不同浓度硒对烟草根系形态、生长素含量及相关基因表达的影响

Effects of selenium at different concentrations on root morphology, auxin content and auxin-related gene expression in tobacco

为明确施用不同质量浓度硒对烟草根系形态、生长素含量及生长素相关基因表达量的影响,在人工培养箱中(光强300μmol·m^-2·s^-1,28℃/16h昼,24℃/8h夜)以DR5::GUS云烟87转基因烟草(纯合株系)为供试材料进行烟苗培育,并测定了不同浓度硒处理(培养基硒浓度0、1、5、10和20mg/L)的烟草根系生物量、根长、侧根数、MDA含量(质量分数)、生长素含量(质量分数)、生长素合成限速酶NtYUCCA编码基因以及生长素极性运输蛋白NtPINs基因家族表达量。结果表明:硒对烟草的生长发育具有双重效应。低浓度硒(1mg/L)处理条件下,生长素合成NtYUCCA基因家族与生长素极性运输蛋白NtPINs基因家族的表达水平提高,GUS活性增强,根系生长素含量增加,烟草生物量显著提高,根系构型发生改变(主根伸长,侧根数量多),MDA含量降低,抗氧化能力增强,进而促进了烟草的生长发育;高浓度硒(10mg/L)处理条件下,生长素含量降低,GUS活性减弱,烟草的生长发育受到抑制。

In order to clarify the effects of selenium (Se) at different concentrations on root morphology, auxin contents and auxin-related gene expressions, an artificial climate incubator with light intensity of 300 μmol·m^-2· s^-1, 28 ℃/16 h in the day and 24 ℃/8 h in the evening was used to plant tobacco seedlings (homozygous DR5::GUS transgenic line, Yunyan 87). The root biomass, root length, lateral root number, MDA and auxin contents and the expression levels of NtYUCCA (a rate-limiting enzyme in auxin synthesis) and NtPIN (an auxin polar transport protein) gene families in transgenic tobacco were analyzed under Se treatments at concentrations of 0, 1, 5, 10 and 20 mg/L. The results showed that Se had double effects on tobacco growing. At low Se concentration (1 mg/L), the expression levels of NtYUCCA and NtPIN gene families, GUS activity, auxin content in root, biomass of tobacco plants, taproot length, lateral root number and antioxidant capacity increased, while MDA content decreased,indicating that the growing and development of tobacco were promoted. At high Se concentration (10 mg/L), auxin content and GUS activity reduced, suggesting that the growing and development of tobacco were inhibited.