毛白杨PtAUX1超表达诱导体状胚发生

体状胚的发生由一个生长素信号级联系统控制,其发生过程需要大量的生长素,随后在去除生长素或降低生长素浓度的条件下,体状胚趋于成熟。除植物激素外,环境胁迫也是体状胚发生所必须的,激素和环境胁迫协同诱导细胞的脱分化、再分化和体状胚的发生。目前发现的参与体状胚发生的主要基因有SERK、PKL和BBM等,它们作用于体状胚的不同发育阶段。本研究中,在毛白杨35S::PtAUX1超表达植株中发现叶片表面产生大量体状胚,体状胚分散在叶片主脉及侧脉两侧或聚集在叶片边缘,其中部分体状胚可发育成成熟体状胚。将成熟体状胚取下,置于MS0培养基上进行培养,体状胚发芽并缓慢产生根。研究结果表明,PtAUX1通过建立新的生长素浓度梯度,诱导体细胞转化成胚性细胞,从而使叶片产生出体状胚。除上述基因外,PtAUX1也参与体状胚的发生,这一研究发现现尚未见报道。

Over-expression of PtAUX1 Triggers Somatic Embryo Initiation of Populus tomentosa Carr.

Somatic embryogenesis is controlled by an auxin signaling cascade system.Somatic embryo induction process requires a large number of auxin,then somatic embryos mature after removing or reducing auxin concentration.In addition to the plant hormone,environmental stress is necessary for somatic embryogenesis,hormones and environmental stress synergistically induce cell dedifferentiation,differentiation and somatic embryogenesis.At present,there are primary genes participating in the somatic embryogenesis like SERK,PKL,BBM,etc.,they contribute to the different stages of somatic embryogenesis.In this paper,the over-expression of 35S::PtAUX1 plants of Populus tomentosa produce a large amount of somatic embryos,they scattered in the main vein and lateral veins on both sides of blade or gathered in leaf margins,and some of them can develop into mature embryos.The mature somatic embryos can germinate and produce roots slowly after being removed and cultured in MS0 medium.The result shows that,PtAUX1 can induce somatic embryos in leaf.In addition to the above genes,PtAUX1 is also involved in the somatic embryogenesis,this finding is yet to be reported.