Does Mycorrhizal Biotechnology Modulate Lectin Accumulation in the Stem of <i>Schinus terebinthifolia</i> Raddi Seedlings?

It is well-established that mycorrhizal symbiosis can alter lectin expression in plant roots, whereas little is known about its role in lectin accumulation in other plant organs and whether such behavior is related to the production of antioxidant secondary metabolites. This study aimed to evaluate whether the lectin accumulation profile in the stems of <i>Schinus terebinthifolia</i> Raddi seedlings is modulated in response to inoculation with an arbuscular mycorrhizal fungus (AMF) consortium. A greenhouse experiment was set up with two inoculation treatments: a noninoculated control and an AMF treatment (consortium of <i>Acaulospora longula</i>, <i>Entrophospora etunicata</i>, and <i>Dentiscutata heterogama</i>). After 191 days, stem tissues were harvested to prepare aqueous extracts. Primary and secondary metabolites were quantified spectrophotometrically, and <i>in vitro</i> antioxidant activity was evaluated. The hemagglutinating activity assay was performed to detect lectins, and the specific hemagglutinating activity (SHA) was determined. The AMF consortium significantly (<i>p</i> ≤ 0.01) enhanced the accumulation of metabolites, antioxidant activity, and SHA by over 110%, in comparison to control plants. The anabolism of carbohydrates, proteins, and phenols was highly correlated (<i>r</i> ≥ 0.8) with stem SHA. To our knowledge, this is the first study demonstrating the effect of mycorrhizal symbiosis on the specific hemagglutinating activity of plant extracts, revealing the presence of bioactive lectins in <i>S. terebinthifolia</i> stems and its relation to the production of other bioactive compounds. It suggests that AMF can quantitatively and qualitatively modulate lectin accumulation, a process closely tied to the host's anabolism.