Multicellular compartmentation of Catharanthus roseus alkaloid biosynthesis predicts intercellular translocation of a pathway intermediate
Multicellular compartmentation of Catharanthus roseus alkaloid biosynthesis predicts intercellular translocation of a pathway intermediate
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DOI：
10.1105/tpc.11.5.887
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发表时间：
1999-05-01
期刊：
影响因子：
11.6
通讯作者：
De Luca, V
中科院分区：
文献类型：
--
作者：
St-Pierre, B;Vazquez-Flota, FA;De Luca, V
采用原位RNA杂交和免疫细胞化学方法，建立了马达加斯加长春花（Catharanthus roseus）单萜类吲哚生物碱生物合成的细胞分布。定位了参与中心中间体strictosidine生物合成的色氨酸脱羧酶（TDC）和strictosidine合成酶（STR1），以及参与vindoline生物合成末端步骤的去乙酰氧基vindoline 4-羟化酶（D4H）和去乙酰vindoline 4- o -乙酰转移酶（DAT）。tdc和str1 mrna主要存在于茎、叶和花蕾的表皮，而它们主要存在于根尖顶端分生组织周围的原皮细胞和皮层细胞中。相比之下，d4h和dat mrna与叶、茎和花蕾的乳汁管和异母细胞相关。TDC、D4H和DAT蛋白的免疫细胞化学定位证实了vindoline生物合成早期和晚期的差异定位。因此，我们得出结论，主要的叶子生物碱的加工涉及至少两种细胞类型的参与，并且需要一个途径中间体的细胞间易位。原位RNA杂交研究和解剖叶片的互补研究也显示了这四个基因在成熟叶片中的基向表达梯度，这表明vindoline途径的表达在叶片早期发育过程中是短暂的。这些结果部分解释了为什么用细胞培养技术生产vindoline的尝试失败了。
In situ RNA hybridization and immunocytochemistry were used to establish the cellular distribution of monoterpenoid indole alkaloid biosynthesis in Madagascar periwinkle (Catharanthus roseus). Tryptophan decarboxylase (TDC) and strictosidine synthase (STR1), which are involved in the biosynthesis of the central intermediate strictosidine, and desacetoxyvindoline 4-hydroxylase (D4H) and deacetylvindoline 4-O-acetyltransferase (DAT), which are involved in the terminal steps of vindoline biosynthesis, were localized. tdc and str1 mRNAs were present in the epidermis of stems, leaves, and flower buds, whereas they appeared in most protoderm and cortical cells around the apical meristem of root tips. In marked contrast, d4h and dat mRNAs were associated with the laticifer and idioblast cells of leaves, stems, and flower buds. Immunocytochemical localization for TDC, D4H, and DAT proteins confirmed the differential localization of early and late stages of vindoline biosynthesis. Therefore, we concluded that the elaboration of the major leaf alkaloids involves the participation of at least two cell types and requires the intercellular translocation of a pathway intermediate. A basipetal gradient of expression in maturing leaves also was shown for all four genes by in situ RNA hybridization studies and by complementary studies with dissected leaves, suggesting that expression of the vindoline pathway occurs transiently during early leaf development. These results partially explain why attempts to produce vindoline by cell culture technology have failed.