Tithonia diversifolia is an invasive weed commonly found in tropical ecosystems. In this work, we investigate the influence of different abiotic environmental factors on the plant’s metabolite profile by multivariate statistical analyses of spectral data deduced by UHPLC-DAD-ESI-HRMS and NMR methods. Different plant part samples of T. diversifolia which included leaves, stems, roots and inflorescences were collected from two Brazilian states throughout a 24-month period, along with the corresponding monthly environmental data. A metabolomic approach employing concatenated LC-MS and NMR data was utilised for the first time to study the relationships between environment and plant metabolism. A seasonal pattern was observed for the occurrence of metabolites that included sugars, sesquiterpenes lactones and phenolics in the leaf and stem parts, which can be correlated to the amount of rainfall and changes in temperature. The distribution of the metabolites in the inflorescence and root parts were mainly affected by variation of some soil nutrients such as Ca, Mg, P, K and Cu. We highlight the environment-metabolism relationship for T. diversifolia and the combined analytical approach to obtain reliable data that contributed to a holistic understanding of the influence of abiotic environmental factors on the production of metabolites in various plant parts.

Summary: Feruloylation of arabinoxylan (AX) in grass cell walls is a key determinant of recalcitrance to enzyme attack, making it a target for improvement of grass crops, and of interest in grass evolution. Definitive evidence on the genes responsible is lacking so we studied a candidate gene that we identified within the BAHD acyl‐CoA transferase family. We used RNA interference (RNAi) silencing of orthologs in the model grasses Setaria viridis (SvBAHD01) and Brachypodium distachyon (BdBAHD01) and determined effects on AX feruloylation. Silencing of SvBAHD01 in Setaria resulted in a c. 60% decrease in AX feruloylation in stems consistently across four generations. Silencing of BdBAHD01 in Brachypodium stems decreased feruloylation much less, possibly due to higher expression of functionally redundant genes. Setaria SvBAHD01 RNAi plants showed: no decrease in total lignin, approximately doubled arabinose acylated by p‐coumarate, changes in two‐dimensional NMR spectra of unfractionated cell walls consistent with biochemical estimates, no effect on total biomass production and an increase in biomass saccharification efficiency of 40–60%. We provide the first strong evidence for a key role of the BAHD01 gene in AX feruloylation and demonstrate that it is a promising target for improvement of grass crops for biofuel, biorefining and animal nutrition applications.

Abscisic acid (ABA) is an essential phytohormone that regulates growth, development and adaptation of plants to environmental stresses. In Arabidopsis and other higher plants, ABA signal transduction involves three core components namely PYR/PYL/RCAR ABA receptors (PYLs), type 2C protein phosphatases (PP2Cs) and class III SNF-1-related protein kinase 2 (SnRK2s). In the present study, we reported the identification and characterization of the core ABA signaling components in Setaria viridis, an emerging model plant for cereals and feedstock crops presenting C4 metabolism, leading to the identification of eight PYL (SvPYL1 to 8), twelve PP2C (SvPP2C1 to 12) and eleven SnRK2 (SvSnRK2.1 through SvSnRK2.11) genes. In order to study the expression profiles of these genes, two different S. viridis accessions (A10.1 and Ast-1) were submitted to drought, salinity and cold stresses, in addition to application of exogenous ABA. Differential gene expression profiles were observed in each treatment and plant genotype, demonstrating variations of ABA stress responses within the same species. These differential responses to stresses were also assessed by physiological measurements such as photosynthesis, stomatal conductance and transpiration rate. This study allows a detailed analysis of gene expression of the core ABA signaling components in Setaria viridis submitted to different treatments and provides suitable targets for genetic engineering of C4 plants aiming tolerance to abiotic stresses.

Myrcia tomentosa (Aubl.) DC., Myrtaceae, found in Central Brazilian Cerrado and popularly known as “goiaba-brava”, belongs to the Myrcia genus, which has several species with medicinal properties such as: hypoglycemic, diuretic, hypotensive, antidiarrheal, antimicrobial and antitumor. The present study aimed to analyzed the environmental infl uence on concentrations of phenolic metabolites in M. tomentosa leaves. Compounds assayed in the leaves were: total phenols, tannins by protein precipitation, hydrolysable tannins and total fl avonoids and mineral nutrients, while soil fertility was also analyzed, all over during one year. The results were submitted to Pearson Correlation Analysis and stepwise Multiple Regression Analysis to investigate the relationship between phenolics and environment data. Analysis of variance and Cluster Analysis allowed indicated a high variability in samples from different sites. The results obtained suggests that content of phenolics from M. tomentosa leaves are infl uenced by environmental factors, particularly some foliar nutrients (Nl, Cal and Mnl), soil nutrients (Cas and Ks) and Rainfall

Lafoensia pacari A. St.-Hil., Lythraceae, a plant from the Cerrado known as pacari or dedaleiro, is widely used as an antipyretic, wound healing, anti-inflammatory, antidiarrheal and in the treatment of gastritis and cancer. Notable among the metabolite groups identified in leaves of L. pacari are the polyphenols, such as tannins and flavonoids, related to the pharmacological activities of pacari. Studies on the influence of environmental factors over production of major groups of secondary metabolites in pacari are important because they contribute data for its cultivation and harvest, and establish quantitative parameters of secondary metabolites in the plant drug. The objective of this study was to evaluate the influence of environmental factors on concentrations of phenolic metabolites in the leaves of L. pacari. Compounds quantified in the leaves were: total phenols, tannins by protein precipitation, hydrolysable tannins, total flavonoids, ellagic acid and mineral nutrients, while soil fertility was also analyzed, all over a period of one year. The data were analyzed using multivariate analysis, and the results suggest that metabolite concentrations in the leaves of this plant are influenced by seasonal factors, in particular the temperature and foliar micronutrients (Cu, Fe, Mn, Zn)