油菜素内酯对烟草幼苗根系构型的影响及调控机制  

Effect of Brassinolide on Root Architecture of Tobacco Seedlings and Regulation Mechanism

作　　者：梁栋 刘光亮[2] 石屹[2] 王树声[2] 王程栋[2] 王晓琳 LIANG Dong;LIU Guangliang;SHI Yi;WANG Shusheng;WANG Chengdong;WANG Xiaolin(Lushi County Branch of Sanmenxia Tobacco Company,Lushi 472200,China;Tobacco Research Institute,Chinese Academy of Agricultural Sciences/Key Laboratory of Tobacco Biology and Processing,Ministry of Agriculture and Rural Affairs,Qingdao 266101,China)

机构地区：[1]三门峡市烟草公司卢氏县分公司,河南卢氏472200 [2]中国农业科学院烟草研究所/农业农村部烟草生物学与加工重点实验室,山东青岛266101

出　　处：《河南农业科学》2022年第8期37-44,共8页Journal of Henan Agricultural Sciences

基　　金：中国农业科学院科技创新工程项目(ASTIP-TRIC03)。

摘　　要：为探究油菜素内酯(BRs)对烟草幼苗根系构型的调控机制,选取烤烟品种农大202为试验材料,分析不同浓度外源EBR(2,4-表油菜素内酯)和BRZ(BRs合成抑制剂)处理下烟草幼苗根系构型的差异,通过电镜观察二级侧根根尖横截面变化,并观察烟草转基因DR5::GUS材料根系GUS(β-葡萄糖苷酸酶)染色情况,测定侧根中生长素含量和相关基因表达量,分析根系构型变化与生长素之间的关系。结果表明,EBR可以调节烟草幼苗根长、根系直径与二级侧根密度变化,较低浓度的EBR(0.1 nmol/L)使总根长增加,增幅达到29.0%,但在0.5、1、5、10、100 nmol/L EBR处理下,一级侧根长度与对照(不添加EBR和BRZ)相比分别降低4.6%、9.6%、18.5%、29.6%、36.9%;随着EBR浓度的增大(0.1~10 nmol/L),二级侧根密度不断增大,但根系平均直径逐渐减小,BRZ(100~500 nmol/L)处理后烟草根系平均直径显著增大;EBR主要通过调控烟草侧根细胞数目和中柱直径影响烟草幼苗根系直径大小,10 nmol/L EBR处理下烟草二级侧根横切直径较CK显著减少32.5%,中柱直径较CK显著减小25.0%;10 nmol/L EBR处理下,烟草侧根生长素含量较CK显著降低7.1%,500 nmol/L BRZ处理下,侧根生长素含量与CK相比无变化;EBR处理使烟草生长素运输基因家族中PIN3a T、PIN3b S、PIN3b T和PIN11T等基因上调,从而调控根中生长素的分布。可见,油菜素内酯可以调控根中不同部位生长素的水平进而影响烟草根系构型的变化。In order to explore the regulation mechanism of brassinolide(BRs)on root architecture of tobacco seedlings,the differences of root architecture under different concentrations of exogenous EBR(2,4-epibrassinolide)and BRZ(brassinolide synthesis inhibitor)were investigated using the flue-cured tobacco Nongda 202.The changes of root tip cross-section of secondary lateral roots were observed by electron microscope,and the auxin content,GUS(β-glucosidase)staining and relative gene expression in lateral roots were determined to analyze the relationship between root architecture and auxin.The results showed that EBR could affected root length,root diameter and secondary lateral root density of tobacco seedlings.Lower concentration of EBR(0.1 nmol/L)increased the total root length by 29.0%,but higher EBR,such as 0.5,1,5,10 and 100 nmol/L declined the primary lateral root length by 4.6%,9.6%,18.5%,29.6%and 36.9%respectively.As the EBR concentration(0.1—10 nmol/L)increased,the density of secondary lateral roots increased,but the average root diameter gradually decreased.The average root diameter of tobacco increased significantly in BRZ treatment(100—500 nmol/L).EBR affected the root diameter of tobacco seedlings mainly by regulating the number of tobacco lateral root cells and the diameter of column,the cross cutting diameters of secondary lateral root and column under10 nmol/L EBR treatment were significantly reduced by 32.5%and 25.0%compared with CK(No EBR and BRZ).The auxin content of lateral root decreased by 7.1%significantly under 10 nmol/L EBR treatment,but there was no change of lateral root auxin under 500 nmol/L BRZ treatment.EBR treatment increased the expression of PIN3aT,PIN3bS,PIN3bT and PIN11T in tobacco,which was considered to change the distribution of auxin in roots.Therefore,brassinolide can regulate the level of auxin in different parts of roots,and then affect the changes of tobacco root architecture.

关 键 词：烟草 油菜素内酯 根系构型 侧根密度 侧根直径 生长素 

分 类 号：S572[农业科学—烟草工业]