Harzianic acid: a novel siderophore from Trichoderma harzianum


Correspondence: Francesco Vinale, CNR – Istituto per la Protezione delle Piante (IPP-CNR), Via Università 133, 80055 Portici, Naples, Italy. Tel.: +39 081 253 9338; fax: +39 081 253 9339; e-mail: f.vinale@ipp.cnr.it


Agriculture-relevant microorganisms are considered to produce secondary metabolites during processes of competition with other micro- and macro-organisms, symbiosis, parasitism or pathogenesis. Many different strains of the genus Trichoderma, in addition to a direct activity against phytopathogens, are well-known producers of secondary metabolites and compounds that substantially affect the metabolism of the host plant. Harzianic acid is a Trichoderma secondary metabolite, showing antifungal and plant growth promotion activities. This report demonstrates the ability of this tetramic acid to bind with a good affinity essential metals such as Fe3+, which may represent a mechanism of iron solubilisation that significantly alters nutrient availability in the soil environment for other microorganisms and the host plant.