重组马铃薯X病毒载体介导的烟草γ-微管蛋白基因沉默

用重组马铃薯X病毒(potato virus X,PVX)载体将γ-微管蛋白反义基因导入烟草(Nicotiana tabacum var.Samsun NN),得到了γ-微管蛋白基因沉默的烟草植株。它与侵染PVX空载体的正对照相比有明显的差异:不同形态的叶片分层交替生长;到生殖期所有的花苞都提前脱落;小孢子不能发育到四分体阶段。沉默的形态反应主要起始于顶端幼嫩组织。在沉默过程中除存在基因沉默及恢复现象外还出现靶基因水平的陡然升高,甚至有时会明显反超过正常对照水平。

Tobacco gamma-tubulin gene silencing mediated by recombinant potato virus X vector]

Gamma-tubulin gene is a very important house-keeping gene and plays key roles in cell division, microtubule nucleation and cell cycle regulation in both plants and animals. In this paper, we studied the gamma-tubulin gene silencing in Nicotiana tabacum var. Samsun NN using the recombinant PVX vector with D fragment of gamma-tubulin cDNA. Special phenotype appeared from recombinant PVX-vector-infected plants, the different morphological leaves grew alternatively in leaf layers (Figs.3-5), and all the buds fell off gradually (Fig.4), resulting in failure of all the microspores to develop to the tetrad stage (Fig.8). The silencing initiated from the apical tissue and kept on until it was mature (Figs.3, 4). There was the increasing of target gene mRNA obviously during gene silencing, even to exceed the positive control (Fig.6). The PVX vector was also suppressed strongly and could fluctuate to some degree (Fig.9), which was probably correlated with target gene mRNA expression.