. Therefore, Dgui is a candidate for biotechnological approaches for improving the resistance of various nutritionally and commercially important crops that are affected by C. gloeosporioides.
