Geraniol is an acyclic monoterpene alcohol, which plays key roles in plant-environment interactions, such as pest repelling, antimicrobial activity, and pollinator attraction as well as the aroma traits for tea plants. It was reported that a cytosolic Nudix hydrolase (NUDX1) catalyzes geranyl pyrophosphate (GPP) into geranyl monophosphate (GP), followed by dephosphorylation with an endogenous phosphatase to produce geraniol. Two homologues of AtNUDX1 were found in tea genome (CsNUDX1-cyto and CsNUDX1-chlo) with different subcellular location. Searching the homologues of AtNUDX1 on Phytozome shows that fifty-eight plant species contain the homologues of AtNUDX1 (with identities>64%). However, no homologue of AtNUDX1 was found in the genomes of grass species, with the exception of Brachypodium distachyon. We thus detected AR2000-enzymed geraniol in fresh leaves of rice, wheat, maize, and tea plants. The results show that free geraniol was undetectable in fresh leaves of rice, wheat and maize, where as young shoots of four tea cultivars had high levels of geraniol (0.87-4.12 μg·g-1). Two CsNUDX1 genes were highly expressed in young tea leaves and had a positive correlation (above 0.7) with the accumulation of geraniol. This study shows that NUDX1s are widely present in plant genome, which are closely related to the formation of geraniol.
[1] He H, Bian G, Herbst-Gervasoni C J, et al. Discovery of the cryptic function of terpene cyclases as aromatic prenyltransferases[J]. Nature Communications, 2020, 11(1): 3958. doi: 10.1038/s41467-020-17642-2.
[2] Bian G, Deng Z, Liu T.Strategies for terpenoid overproduction and new terpenoid discovery[J]. Curr Opin Biotech, 2017, 48: 234-241.
[3] Aharoni A, Giri A P, Deuerlein S, et al.Terpenoid metabolism in wild-type and transgenic Arabidopsis plants[J]. Plant Cell, 2003, 15(12): 2866-2884.
[4] Dudareva N, Negre F, Nagegowda D A, et al.Plant volatiles: recent advances and future perspectives[J]. Critical Reviews in Plant Sciences, 2006, 25(5): 417-440.
[5] Zhao M Y, Zhang N, Gao T, et al.Sesquiterpene glucosylation mediated by glucosyltransferase UGT91Q2 is involved in the modulation of cold stress tolerance in tea plants[J]. New Phytologist, 2020, 226(2): 362-3720.
[6] Chen F, Tholl D, Bohlmann J, et al.The family of terpene synthases in plants: a mid-size family of genes for specialized metabolism that is highly diversified throughout the kingdom[J]. The Plant Journal, 2011, 66(1): 212-229.
[7] Gutensohn M, Orlova I, Nguyen T T, et al.Cytosolic monoterpene biosynthesis is supported by plastid-generated geranyl diphosphate substrate in transgenic tomato fruits[J]. The Plant Journal, 2013, 75(3): 351-363.
[8] Dong L, Miettinen K, Goedbloed M, et al.Characterization of two geraniol synthases from Valeriana Officinalis and Lippia Dulcis: similar activity but difference in subcellular localization[J]. Metabolic Engineering, 2013, 20: 198-211.
[9] Iijima Y, Gang D R, Fridman E, et al.Characterization of geraniol synthase from the peltate glands of sweet Basil[J]. Plant Physiol, 2004, 134(1): 370-379.
[10] Davidovich-Rikanati R, Sitrit Y, Tadmor Y, et al.Enrichment of tomato flavor by diversion of the early plastidial terpenoid pathway[J]. Natbiotechnol, 2007, 25(8): 899-901.
[11] Magnard J L, Roccia A, Caissard J C, et al.Biosynthesis of monoterpene scent compounds in roses[J]. Science, 2015, 349(6243): 81-83.
[12] Zhou H C, Wang S J, Xie H F, et al.Cytosolic Nudix Hydrolase 1 is involved in geranyl β-primeveroside production in tea[J]. Front Plant Sci, 2022, 13: 833682. doi: 10.3389/fpls.2022.833682.
