Jozwiak Adam, Ples Magdalena, Skorupinska-Tudek Karolina, Kania Magdalena, Dydak Marta, Danikiewicz Witold, Swiezewska Ewa
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland.
Biochim Biophys Acta. 2013 Feb;1831(2):438-47. doi: 10.1016/j.bbalip.2012.11.006. Epub 2012 Nov 22.
Sugars are recognized as signaling molecules regulating the biosynthesis of secondary metabolites in plants. Here, a modulatory effect of sugars on dolichol and phytosterol profiles was noted in the hairy roots of Arabidopsis thaliana. Arabidopsis roots contain a complex dolichol mixture comprising three groups ('families') of dolichols differing in the chain-length. These dolichols, especially the longest ones are accompanied by considerable amounts of polyprenols of the same length. The spectrum of polyisoprenoid alcohols, i.e. dolichols and polyprenols, was dependent on sugar type (glucose or sucrose) and its concentration in the medium. Among the long-chain dolichols Dol/Pren-20 (dolichol or prenol molecule composed of 20 isoprene residues) and Dol/Pren-23 were the main components at 0.5% and 2% glucose, respectively. Moreover, the ratio of polyprenols versus respective dolichols was also modulated by sugar in this group of polyisoprenoids, with polyprenols dominating at 3% sucrose and dolichols at 2% glucose. Glucose concentration affected the expression level of genes encoding cis-prenyltransferases, enzymes responsible for elongation of the polyisoprenoid chain. The most abundant phytosterols of the A. thaliana roots, β-sitosterol, stigmasterol and campesterol, were accompanied by corresponding stanols and traces of brassicasterol, stigmast-4,22-dien-3-one and stigmast-4-en-3-one. Similar to the polyisoprenoids, sterol profile responded to the sugar present in the medium, β-sitosterol dominating in roots grown on 3% or lower glucose concentrations and stigmasterol in 3% sucrose. These results indicate an involvement of sugar signaling in the regulation of cis-prenyltransferases and phytosterol pathway enzymes.
糖类被认为是调节植物次生代谢物生物合成的信号分子。在此，在拟南芥毛状根中发现了糖类对多萜醇和植物甾醇谱的调节作用。拟南芥根含有复杂的多萜醇混合物，由链长不同的三类（“家族”）多萜醇组成。这些多萜醇，尤其是最长链的多萜醇，伴随着相当数量的相同长度的聚异戊二烯醇。聚异戊二烯醇（即多萜醇和聚异戊二烯醇）的谱取决于糖类类型（葡萄糖或蔗糖）及其在培养基中的浓度。在长链多萜醇中，Dol/Pren-20（由20个异戊二烯残基组成的多萜醇或聚异戊二烯醇分子）和Dol/Pren-23分别是0.5%葡萄糖和2%葡萄糖条件下的主要成分。此外，在这组聚异戊二烯醇中，糖类也调节了聚异戊二烯醇与相应多萜醇的比例，在3%蔗糖条件下聚异戊二烯醇占主导，在2%葡萄糖条件下多萜醇占主导。葡萄糖浓度影响编码顺式异戊烯基转移酶（负责聚异戊二烯链延长的酶）的基因的表达水平。拟南芥根中最丰富的植物甾醇，β-谷甾醇、豆甾醇和菜油甾醇，伴随着相应的甾烷醇以及痕量的油菜甾醇、豆甾-4,22-二烯-3-酮和豆甾-4-烯-3-酮。与聚异戊二烯醇类似，甾醇谱对培养基中存在的糖类有响应，β-谷甾醇在葡萄糖浓度为3%或更低的根中占主导，豆甾醇在3%蔗糖条件下占主导。这些结果表明糖类信号参与了顺式异戊烯基转移酶和植物甾醇途径酶的调节。
