Studies on bulb formation and dormancy in bulbous plants by molecular biological approach

利用分子生物学研究探讨了鳞茎形成诱导和鳞茎休眠诱导是同一现象的假说。以风信子未成熟叶片为外植体，研究了风信子幼叶外植体的组织培养。代尔夫特蓝)，在含有NAA和BA的MS培养基上25℃培养。外植体在5℃冷处理后形成4个鳞茎，而未经冷处理的外植体鳞茎形成受到抑制。ABA不经冷处理可促进鳞茎的形成。冷处理外植体的鳞茎形成受到抑制。在鳞茎形成条件下，内源ABA含量增加。这些结果表明，鳞茎的形成受低温诱导，并受ABA的调节。因此，控制方法是通过冷处理或BAB获得不经冷处理的鳞茎形成条件，而非鳞茎形成条件是通过非冷处理或氟里酮加冷处理。…诱导的基因差异显示分析在风信子鳞茎形成过程中进行了较多的低温处理和ABA处理。观察到冷处理和未冷处理的枝条样品之间的差异片段。6个差异扩增片段在冷处理和ABA处理中普遍表达，2个在两个处理中均被抑制。通过对18个特异基因片段进行部分序列测定，发现两种处理均可扩增出与风信子鳞茎形成有关的片段。有8个克隆与FASTA程序鉴定的序列同源性在80%以上。经低温诱导和ABA诱导后的HL克隆与拟南芥或栽培稻的基因组DNA同源。3个HL克隆与甘薯淀粉磷酸化酶基因部分同源。一些HL克隆与功能已知的基因或mRNAs同源。功能未知的HL克隆有可能是与鳞茎形成相关的新基因。较少

Molecular biological studies were used to investigate the hypothesis that the induction of bulb formation and the induction of bulb dormancy are the same phenomenon. Shoot explants were taken from in vitro immature leaves of hyacinth (Hyacinthus orientalis L. cv. Delft Blue) and cultured at 25℃ on MS medium containing NAA and BA. The explants formed bulbs four after the cold treatment at 5℃, whereas bulb formation was supressed without cold treatment. ABA promoted bulb formation without cold treatment. By flundone, bulb formation of the cold treated explants was inhibited. Under bulb-forming conditions, endogenous ABA content increased. These results suggest that bulb formation is induced by low temperature and regulated by ABA. Thus, the controlling methods are bulb forming conditions are obtainable by cold treatment or BAB without cold treatment and non-bulb forming conditions are by non-cold treatment or fluridone with cold treatment.Differential display analysis of genes induced by … More low temperature and ABA in bulb formation of hyacinth was conducted. Differential PCR amplified fragments between cold-treated and non-cold-treated shoot samples were observed. Six differential PCR amplified fragments were commonly expressed both in the cold and ABA treatments, and two were suppressed in both treatments. The cDNA amplified fragments observed in both treatments might be related to bulb formation in hyacinth.The partial sequences of the cDNA clones obtained from 18 specific gene fragments by low temperature (designated as HL clones) were carried out. Eight HL clones had over 80% identity with identified sequences with FASTA program. The HL clones of cDNA induced by low temperature and ABA were homologous to genome DNA of A. thaliana or O. sativa. Three HL clones showed partial identity with starch phosphorylase gene of I. batatas. Some HL clones were homologous to genes or mRNAs of which the function had been suggested. It is possible that HL clones of which the functions were not clarified are novel genes related to bulb formation. Less