Effects of Foliar Treatment with a Trichoderma Plant Biostimulant Consortium on Passiflora caerulea L. Yield and Quality

Abstract

<b></b>The influence of spore concentration on the ability of a <i>Trichoderma</i> consortium to colonize the <i>Passiflora caerulea</i> phyllosphere was evaluated by determining the effects of foliar treatments with two spore concentrations, in two repeated treatments, on the morphological, physiological, and ultrastructural characteristics, and on the yield and quality of <i>P. caerulea</i>. The studied crop quality features were related to its nutraceutical use: the accumulation of polyphenols and flavonoids, antioxidant activity, and effects on mouse fibroblast L929 cells. The <i>Trichoderma</i> consortium consisted of two strains, <i>T. asperellum</i> T36b and <i>T. harzianum</i> Td50b, and the concentrations used were 10⁶ colony forming units (cfu)/mL and 10⁸ cfu/mL. As a reference treatment, a commercial product that was based on herbs and algal extracts was used. As compared to the negative control, the treatment with the <i>Trichoderma</i> consortium at 10⁸ cfu/mL concentration determines the accumulation of higher level of polyphenols and flavonoids and increased antioxidant activity. This enhancement of <i>P. caerulea</i> quality characteristics after treatment with the higher concentration of <i>Trichoderma</i> consortium was associated with larger leaves, increased number and size of chloroplasts, improved plant physiology characteristics, and an increased yield. The treatment with high concentration of <i>Trichoderma</i> consortium spores promotes phyllosphere colonization and benefits both crop yield and quality.