The b-32 ribosome inactivating protein from maize influences fumonisin accumulation in in-vitro bioassays


Fungi of the genus Fusarium are common plant pathogens mainly associated with cereal crops. In particular, Fusarium verticillioides Sacc. is the most common toxigenic fungus in maize worldwide, causing root, stalk, and ear rot. Fusarium spp. can produce a wide range of secondary metabolites, some of which can unfavourably affect human and animal health. Owing to the potential risks of fumonisins F. verticillioides secondary metabolites, new regulations for the allowable mycotoxin limit in food and feed have been put in place by most agencies worldwide. Plants act on the attack of pathogenic fungi through a complex network of active responses such as the production of proteins toxic or inhibitory to pathogens such as RIP (Ribosome-Inactivating-Protein). The RIP present in maize endosperm (termed b-32) has been widely investigated. Similarly to other RIPs, is accumulated in the seed as an inactive pro-RIP precursor, which is converted into an active form by proteolytic processing. To understand the relationships between structure and substrate specificity of the maize b-32 RIP protein, a series of recombinant b-32 sequences, by selective deleting of different domains (RIP b-32, RIP ∆N, RIP ∆C and RIP-∆C (Ala), were prepared. Recombinant sequences were expressed in Escherichia coli to obtain high levels of recombinant proteins, which were subsequently tested for their potential ability to reduce both the colonization of F. verticillioides and fumonisin accumulation.


Antifungal protein, Fusarium verticillioides, crop protection, Zea mays, mycotoxins

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Maydica - A journal devoted to maize and allied species

ISSN: 2279-8013