Maize defensin ZmDEF1 is involved in plant response to fungal phytopathogens
A seed-specific cDNA Zea mays defensin 1 (ZmDEF1), which encodes a novel plant defensin, was isolated from maize (Zea mays L. cv. NongDa108). ZmDEF1 contains a predicted signal peptide of 31 amino acids at the N-terminus domain and a mature peptide of 49 amino acids with a calculated molecular mass of 5.4 kDa. Expression data demonstrated that this gene is expressed specially in immature and mature seeds. In contrast to defensins from other plant species, the expression of ZmDEF1 cannot be detected in seedlings, even under induction of methyl jasmonate (MeJA) and abscisic acid (ABA). The recombinant ZmDEF1 displays an inhibitive activity against the fungal pathogen, Phytophthora parasitica var. nicotianae. Ectopic expression of the ZmDEF1 gene under the control of the cauliflower mosaic virus (CaMV) 35S promoter conferred enhanced tolerance against P. parasitica in transgenic tobacco plants.
Key words: Antifungal peptides, Phytophthora parasitica, plant defensin, seed specific, transgenic tobacco.