外源赤霉素及脱落酸对太子参中乙烯合成关键酶基因表达的影响

摘要

Objective To discuss the influence of exogenous Gibberellin (GA3) and abscisic acid (ABA) on genetic expressions of key enzymes in ethylene synthesis in Taizishen (Pseudostillaria Root, Radix Pseudostellariae) , and provide reference for intelligent use of growth regulators during cultivation of Taizishen.Methods The genes of key enzymes in ethylene synthesis of Taizishen were screened and identified from transcriptome database by using local Blast method.Hai'ershen in full-bloom stage was treated with exogenous GA3 and ABA, and samples were collected at different time points (20 d, 40 d, 50 d and 60 d.The genetic expressions of key enzymes in ethylene synthesis of Taizishen were detected by using real-time fluorescence polymerase chain reaction (RT-PCR).Results There were totally 6 genes of key enzymes in ethylene synthesis in roots of Taizishen obtained, and they were named PhACO1, PhACO2, PhACO3, PhACS1, PhACS2 and PhSAMS.GA3 and ABA could regulated the expressions of above 6 genes, and expressions of PhACO1, PhACO2, PhACS1 and PhSAMS were up-regulated after treated with GA3, and expressions of PhACO3 and PhACS2 were up-regulated after 20 d to 40 d and down-regulated after 50 d to 60 d.The expressions of genes of key enzymes in ethylene synthesis in Taizishen showed down-regulation at first and then up-regulation after treated with ABA, but different genes had different demonstrations.The expression of PhACO1 was up-regulated after 20 d to 60 d, and down-regulated after 40 d to 50 d.The expressions of PhACO2 and PhACO3 were down-regulated after 20 d to 50 d, and up-regulated after 60 d.The expression of PhACS1 was down-regulated after 20, up-regulated after 40 d to 60 d.The expressions of PhACS2 and PhSAMS were down-regulated.Conclusion GA3 and ABA may control the ethylene signaling pathway to regulate plant growth through affecting the ethylene biosynthesis of Taizishen.It is speculated that Taizishen is treated with suitable concentration of GA3 in adventitious root growth period and treated with ABA treatment in root thickening period, the yield of Taizishen will be increased.%目的 探讨外源赤霉素 (GA3) 和脱落酸 (ABA) 对乙烯合成关键酶基因表达的影响, 为孩儿参栽培过程中生长调节剂的合理使用提供参考.方法 构建本地Blast, 从转录组数据库中筛选鉴定孩儿参乙烯合成关键酶基因, 以外源赤霉素和脱落酸处理盛花期孩儿参, 分别于20、40、50、60 d时采集块根, 实时荧光PCR法检测乙烯合成关键酶基因的表达.结果 筛选得到乙烯合成关键酶基因共6个, 命名为PhACO1、PhACO2、PhACO3、PhACS1、PhACS2、PhSAMS.赤霉素和脱落酸均可调节6个基因的表达, 其中赤霉素处理后PhACO1、PhACO2、PhACS1、PhSAMS基因表达在各时期均上调, 而PhACO3和PhACS2在处理20～40 d时表达上调、50～60 d时下调.脱落酸处理后各基因表达量虽然总体呈现先下调后上调趋势, 但具体表现有差别, PhACO1基因在20、60 d表现为上调作用, 40～50 d表现为下调作用;PhACO2、PhACO3基因则在20～50 d表现为下调作用, 60 d时则表现为上调作用;PhACS1基因20 d表现为下调作用, 40～60 d表现为上调作用;PhACS2和PhSAMS基因则均表现为下调作用.结论 赤霉素和脱落酸可能通过影响乙烯的生物合成实现对乙烯信号通路的调控, 进而调节植物生长, 推测在孩儿参不定根生长期用适宜浓度的赤霉素处理, 块根膨大期用脱落酸处理可以获得较大的块根, 增加太子参产量.