HighlightPhytoplasma effector SAP11 modulates plant volatile organic compound emissions by suppressing the expression of NbOMT1, which encodes an O-methyltransferase required for the biosynthesis of 3-isobutyl-2-methoxypyrazine.

No abstract

Taiwania cryptomerioides is a monotypic gymnosperm species, valued for the high decay resistance of its wood. This durability has been attributed to the abundance of terpenoids, especially the major diterpenoid metabolite ferruginol, with antifungal and antitermite activity. Specialized diterpenoid metabolism in gymnosperms primarily recruits bifunctional class-I/II diterpene synthases (diTPSs), whereas monofunctional class-II and class-I enzymes operate in angiosperms. In this study, we identified a previously unrecognized group of monofunctional diTPSs in T. cryptomerioides, which suggests a distinct evolutionary divergence of the diTPS family in this species. Specifically, five monofunctional diTPS functions not previously observed in gymnosperms were characterized, including monofunctional class-II enzymes forming labda-13en-8-ol diphosphate (LPP, TcCPS2) and (+)-copalyl diphosphate (CPP, TcCPS4), and three class-I diTPSs producing biformene (TcKSL1), levopimaradiene (TcKSL3) and phyllocladanol (TcKSL5), respectively. Methyl jasmonate (MeJA) elicited the accumulation of levopimaradiene and the corresponding biosynthetic diTPS genes, TcCPS4 and TcKSL3, is consistent with a possible role in plant defense. Furthermore, TcCPS4 and TcKSL3 are likely to contribute to abietatriene biosynthesis via levopimaradiene as an intermediate in ferruginol biosynthesis in Taiwania. In conclusion, this study provides deeper insight into the functional landscape and molecular evolution of specialized diterpenoid metabolism in gymnosperms as a basis to better understand the role of these metabolites in tree chemical defense.

Amaranthus tricolor L., a vegetable Amaranthus species, is an economically important crop containing large amounts of betalains. Betalains are natural antioxidants and can be classified into betacyanins and betaxanthins, with red and yellow colors, respectively. A. tricolor cultivars with varying betalain contents, leading to striking red to green coloration, have been commercially produced. However, the molecular differences underlying betalain biosynthesis in various cultivars of A. tricolor remain largely unknown. In this study, A. tricolor cultivars with different colors were chosen for comparative transcriptome analysis. The elevated expression of AmCYP76AD1 in a red-leaf cultivar of A. tricolor was proposed to play a key role in producing red betalain pigments. The functions of AmCYP76AD1, AmDODAα1, AmDODAα2, and AmcDOPA5GT were also characterized through the heterologous engineering of betalain pigments in Nicotiana benthamiana. Moreover, high and low L-DOPA 4,5-dioxygenase activities of AmDODAα1 and AmDODAα2, respectively, were confirmed through in vitro enzymatic assays. Thus, comparative transcriptome analysis combined with functional and enzymatic studies allowed the construction of a core betalain biosynthesis pathway of A. tricolor. These results not only provide novel insights into betalain biosynthesis and evolution in A. tricolor but also provide a basal framework for examining genes related to betalain biosynthesis among different species of Amaranthaceae.

Antrodia cinnamomea is a precious edible mushroom endemic to Taiwan that has been claimed to have significant health promotion activities. Antrodia salmonea is a new species of the genus Antrodia. In this study, we compared the metabolites and bioactivity of A. cinnamomea and A. salmonea fruiting bodies. The volatiles of A. cinnamomea and A. salmonea were characterized and 3,4,5-trimethoxybenzaldehyde was found to be the most abundant compound in A. cinnamomea; the other abundant compounds were δ-guaiene, isolongifolene, 1-octen-3-ol, 4-terpinenol, α-guaiene, and p-cymene. In A. salmonea, the main volatiles were α-cedrene, 1-octen-3-ol, D-limonene, cadinadiene, germacrene D, isolongifolene, and α-muurolene. Furthermore, five ergostane-type triterpenoids and two lanostane-type triterpenoids were selected as index compounds characterizing A. cinnamomea and A. salmonea extracts. The content of each compound varied between the two species. (R,S)-antcin B was the most abundant compound in A. cinnamomea fruiting bodies (75.18 ± 0.11 µg/mg). However, (R,S)-antcin C (184.85 ± 0.96 µg/mg) was the major triterpenoid in the A. salmonea fruiting body. Furthermore, two compounds, antcin M and methyl antcinate K, were only present in the A. salmonea fingerprint; therefore, antcin M and methyl antcinate K may be important for distinguishing between A. cinnamomea and A. salmonea fruiting bodies. Finally, examination of anti-inflammation activity and cytotoxicity showed that A. salmonea had more anti-inflammatory activity than A. cinnamomea; however, A. salmonea was more cytotoxic than A. cinnamomea. In conclusion, the composition and bioactivity of the fruiting bodies of A. cinnamomea and A. salmonea varies. Therefore, it is recommended that further toxicological evaluation and investigation of the biological activity of A. salmonea is carried out to ensure its safe and efficacious use as an alternative to A. cinnamomea.