Effects of Trichoderma harzianum on Photosynthetic Characteristics and Fruit Quality of Tomato Plants

The beneficial role of fungi from the <i>Trichoderma</i> genus and its secondary metabolites in promoting plant growth, uptake and use efficiency of macronutrients and oligo/micro-nutrients, activation of plant secondary metabolism and plant protection from diseases makes it interesting for application in environmentally friendly agriculture. However, the literature data on the effect of <i>Trichoderma</i> inoculation on tomato fruit quality is scarce. Commercially used tomato cultivars were chosen in combination with indigenous <i>Trichodrema</i> species previously characterized on molecular and biochemical level, to investigate the effect of <i>Trichoderma</i> on photosynthetic characteristics and fruit quality of plants grown in organic system of production. Examined cultivars differed in the majority of examined parameters. Response of cultivar Gružanski zlatni to <i>Trichoderma</i> application was more significant. As a consequence of increased epidermal flavonols and decreased chlorophyll, the nitrogen balance index in leaves has decreased, indicating a shift from primary to secondary metabolism. The quality of its fruit was altered in the sense of increased total flavonoids content, decreased starch, increased Bioaccumulation Index (BI) for Fe and Cr, and decreased BI for heavy metals Ni and Pb. Higher expression of swolenin gene in tomato roots of more responsive tomato cultivar indicates better root colonization, which correlates with observed positive effects of <i>Trichodrema</i>.