大白菜 LBD 基因参与愈伤组织发生及植株再生初探

摘要

植物离体再生主要经历愈伤组织形成、胚状体或器官发生和不定芽产生等过程，其中愈伤组织形成是在外源生长素和相关蛋白因子的共同作用下完成的，是植物离体再生的关键环节。拟南芥 LBD16、LBD17、LBD18和LBD29是促进胚性愈伤组织发生的关键转录因子。通过对37种白菜高代自交系外植体芽再生频率的统计分析，选出具有显著差异的材料，研究了大白菜愈伤组织发生过程中上述同源LBD基因的表达变化模式，初步分析了LBD基因表达对大白菜愈伤组织产生和再生频率的影响。结果显示：白菜LBD基因与拟南芥LBD基因有很高的序列同源性，共有8个上述基因的同源基因；离体培养的白菜外植体在诱导7 d时产生愈伤组织，而LBD基因在此时表达量达到最高，然后开始降低，在整个愈伤诱导过程中呈现先上升后下降的趋势；在愈伤诱导各时期中，LBD基因在高再生频率材料中的表达一般都要高于低再生材料。这些结果表明，LBD基因参与大白菜愈伤组织产生并促进离体组织植株再生的关键基因，这为从分子水平上筛选高效再生材料，建立高效遗传转化体系奠定了基础。%Callus formation ,embryogenesis and adventitious bud development are major steps of plant regenera-tion,in which callus formation is a key step .Previous reports demonstrated that exogenous auxin and LBD ( Lateral organ boundaries domain ) genes,LBD16,LBD17,LBD18 and LBD29,were involved in callus formation in Arabi-dopsis.Shoot regeneration frequency of 37 high inbred line of Chinese cabbage were analyzed and 2 of them,with significant different regeneration frequency ,were selected for further study .Here ,we focused on the function of Bras-sica LBD genes in callus formation and plant regeneration by analyzing LBD expression level during callus induction of Chinese cabbage with different regeneration capacity .The main results are as follows:BrLBD genes are highly ho-mologous to Arabidopsis LBD genes,and a total of 8 relevant LBD homologous are found in Brassica genome .Visible callus tissue began to appear within 7 days after explant inoculation ,and interestingly ,Brassica LBD genes were de-tected to reach its highest expression level at the time point and the levels first increased and then decrease in the process of regeneration;At every time point during callus induction ,LBD genes expressed a higher level in materials with high regeneration frequency than that with low regeneration frequency .All these results revealed that LBD genes were involved in callus formation and promoted plant regeneration in vitro.This may provide us a new per-spective for large-scale screening of high-frequency regeneration materials to establish efficient genetic transforma-tion system at the molecular level .