Metabolomic approaches to explore chemodiversity in seeds of guaraná (Paullinia cupana) using UPLC-QTOF-MSE and NMR analysis.

The growing interest in health and well-being has spurred the evolution of functional foods, which provide enhanced health benefits beyond basic nutrition. Guaraná seeds (Paullinia cupana) have been widely studied and used as a functional food due to their richness in caffeine, phenolic compounds, amino acids, and other nutrients. This has established guaraná as a significant food supplement, with Brazil being the largest producer of the world. This study aims to propose a set of analytical methods to chemically evaluate fifty-six different guaraná clones, from the Guaraná Germplasm Active Bank, to accommodate the diverse requirements of the food industry. Metabolomic approaches were employed, in which a non-target metabolomic analysis via UPLC-QTOF-MSE led to the annotation of nineteen specialized metabolites. Furthermore, targeted metabolomics was also used, leading to the identification and quantification of metabolites by NMR. The extensive data generated were subjected to multivariate analysis, elucidating the similarities and differences between the evaluated guaraná seeds, particularly concerning the varying concentration levels of the metabolites. The metabolomics approach based on the combination of UPLC-QTOF-MSE, NMR and chemometric tools provided sensitivity, precision and accuracy to establish the chemical profiles of guaraná seeds. In conclusion, evaluating and determining the metabolic specificities of different guarana clones allow for their application in the development of products with different levels of specific metabolites, such as caffeine. This caters to various purposes within the food industry. Moreover, the recognized pharmacological properties of the annotated specialized metabolites affirm the use of guarana clones as an excellent nutritional source.

Isolation and Identification of Pigment-Producing Endophytic Fungi from the Amazonian Species Fridericia chica.

Pigments of fungal origin have aroused increasing interest in the food dye and cosmetic industries since the global demand for natural dyes has grown. Endophytic microorganisms are a source of bioactive compounds, and Amazonian plant species can harbor fungi with a wide range of biotechnological applications. Popularly known in Brazil as crajiru, Fridericia chica is a medicinal plant that produces a red pigment. In this study, a total of 121 fungi were isolated in potato dextrose agar from three plants. We identified nine pigment-producing endophytic fungi isolated from branches and leaves of F. chica. The isolates that showed pigment production in solid media were molecularly identified via multilocus analysis as Aspergillus welwitschiae, A. sydowii, Curvularia sp., Diaporthe cerradensis (two strains), Hypoxylon investiens, Neoscytalidium sp. (two strains) and Penicillium rubens. These isolates were subjected to submerged fermentation in two culture media to obtain metabolic extracts. The extracts obtained were analyzed in terms of their absorbance between 400 and 700 nm. The pigmented extract produced by H. investiens in medium containing yeast extract showed maximum absorbance in the red absorption range (UA700 = 0.550) and significant antioxidant and antimicrobial activity. This isolate can thus be considered a new source of extracellular pigment.

Characterization and comprehensive analysis of the ecological interaction networks of bacterial communities in Paullinia cupana var. sorbilis by 16S rRNA gene metabarcoding.

Endophytes improve the host performance in areas of high plant endemicity. Paullinia cupana is an Amazonia plant species of economic and social importance due to the high caffeine concentration in its seeds. An interesting strategy to identify endophytic microorganisms with potential biotechnological application is to understand the factors that influence the endophytic community to rationalize the host management programs. We used the next-generation sequencing for bacterial 16S rRNA gene to examine how the P. cupana organ, genotype, and geographic location influenced its endophytic bacterial community. We obtained 1520 operational taxonomic units (OTUs) distributed in 19 phyla, 32 classes, 79 orders, 114 families and 174 genera. The P. cupana roots and leaves were specifically colonized by the bacterial genera Acidothermus and Porphyromonas, respectively, with high relative frequency. The plant organ type influenced the endophytic community's richness, diversity, OTUs composition, relative abundance of phyla and genera, and genera interaction network. However, the host plant genotype and geographic location influenced the composition and interaction among genera in the network analysis. Prevotella is a super-generalist genus in the interaction network of endophytic bacteria of P. cupana. This study revealed endophytic bacterial groups of importance to P. cupana and stressed that the host plant organ modulates the structure and interactions within this community. Our results indicated that the microbial community adapted to colonize P. cupana by adjusting to its composition and interaction network. The isolation of abundant and super-generalist bacterial genera shall help to examine their functionality to the composition and fitness of the endophytic community of P. cupana.

Diversity of cultivable bacterial endophytes in Paullinia cupana and their potential for plant growth promotion and phytopathogen control.

Endophytic bacteria occupy the same niche of phytopathogens and may produce metabolites that induce the host plant systemic resistance and growth. Host and environmental variables often determine the endophytic community's structure and composition. In this study, we addressed whether the plant genotype, organ, and geographic location influence the structure, composition, and functionality of endophytic bacterial communities in Paullinia cupana. To characterize the communities and identify strains with potential application in agriculture, we analyzed two P. cupana genotypes cultivated in two cities of the State of Amazonas, Brazil. Endophytic bacteria were isolated from surface-disinfested root, leaf, and seed tissues through the fragmentation and maceration techniques. The colonization rate, number of bacteria, richness, diversity, and functional traits were determined. The plant growth-promoting ability of selected bacterial strains was assessed in Sorghum bicolor. We identified 95 bacterial species distributed in 29 genera and 3 phyla (Proteobacteria, Actinobacteria, and Firmicutes). The colonization rate, richness, diversity, and species composition varied across the plant organs; the last parameter also varied across the plant genotype and location. Some strains exhibited relevant plant growth-promoting traits and antagonistic traits against the main phytopathogens of P. cupana, but they were not separated by functional traits. The main bacterial strains with plant growth-promoting traits induced S. bicolor growth. Altogether, our findings open opportunities to study the application of isolated endophytic bacterial strains in the bioprospection of processes and products.