硝酸银对‘凤丹’牡丹愈伤组织褐变过程中酚类物质合成及相关基因表达的影响

Effects of Silver Nitrate on the Synthesis of Phenolic Compounds and the Expression Levels of Related Genes in Callus Browning Process of Paeonia ostii 'Fengdan'

以‘凤丹’牡丹的组培苗为材料,在含有0-5.0 mg/L硝酸银的基础培养基中进行培养后,通过测量总酚含量、单体酚种类及其含量的变化和相关基因的表达情况,确定不同浓度的硝酸银对抑制愈伤组织褐化的作用。结果表明,培养基中加入硝酸银能够抑制相关基因的表达,明显降低愈伤组织中多酚类物质的含量进而减轻植物组织褐变程度,其中2.0 mg/L的综合效果最好;硝酸银对组培苗褐变过程中产生影响的单体酚有绿原酸、芦丁、香豆酸、对香豆酸、表儿茶素、二氢槲皮素;硝酸银处理后的的愈伤组织中,转录因子MYB2、WD40-1、WD40-2与结构基因苯丙氨酸解氨酶(PAL)、黄烷酮醇还原酶(DFR)、查耳酮合酶(CHS)、查尔酮异构酶(CHI)、3-二氢黄酮羟化酶(F3H)、黄酮醇3'-羟化酶(F3'H)的表达量与褐变等级和总酚含量之间存在显著的相关性(P<0.05)。

Tissue culture plantlets of Paeonia ostii ＂Fengdan＂were used as material and inoculated in the basal medium containing 0 - 5.0 mg/L silver nitrate. By measuring the total phenols content, types and content of free phenol and the expression of related genes, the inhibition effects of different concentrations of silver nitrate on callus browning were determined. The results showed that adding silver nitrate in medium inhibited the expressions of related genes, significantly reduced the content of polyphenols in the callus and subsequently reduced browning, of which the comprehensive results by 2.0 mg/L was the best. The main phenols contributing callus browning were chlorogenic acid, rutin, coumaric acid, p-coumaric acid, epicatechin, and dihydro quercetin. In silver nitrate-treated callus, there were significant correlations between the expressions of transcription factors MYB2, WD40-1, and WD40-2, the structural gene phenylalanine ammonia lyase （PAL）, flavanone reductase（ DFR ）, chaleone synthase（ CHS ）, chalcone isomerase（ CHI ）, 3-dihydroflavonol hydroxylase（ F3H ）, flavonol 3＇-hydroxylase （ F3＇H ） and browning grade as well as total phenols content （ P 〈 0.05 ） .