Untargeted Metabolomic Analysis of Leaves and Roots of Jatropha curcas Genotypes with Contrasting Levels of Phorbol Esters.

AIMS: Phorbol esters (PE) are toxic diterpenoids accumulated in physic nut (Jatropha curcas L.) seed tissues. Their biosynthetic pathway remains unknown, and the participation of roots in this process may be possible. Thus, we set out to study the deposition pattern of PE and other terpenoids in roots and leaves of genotypes with detected (DPE) and not detected (NPE) phorbol esters based on previous studies. OUTLINE OF DATA RESOURCES: We analyzed physic nut leaf and root organic extracts using LC-HRMS. By an untargeted metabolomics approach, it was possible to annotate 496 and 146 metabolites in the positive and negative electrospray ionization modes, respectively. KEY RESULTS: PE were detected only in samples of the DPE genotype. Remarkably, PE were found in both leaves and roots, making this study the first report of PE in J. curcas roots. Furthermore, untargeted metabolomic analysis revealed that diterpenoids and apocarotenoids are preferentially accumulated in the DPE genotype in comparison with NPE, which may be linked to the divergence between the genotypes concerning PE biosynthesis, since sesquiterpenoids showed greater abundance in the NPE. UTILITY OF THE RESOURCE: The LC-HRMS files, publicly available in the MassIVE database (identifier MSV000092920), are valuable as they expand our understanding of PE biosynthesis, which can assist in the development of molecular strategies to reduce PE levels in toxic genotypes, making possible the food use of the seedcake, as well as its potential to contain high-quality spectral information about several other metabolites that may possess biological activity.

Proteomic changes associated with the development of açaí (Euterpe oleracea Mart.) seeds.

Açaí palm (Euterpe oleracea Mart.) seeds are a rich source of mannans, which can be used to generate bioethanol or be converted to high-value D-mannose, in addition to being a source of polyphenols with beneficial health properties. Here, we present a quantitative proteome dataset of açaí seeds at four stages of development (S1, S2, S3, and S4 stages), in which 2465 high confidence proteins were identified and 524 of them show statistically different abundance profiles during development. Several enzymes involved in the biosynthesis of nucleotide-sugars were quantified, especially those dedicated to the formation of GDP-mannose, which showed an increase in abundance between stages S1 and S3. Our data suggest that linear mannans found abundantly in endosperm cell walls are initially deposited as galactomannans, and during development lose the galactosyl groups. Two isoforms of alpha-galactosidase enzymes showed significantly increased abundances in the S3 and S4 stages. Additionally, we quantified the enzymes participating in the central pathway of flavonoid biosynthesis responsible for the formation of catechin and epicatechin, which are subunits of procyanidins, the main class of polyphenols in the açaí seeds. These proteins showed the same pattern of deposition, in which higher abundances were seen in the S1 and S2 stages.

Phenolic Profile and Antioxidant Properties in Extracts of Developing Açaí (Euterpe oleracea Mart.) Seeds.

We investigated changes in the phenolic profile and antioxidant properties in the extracts of developing seeds of açaí (Euterpe oleracea). Four developmental stages were evaluated, with earlier stages displaying higher antioxidant activity and polyphenols content, while mass spectrometry analysis identified procyanidins (PCs) as the major components of the extracts in all stages. B-type PCs varied from dimers to decamers, with A-type linkages in a smaller number. Extracted PCs decreased in average length from 20.5 to 10.1 along seed development. PC composition indicated that (-)-epicatechin corresponded to over 95% of extension units in all stages, while (+)-catechin presence as the starter unit increased from 42 to 78.8% during seed development. This variation was correlated to the abundance of key enzymes for PC biosynthesis during seed development. This study is the first to report PC content and composition variations during açaí seed development, which can contribute to studies on the plant's physiology and biotechnological applications.

Proteome Dynamics of the Developing Açaí Berry Pericarp (Euterpe oleracea Mart.).

Quantitative proteome analysis of four developmental stages of pericarp tissues of the açaí berry (Euterpe oleracea Mart.) was performed by the isobaric labeling of peptides with iTRAQ 4-plex, hydrophilic interaction liquid chromatography pre-fractionation of labeled peptides, and high-performance mass spectrometry analysis. This analysis resulted in the identification of 4286 proteins, of which 476 presented differential abundance between the stages. The differential abundance of these proteins was seen to be coordinated with the metabolic demands during cell division, lignification, and cell expansion at developmental stages 1 and 2 as well as phenolic acid accumulation and metabolic changes in the fruit maturation at developmental stages 3 and 4. The distinct accumulation of anthocyanins observed in the pericarp at developmental stage 4 was correlated with the increase in abundance of some key biosynthetic enzymes, such as leucoanthocyanidin dioxygenase, anthocyanidin O-3-glycosyltransferase, and UDP-glycosyltransferase. Here, evidence is also provided for the presence in the açaí berry of secondary metabolites not previously described in açaí, such as pterostilbene, matairesinol, and furaneol. Together, these results will pave the way for studies aimed at the genetic improvement of the nutritional properties of this important fruit crop.