Verhees John, van der Krol Alexander R, Vreugdenhil Dick, van der Plas Linus H W
Wageningen University, The Netherlands.
Plant Mol Biol. 2002 Nov;50(4-5):653-65. doi: 10.1023/a:1019922329081.
Analysis of gene expression and enzyme activity in pooled tuber samples has previously indicated different developmental events occurring in a fixed sequential order during tuber development, starting with the up-regulation of starch synthesis then induction of protein storage followed by cell division and cell enlargement. In this report we analysed in vivo promoter activity of genes related to cell division and storage of reserves during tuber development in individual in vitro tubers, using the non invasive firefly luciferase reporter system. The average activity of the storage related promoters (AGPaseS and lambdaPat21) was up-regulated prior to visible swelling, while the average activity of both cell cycle genes (cycB1;1 and CDC2a) showed an up-regulation after the onset of swelling. However, this novel system allowed expression analysis in individual tubers, which showed a variable up-regulation of both storage genes in relation to the moment of swelling, from 4 days before to 10 days after the onset of swelling. We conclude that during the first stages of tuber development, the moment of storage gene induction is independent from swelling. These results indicate that the developmental program of potato tubers does not consist of a fixed sequential order of events, but consists of independent developmental programs (storage and swelling), together resulting in the formation of a potato tuber. It is concluded that analysis of developmental programs by studying individuals may result in new insights, possibly obscured when using pooled samples.
对汇集的块茎样本中的基因表达和酶活性分析表明，在块茎发育过程中，不同的发育事件按固定的顺序发生，从淀粉合成上调开始，接着是蛋白质储存的诱导，随后是细胞分裂和细胞增大。在本报告中，我们使用非侵入性萤火虫荧光素酶报告系统，分析了单个离体块茎在块茎发育过程中与细胞分裂和储备储存相关基因的体内启动子活性。与储存相关的启动子（AGPaseS和lambdaPat21）的平均活性在可见肿胀之前上调，而两个细胞周期基因（cycB1;1和CDC2a）的平均活性在肿胀开始后上调。然而，这个新系统允许在单个块茎中进行表达分析，结果显示，从肿胀开始前4天到肿胀开始后10天，两个储存基因相对于肿胀时刻的上调情况各不相同。我们得出结论，在块茎发育的最初阶段，储存基因诱导的时刻与肿胀无关。这些结果表明，马铃薯块茎的发育程序不是由固定的顺序事件组成，而是由独立的发育程序（储存和肿胀）组成，共同导致马铃薯块茎的形成。得出的结论是，通过研究个体来分析发育程序可能会带来新的见解，而使用汇集样本时可能会掩盖这些见解。
