Abstract

Effect of synthetic analogs of auxins—2.4-dichlorophenoxyacetic (2.4-D) and α-naphthylacetic (α-NAA) acids—on growth characteristics and accumulation of steroidal glycosides was investigated in suspension cell culture of Tribulus terrestris L. It was found that the substitution of α-NAA for 2.4-D in the nutrient medium brought about a rise in the content of steroidal glycosides in the cultured cells (up to six times) and broadened their structural diversity (nine identified oligofurostanosides when growing culture on the medium with α-NAA vs. five compounds on the medium with 2.4-D). Positive influence of α-NAA exerted on biosynthetic characteristics of T. terrestris suspension cell culture was accompanied by changes in cell morphology (cytodifferentiation), the extent of their aggregation, and gradual decrease (during 3–4 cycles of growing) in culture viability up to its extinction. Simultaneous presence of both synthetic analogs of auxins (α-NAA and 2.4-D) in the growing medium also caused a rise in the content of steroidal glycosides in the cells of T. terrestris, although it was less pronounced (up to three times); however, the culture showed a relatively steady growth and great viability in this case. It was concluded that these two auxin analogs differently influenced the growth of plants’ cells in vitro and biosynthesis of substances of specialized metabolism, 2.4-D promoted cell proliferation, whereas α-NAA induced cytodifferentiation and activated the production of secondary compounds. This conclusion is corroborated by the data concerning plant cell cultures of other species of medicinal plants accumulating secondary metabolites from other groups. For instance, in the experiments with suspension cell culture of Panax ginseng C.A. Mey., substitution in the growth medium of α-NAA for 2.4-D brought about a rise in the content and diversity of triterpene glycosides (ginsenosides) associated with an elevated cell aggregation and deterioration of culture’s viability. Comparison of production of steroidal glycosides in plant cell cultures of T. terrestris and Dioscorea deltoidea Wall. that is grown for more than 40 years has shown that both cultures accumulated only furostanol (rather than spirostanol) glycosides that promoted cell proliferation. In suspension cell culture of Dioscorea, a high level of oligofurostanosides (up to 12% of dry biomass) was accumulated when growing culture on the medium with 2.4-D. Thus, investigation into the production of furostanol glycosides in plant cultured cells points to a multifactor system of regulation of secondary metabolism in vitro. Different synthetic auxin analogs may exert alternative influences on growth and biosynthetic processes. At the same time, prolonged culturing leads to an autoselection of cells with the properties promoting proliferation, specifically, with a high content of furostanol glycosides.

中文翻译：

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合成生长素类似物（2.4-D和α-NAA）对ter藜悬浮细胞生长和生物合成特性的影响。

摘要

的生长素-2.4二氯苯氧（2.4-d）和α-萘乙酸（α-NAA）羧酸上的生长特性与甾体糖苷的积累在悬浮细胞培养研究了合成的类似物的效果蒺藜L.结果发现，该在营养培养基中将α-NAA替换为2.4-D导致培养细胞中甾体糖苷含量增加（最多六倍），并拓宽了其结构多样性（当在含有α的培养基上培养时，九种已鉴定的寡聚呋喃糖苷-NAA与含有2.4-D的培养基上的五种化合物）。α-NAA的积极影响施加的生物合成特性T.蒺藜悬浮细胞培养伴随着细胞形态的变化（细胞分化），它们的聚集程度以及直至消失的培养活力的逐渐降低（在3–4个生长周期中）。生长素中两种生长素的合成类似物（α-NAA和2.4-D）的同时存在也导致了藜麦中甾体糖苷含量的增加。，尽管发音不明显（最多3次）；然而，在这种情况下，培养物显示出相对稳定的生长和巨大的生存能力。结论是，这两种生长素类似物在体外影响植物细胞的生长和专门代谢物质的生物合成方面不同，2.4-D促进细胞增殖，而α-NAA诱导细胞分化并激活次要化合物的产生。有关其他药用植物的植物细胞培养物中积累了其他族群次生代谢产物的数据证实了这一结论。例如，在人参悬浮细胞培养实验中CA Mey。，用α-NAA的生长培养基替代2.4-D，导致三萜糖苷（人参皂苷）的含量和多样性增加，这与细胞聚集增加和培养物活力降低有关。T. terrestris和Dioscorea deltoidea Wall的植物细胞培养物中甾体糖苷生产的比较。生长超过40年的结果表明，两种培养物仅积聚促进细胞增殖的呋喃甾醇（而不是螺固醇）糖苷。薯suspension悬浮细胞培养当在带有2.4-D的培养基上培养时，会积聚高水平的寡呋喃果糖苷（占干生物质的12％）。因此，对植物培养细胞中呋喃甾醇糖苷生产的研究指出了体外二级代谢调节的多因素系统。不同的合成生长素类似物可能对生长和生物合成过程产生替代性影响。同时，长时间的培养导致细胞的自选具有促进增殖的特性，特别是具有高含量的呋喃甾醇糖苷。