The aim of this work was to identify and quantify the metabolites present in the roots of Combretum lanceolatum inoculated with its endophytic fungi. The metabolomics was accomplished using the 1H nuclear magnetic resonance (NMR) spectral data and evaluated via rNMR software and Madison Metabolomics Consortium Database (MMCD). The principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) showed that plants inoculated with Trichoderma spirale (Ts) present differentiation and discrimination over the time compared to control. Seven days after Ts fungal inoculation, 15 metabolites were identified at different concentrations comparing to the control plants. The plants inoculated with Ts fungus present the metabolites spermidine and pantothenate in higher concentrations and 3-hydroxybutyric acid and b-alanine in lower concentrations compared to control plants, indicating any response to biotic stress. These metabolites are involved in various plant processes, including secondary metabolites biosynthesis, energy metabolism and self-defense. Therefore, this work demonstrates the diversification of primary metabolites composition influenced by endophytes inoculation.

Dois produtos naturais produzidos por Cladosporium uredinicola, um fungo endofítico isolado da goiaba, tiveram seus efeitos sobre a fotossíntese avaliados. Os compostos inibiram o fluxo de elétrons (basal, fosforilante e desacoplado) de água a metilviologênio (MV). Esses compostos atuam como inibidores da reação de Hill em tilacóides de espinafre frescos. Esses policetídeos pertencem à classe dos depsídeos e inibiram o fluxo de elétrons das reações parciais do fotossistema II (PS II) de água a 2,5-dicloro-1,4-benzoquinona (DCBQ), de água a silicomolibdato de sódio (SiMo Na+), e ainda inibiram parcialmente de 1,5-difenilcarbazida (DPC) a 2,6-dicloroindofenol (DCPIP). Esses resultados estabeleceram que os sítios de inibição dos depsídeos estão localizados tanto no lado doador quanto no aceptor do PS II, entre P680 e Q A. Medidas de fluorescência da clorofila a corroboraram para elucidar esse mecanismo de ação. Nenhum dos compostos inibiu o fluxo de elétrons no fotossistema I (PS I).

Two natural products produced by Cladosporium uredinicola, an endophytic fungus isolated from guava fruit, were evaluated for their effects on photosynthesis. Both of them inhibited electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV), acting as Hill reaction inhibitors in freshly lysed spinach thylakoids. These polyketides, belonging to depsides class, inhibited partial reactions of photosystem II (PS II) electron flow from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), from water to sodium silicomolybdate (SiMo Na+), and partially inhibited electron flow from 1,5-diphenylcarbazide (DPC) to 2,6-dichloroindophenol (DCPIP). These results established that the depsides sites of inhibition are located on the donor and acceptor sides of PS II, between P680 and Q A. Chlorophyll a fluorescence measurements corroborated this mechanism of action. None of the tested compounds inhibited photosystem I (PS I) electron transport.