低温胁迫对赤霉素代谢的调控研究

Regulation of low temperature stress on gibberellin metabolism

通过4℃处理,对模式植物拟南芥与烟草赤霉素(GA)代谢相关基因的表达进行了分析,结果表明:低温胁迫抑制赤霉素前体GGPP合成通路众多基因的表达,而促进催化GA失活酶编码基因及赤霉素受体基因的表达。通过对超表达Pt GA20ox、Pt GA2ox1及At CBF1的转基因烟草及4℃处理野生型烟草植株GA1含量及代谢相关基因的表达分析表明,低温胁迫下,GGPP合成与GA失活酶编码基因的表达属于主动调控,低温响应通路中关键因子CBF1可能参与了此调控过程,而赤霉素受体基因表达受到了低水平GA的反馈调控。该研究揭示低温胁迫下生长延滞可能是植物主动响应环境变化的过程,通过抑制前体积累及加速失活而降低GA水平可能在植物适应低温胁迫过程中发挥着重要作用。

The expression of genes involved in gibberellin（ GA） metabolism in model plants Arabidopsis thaliana and tobacco（ Nicotiana tabacum） under the 4 ℃ treatment was analyzed. The results indicated that the expressions of many genes in geranylgeranyl diphosphate（ GGPP） synthesis pathway were inhibited,while the expressions of GA deactivation genes and GA receptor genes were promoted. Analysis of GA1 content and the expression metabolism-related genes in over-expressed PtG A20 ox,PtG A2ox1 and AtC BF1 transgenic and 4 ℃-treated wild type tobacco plants showed that the expression of GGPP synthesis genes and GA deactivation genes was active regulation,and the key player,CBF1 in cold response pathway,participated in this regulation process,while the expression of gibberellin receptor genes was feedback regulation by the low levels of GA. This study revealed that growth retardation of plants under cold stress may result from their positive response to the environment. Decreasing GA level by limiting the supply of precursor accumulation and accelerating the deactivation may play a vital role in the process of plants adapting to the cold stress.