Diurnal emission of herbivore-induced(Z)-3-hexenyl acetate and allo-ocimene activates sweet potato defense responses to sweet potato weevils

The sweet potato weevil(Cylas formicarius(Fab.)(Coleoptera: Brentidae)) is a pest that feeds on sweet potato(Ipomoea batatas(L.) Lam.(Solanales: Convolvulaceae)), causing substantial economic losses annually. However, no safe and effective methods have been found to protect sweet potato from this pest. Herbivore-induced plant volatiles(HIPVs)promote various defensive bioactivities, but their formation and the defense mechanisms in sweet potato have not been investigated. To identify the defensive HIPVs in sweet potato, the release dynamics of volatiles was monitored.The biosynthetic pathways and regulatory factors of the candidate HIPVs were revealed via stable isotope tracing and analyses at the transcriptional and metabolic levels. Finally, the anti-insect activities and the defense mechanisms of the gaseous candidates were evaluated. The production of(Z)-3-hexenyl acetate(z3HAC) and allo-ocimene was induced by sweet potato weevil feeding, with a distinct circadian rhythm. Ipomoea batatas ocimene synthase(IbOS) is first reported here as a key gene in allo-ocimene synthesis. Insect-induced wounding promoted the production of the substrate,(Z)-3-hexenol, and upregulated the expression of IbOS, which resulted in higher contents of z3HAC and allo-ocimene,respectively. Gaseous z3HAC and allo-ocimene primed nearby plants to defend themselves against sweet potato weevils. These results provide important data regarding the formation, regulation, and signal transduction mechanisms of defensive volatiles in sweet potato, with potential implications for improving sweet potato weevil management strategies.

Parahellenia,a new genus segregated from Hellenia(Costaceae)based on phylogenetic and morphological evidence

Previous studies recognized three major lineages of the family Costaceae:a South American clade,an Asian clade and a Costus clade.However,the genus Hellenia within the Asian clade has been shown to be non-monophyletic and its morphology has not been studied carefully.Therefore,the complete plastid genomes of Hellenia species were obtained and the monophyly of Hellenia was tested through four different datasets in this study.Plastid phylogenomic analyses of Costaceae revealed that Hellenia is strongly supported as paraphyletic.Two major clades are recovered,namely the Hellenia s.s.subclade and the Parahellenia subclade.Phylogenetic analyses based on an enlarged taxon sampling of the Asian clade using a two chloroplast markers dataset(trnK intron and trnL-F spacer)confirmed the paraphyly of Hellenia.Meanwhile,morphological analyses suggested that members of the Parahellenia subclade differ from the remaining Hellenia species in many characters including inflorescences,bracts,stigma,axillary buds,floral tubes and labellum.According to the present molecular and morphological evidence,the latter subclade is recognized as a new genus,Parahellenia.Two new species are described,four new combinations are made,and identification keys are also provided.

Star fruit extract and C-glycosylated flavonoid components have potential to prevent air pollutant-induced skin inflammation and premature aging

Air pollution adversely affects skin,leading to skin inflammation and premature skin aging.Plant derived antioxidant compounds have been considered to be promising in discovery of effective agents for the protection of skin from the damage by air pollutants.Our previous studies demonstrated that Averrhoa carambola fruit(known as star fruit)is rich in flavonoid C-glycosides with unique structures and potent antioxidant activity.Thus,the star fruit extract(SFE)and main flavonoid C-glycoside components,carambolasides I,J,and P(1-3),carambolaflavone B(4),and isovitexin 2″-O-α-l-rhamnoside(5),were investigated for the activity against air pollutant stress in human epidermis.As a result,SFE and compounds 1-5 exhibited significant inhibitory activity against protein carbonylation in oxidative-stressed stratum corneum with the best activity being shown by compound 3.SFE and compounds 2-5 were also active against engine exhaust-induced protein carbonylation in stratum corneum.When further evaluated,SFE and com-pound 3 significantly inhibited gene expression of the key inflammation mediators IL-1αand COX-2 in PM-stressed keratinocytes.The results indicated that SFE and the flavonoid C-glycosides are potentially effective against air pollutant-induced skin inflammation and premature aging.

Bioactive Diarylheptanoids from Alpinia coriandriodora

Eight new diarylheptanoids,coriandralpinins A-H(1-8),were isolated from the rhizomes of Alpinia coriandriodora,an edible plant of the ginger family.Their structures,including the absolute configurations,were established by extensive spectroscopic analysis and ECD calculations.Compounds 1-8 have a 1,5-O-bridged diarylheptanoid structure featuring polyoxygenated aryl units.When evaluated for intracellular antioxidant activity using t-BHP stressed RAW264.7 mac-rophages,all these compounds scavenged reactive oxygen species(ROS)in a concentration-dependent manner.Compounds 3 and 5 also showed inhibitory activity against NO release in LPS-induced RAW 264.7 cells.Six known flavonols,7,4′-di-O-methylkaempferol,7-O-methylquercetin,7,4′-di-O-methylquercetin,7,3′,4′-tri-O-methylquercetin,kaempferol 3-O-β-d-(6-O-α-l-rhamnopyranosyl)glucopyranoside,and 3-O-β-d-glucopyranuronosylquercetin were also isolated and characterized from the rhizomes.