Departamento de Ingeniería y Ciencias Agrarias, Área de Fisiología Vegetal, Universidad de León, 24071, León, Spain.
Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Nacional Andrés Bello, 8370146, Santiago, Chile.
Planta. 2018 Apr;247(4):987-999. doi: 10.1007/s00425-018-2840-y. Epub 2018 Jan 12.
Ancymidol inhibits the incorporation of cellulose into cell walls of maize cell cultures in a gibberellin-independent manner, impairing cell growth; the reduction in the cellulose content is compensated with xylans. Ancymidol is a plant growth retardant which impairs gibberellin biosynthesis. It has been reported to inhibit cellulose synthesis by tobacco cells, based on its cell-malforming effects. To ascertain the putative role of ancymidol as a cellulose biosynthesis inhibitor, we conducted a biochemical study of its effect on cell growth and cell wall metabolism in maize cultured cells. Ancymidol concentrations ≤ 500 µM progressively reduced cell growth and induced globular cell shape without affecting cell viability. However, cell growth and viability were strongly reduced by ancymidol concentrations ≥ 1.5 mM. The I value for the effect of ancymidol on FW gain was 658 µM. A reversal of the inhibitory effects on cell growth was observed when 500 µM ancymidol-treated cultures were supplemented with 100 µM GA. Ancymidol impaired the accumulation of cellulose in cell walls, as monitored by FTIR spectroscopy. Cells treated with 500 µM ancymidol showed a ~ 60% reduction in cellulose content, with no further change as the ancymidol concentration increased. Cellulose content was partially restored by 100 µM GA. Radiolabeling experiments confirmed that ancymidol reduced the incorporation of [C]glucose into α-cellulose and this reduction was not reverted by the simultaneous application of GA. RT-PCR analysis indicated that the cellulose biosynthesis inhibition caused by ancymidol is not related to a downregulation of ZmCesA gene expression. Additionally, ancymidol treatment increased the incorporation of [H]arabinose into a hemicellulose-enriched fraction, and up-regulated ZmIRX9 and ZmIRX10L gene expression, indicating an enhancement in the biosynthesis of arabinoxylans as a compensatory response to cellulose reduction.
Ancymidol 以赤霉素非依赖的方式抑制玉米细胞培养物细胞壁中纤维素的掺入，从而损害细胞生长；通过木聚糖来补偿纤维素含量的减少。Ancymidol 是一种植物生长延缓剂，可损害赤霉素的生物合成。据报道，它通过其对细胞形态的影响抑制烟草细胞中的纤维素合成。为了确定 ancymidol 作为纤维素生物合成抑制剂的可能作用，我们对其在玉米培养细胞中的细胞生长和细胞壁代谢中的作用进行了生化研究。浓度≤500μM 的 ancymidol 逐渐降低细胞生长并诱导球形细胞形态，而不影响细胞活力。然而，浓度≥1.5mM 的 ancymidol 强烈降低细胞生长和活力。ancymidol 对 FW 增益的影响的 I 值为 658μM。当用 100μM GA 补充 500μM ancymidol 处理的培养物时，观察到对细胞生长的抑制作用的逆转。FTIR 光谱监测表明，ancymidol 损害细胞壁中纤维素的积累。用 500μM ancymidol 处理的细胞显示纤维素含量降低约 60%，随着 ancymidol 浓度的增加，没有进一步变化。100μM GA 部分恢复纤维素含量。放射性标记实验证实 ancymidol 降低了 [C]葡萄糖掺入α-纤维素的量，并且这种降低不能通过同时施加 GA 来逆转。RT-PCR 分析表明，ancymidol 引起的纤维素生物合成抑制与 ZmCesA 基因表达的下调无关。此外，ancymidol 处理增加了 [H]阿拉伯糖掺入富含半纤维素的部分，并且上调了 ZmIRX9 和 ZmIRX10L 基因表达，表明阿拉伯木聚糖生物合成的增强是作为纤维素减少的补偿反应。
