Transcriptome and metabolome analyses provide insights into the relevance of pericarp thickness variations in Camellia drupifera and Camellia oleifera

Camellia fruit is a woody edible oil source with a recalcitrant pericarp, which increases processing costs. However, the relevance of pericarp thickness variations in Camellia species remains unclear. Therefore, this study aimed to identify pericarp differences at the metabolic and transcription levels between thick-pericarp Camellia drupifera BG and thin-pericarp Camellia oleifera SG. Forty differentially accumulated metabolites were screened through non-targeted UHPLC-Q-TOF MS-based metabolite profiling. S-lignin was prominently upregulated in BG compared with SG, contributing to the thick pericarp of BG. KEGG enrichment and coexpression network analysis showed 29 differentially expressed genes associated with the lignin biosynthetic pathway, including 21 genes encoding catalysts and 8 encoding transcription factors. Nine upregulated genes encoding catalysts potentially led to S-lignin accumulation in BG pericarp, and transcription factors NAC and MYB were possibly involved in major transcriptional regulatory mechanisms. Conventional growth-related factors WRKYs and AP2/ERFs were positively associated while pathogenesis-related proteins MLP328 and NCS2 were negatively associated with S-lignin content. Thus, Camellia balances growth and defense possibly by altering lignin biosynthesis. The results of this study may guide the genetic modifications of C. drupifera to optimize its growth-defense balance and improve seed accessibility.

Comprehensive evaluation of chemical composition and health-promoting effects with chemometrics analysis of plant derived edible oils

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22 edible oils can be discriminated based on tocopherol and phytosterol contents.

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In vitro antioxidant activity is correlated to polyphenol, tocopherol, and squalene.

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Oxidative and heat stress resistance is correlated to tocopherol and phytosterol.

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In vivo antioxidant activity is correlated to polyphenol, squalene, MUFA and PUFA.

In the last decade, with a growing emphasis on healthy diets, functional edible oils with high nutritional quality are becoming increasingly popular around the world. This study systematically compared the chemical composition and protective effect of 22 vegetable oils using multivariate chemometric tools. The results showed that the fatty acid composition and minor compounds were extremely variable among tested oils. Hierarchical cluster and principal component analysis discriminated these oils according to the tocopherol and phytosterol contents. The Pearson’s correlation analysis indicated that in vitro radical scavenging capacity was significantly correlated to polyphenol, tocopherol, and squalene. Additionally, the ameliorate effects on the heat and oxidative stress, ROS contents, and antioxidant enzyme activities were measured in Caenorhabditis elegans. The results showed that the antioxidant activity and stress resistance were positively correlated to polyphenol, tocopherol, phytosterol, MUFA, and PUFA, respectively. This study may offer an insight into oil discrimination and functional oil exploitation.

Bioactive Compound Profiling of Olive Fruit: The Contribution of Genotype

The health, therapeutic, and organoleptic characteristics of olive oil depend on functional bioactive compounds, such as phenols, tocopherols, squalene, and sterols. Genotype plays a key role in the diversity and concentration of secondary compounds peculiar to olive. In this study, the most important bioactive compounds of olive fruit were studied in numerous international olive cultivars during two consecutive seasons. A large variability was measured for each studied metabolite in all 61 olive cultivars. Total phenol content varied on a scale of 1–10 (3831–39,252 mg kg−1) in the studied cultivars. Squalene values fluctuated over an even wider range (1–15), with values of 274 to 4351 mg kg−1. Total sterols ranged from 119 to 969 mg kg−1, and total tocopherols varied from 135 to 579 mg kg−1 in fruit pulp. In the present study, the linkage among the most important quality traits highlighted the scarcity of cultivars with high content of at least three traits together. This work provided sound information on the fruit metabolite profile of a wide range of cultivars, which will facilitate the studies on the genomic regulation of plant metabolites and development of new olive genotypes through genomics-assisted breeding.