The controlled production of these compounds
could improve biofertilization [44]. Together with the
synthesis or stimulation of phytohormone production, most
Trichoderma strains acidify their surrounding environment
by secreting organic acids, such as gluconic, citric or fumaric
acid [26]. These organic acids result from the metabolism of
other carbon sources, mainly glucose, and, in turn, are able to
solubilize phosphates, micronutrients and mineral cations
including iron, manganese and magnesium