Development of a Biological Control Strategy against Fusariosis and Rabies of Fuentesaúco-Chickpea (PGI) through the Use of the Trichoderma Fungus ^†

The Protected Geographical Indication (PGI) Fuentesaúco-Chickpea (F-C) includes a legume crop developed in the south of the province of Zamora (Spain), of great agronomic, economic, and cultural importance for the area, as well as gastronomically on a global scale. Its cultivation is mainly affected by the fungal diseases called fusariosis (caused by Fusarium oxysporum f. sp. ciceri) and rabies (caused by Ascochyta rabiei). Through an in vitro antagonism study, we were able to select the species Trichoderma atroviride, T. hamatum, T. harzianum, and T. koningii as the most effective against both pathogens, thanks to mechanisms of action such as mycoparasitism, antibiosis, and/or competition for space and/or nutrients. Subsequently, these four species were used in studies with F-C plants and both pathogens, inoculating Trichoderma radicularly. Using this methodology, we described how T. atroviride and T. koningii were able to control F. oxysporum f. sp. ciceri both directly and by activating plant defenses, in the case of T. koningii. On the other hand, the species T. hazianum and T. koningii were able to significantly reduce foliar infection with A. rabiei, by activating systemic plant defense responses. Regarding the productivity of F-C, the species T. hamatum and T. koningii were able to significantly increase the formation of grains in each plant. Therefore, T. koningii is capable of controlling both pathogens under greenhouse conditions, in addition to increasing their productivity.