The phytochemical properties, pharmacological effects and traditional uses of Actinidia eriantha Benth.: A review

RNA-Seq Analysis Reveals Potential Genes Involved in Plant Growth Regulator-Induced Ovary Development in Male Kiwifruit (Actinidia eriantha)

Kiwifruit is a dioecious woody liana fruit tree, and the non-fruitfulness of male plants leads to a great deal of blindness in the selection of male plants in crossbreeding. In this study, we induced the development of male plant ovary by externally applying plant growth regulators (PGRs) and performed histological observation, phytohormone content determination and transcriptome analysis on the abortive ovary of the male kiwifruit (Con), the ovary of the female kiwifruit (Fem) and the PGR-induced developing ovary of the male kiwifruit (PT). Histological analysis showed that the Con ovary was devoid of ovules and the carpels were atrophied, the Fem ovary had ovules and the PT ovary was devoid of ovules, but the carpels developed normally and were not atrophied. Endogenous phytohormone content measurements displayed higher levels of trans-zeatin (tZT) in PT and Fem than Con, and lower levels of gibberellin (GA3) and abscisic acid (ABA) than Con. Transcriptome analysis revealed significant differences in many key genes in the cytokinin and auxin pathways, which were consistent with the results of phytohormone content measurements. Meanwhile, the genes related to carpel development, SPT (DTZ79_04g03580) and SK41 (DTZ79_19g04340), were highly expressed in PT, suggesting that they may play a key role in PGR-induced development of the ovary in male kiwifruit. These results provide information for elucidating the potential regulatory network of PGR-induced ovary development in male flowers and contribute to further identification of valuable target genes.

Discovery and Functional Identification of 2,3-Oxidosqualene Cyclases and Cytochrome P450s in Triterpenoid Metabolic Pathways of Actinidia eriantha

Actinidia eriantha Benth, known as the "king of fruits", is rich in triterpenoid compounds, particularly ursane-type and oleanane-type triterpenic acids. These secondary metabolites have been widely applied in medicine, cosmetics, agriculture, and other fields. To date, key enzyme genes involved in triterpenoid metabolic pathways in A. eriantha remain unexplored. This study employed transcriptome sequencing analysis combined with synthetic biology approaches involving heterologous expression in yeast to identify crucial genes responsible for the biosynthesis of triterpenoid components in A. eriantha: Two 2,3-oxidosqualene cyclases (AeOSC2 and AeOSC3) were characterized to catalyze the formation of major triterpene scaffolds, α-amyrin [precursor of ursolic acid (UA)], β-amyrin [precursor of oleanolic acid (OA)], and ψ-taraxasterol, and two cytochrome P450s (AeCYP716A8 and AeCYP716A9) mediating three-step oxidation at the C-28 position of ursane-type and oleanane-type triterpene scaffolds to form UA, OA, and intermediate oxidation products. We successfully reconstructed the biosynthetic pathway of ursane- and oleanane-type triterpenoids from A. eriantha in a heterologous yeast host and elucidated the two-step enzymatic reactions involved in triterpenoid biosynthesis. These findings lay the foundation for further understanding the biosynthesis of key active components in A. eriantha.

Phytochemicals and Their Usefulness in the Maintenance of Health

Inflammation is the immune system's first biological response to infection, injury, or irritation. Evidence suggests that the anti-inflammatory effect is mediated by the regulation of various inflammatory cytokines, such as nitric oxide, interleukins, tumor necrosis factor alpha-α, interferon gamma-γ, as well as the non-cytokine mediator, prostaglandin E2. Currently, the mechanism of action and clinical usefulness of phytochemicals is known; their action on the activity of cytokines, free radicals, and oxidative stress. The latter are of great relevance in the development of diseases, such that the evidence collected demonstrates the beneficial effects of phytochemicals in maintaining health. Epidemiological evidence indicates that regular consumption of fruits and vegetables is related to a low risk of developing cancer and other chronic diseases.