A central pillar of modern weed control is the discovery of new herbicides which are nontoxic to humans and the environment and which have low application dosage. The natural products found in plants and microorganisms are well suited in this context because they are generally nontoxic and have a wide variety of biological activities. In this work, Diaporthe phaseolorum (Dp), Penicillium simplicissimum (Ps) and Trichoderma spirale (Ts) (methanolic extracts) were evaluated as photosynthesis and plant growth inhibitors in Senna occidentalis and Ipomoea grandifolia. The most significant results were observed for Ts and Dp in S. occidentalis and I. grandifolia, respectively. Ts reduced PI_(abs), ET₀/CS₀, PHI(E₀) and PSI₀ parameters by 64, 28, 40 and 38%, respectively, indicating a reduction on electron transport efficiency. Additionally, Ts decreased shoot length by 9%, affecting the plant growth. Dp reduced PI_(abs), ET₀/CS₀ and PHI(E₀) parameters by 50, 20, 26 and 22%, respectively, revealing the inhibition competency on PSII acceptor site. Furthermore, Dp decreased by 50% the shoot length on germination assay. Thus, the phytotoxic behaviors based on endophytic fungal extracts may serve as a valuable tool in the further development of a bioherbicide since natural products represent an interesting alternative to replace commercial herbicides.

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 as 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 β-alanine in lower concentrations as 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.

Evaluation of p-benzoquinones derivatives as post-emergent plant growth inhibitor / Avaliação de derivados p-benzoquinonas como inibidores pós-emergentes do crescimento vegetal

Evaluation of p-benzoquinones derivatives as post-emergent plant growth inhibitor / Avaliação de derivados p-benzoquinonas como inibidores pós-emergentes do crescimento vegetal