[13] Wei C, Yang H, Wang S, et al.Draft genome sequence of Camellia sinensis var. sinensis provides insights into the evolution of the tea genome and tea quality[J]. Proc Natl Acad Sci, 2018, 115: E4151-E4158.
[14] Xia E, Tong W, Hou Y, et al.The reference genome of tea plant and resequencing of 81 diverse accessions provide insights into its genome evolution and adaptation[J]. Molecular Plant, 2020, 13(7): 1013-1026.
[15] Chen J D, Zheng C, Ma J Q, et al.The chromosome-scale genome reveals the evolution and diversification after the recent tetraploidization event in tea plant[J]. Hortic Res, 2020, 7: 63. doi: 10.1038/s41438-020-0288-2.
[16] Wang X C, Feng H, Chang Y X, et al.Population sequencing enhances understanding of tea plant evolution[J]. Nature Communications, 2020, 11(1): 4447. doi: 10.1038/s41467-020
-18228-8.
[17] Zhang Q J, Li W, Li K, et al.The chromosome-level reference genome of tea tree unveils recent bursts of non-autonomous LTR retrotransposons in driving genome size evolution[J]. Molecular Plant, 2020, 13(7): 935-938.
[18] Zhang W Y, Zhang H, Qiu Y, et al.Genome assembly of wild tea tree DASZ reveals pedigree and selection history of tea varieties[J]. Nature Communications, 2020, 11: 3719. doi: 10.1038/s41467-020-17498-6.
[19] Liu J, Guan Z Y, Liu H B, et al.Structural insights into the substrate recognition mechanism of Arabidopsis GPP-bound NUDX1 for noncanonical monoterpene biosynthesis[J]. Molecular Plant, 2018, 11(1): 218-221.
[20] Kraszewska E.The plant Nudix hydrolase family[J]. Acta Biochim Pol, 2008, 55(4): 663-671.
[21] McLennan A G. The Nudix hydrolase superfamily[J]. Cell Mol Life Sci, 2006, 63(2): 123-143.
[22] Wilson A E, Tian L.Phylogenomic analysis of UDP-dependent glycosyltransferases provides insights into the evolutionary landscape of glycosylation in plant metabolism[J]. The Plant Journal, 2019, 100(6): 1273-1288.
[23] Caputi L, Malnoy M, Goremykin V, et al.A genome-wide phylogenetic reconstruction of family 1 UDP-glycosyltransferases revealed the expansion of the family during the adaptation of plants to life on land[J]. The Plant Journal, 2012, 69(6): 1030-1042.
[24] Liu G F, Liu J J, He Z R, et al.Implementation of CsLIS/NES in linalool biosynthesis involves transcript splicing regulation in Camellia sinensis[J]. Plant Cell Environ, 2018, 41(1): 176-186.
[25] Wang M Q, Ma W J, Shi J, et al.Characterization of the key aroma compounds in Longjing tea using stir bar sorptive extraction (SBSE) combined with gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), odor activity value (OAV), and aroma recombination[J]. Food Research International, 2020, 130: 108908. doi: 10.1016/j.foodres.2019.108908.
[26] Wang H F, You X Q.Free and glycosidically bound monoterpene alcohols in Qimen black tea[J]. Food Chemistry, 1996, 56(4): 395-398.
[27] Zhu J, Chen F, Wang L, et al.Comparison of aroma-active volatiles in Oolong tea infusions using GC-Olfactometry, GC-FPD, and GC-MS[J]. Journal of Agricultural and Food Chemistry, 2015, 63(34): 7499-510.
[28] Yuan J S, Köllner T G, Wiggins G, et al.Molecular and genomic basis of volatile-mediated indirect defense against insects in rice[J]. The Plant Journal, 2008, 55(3): 491-503.
[29] Takeo T.Variation in amounts of linalool and geraniol produced in tea shoots by mechanical injury[J]. Phytochemistry, 1981, 20(9): 2149-2151.
浙公网安备 33019902000101号 
