植物生长素合成酶iaaM基因在烟草韧皮部

为探讨生长素过度合成对植物韧皮部发育的影响,利用韧皮部特异表达的拟南芥蔗糖合成酶基因启动子与色氨酸单加氧酶基因(iaaM)重组,构建载体,通过根癌农杆菌介导的叶盘转化法将其转入烟草,获得了转化的烟草植株。大多转基因烟草都表现出叶片卷曲、植株生长异常的生长素过度表型。转基因烟草植株生长较野生型烟草(对照)植株明显迟缓,但其茎横切面韧皮部细胞显著增多,排列更加紧密整齐,木质部也较早开始分化。转基因烟草茎段有大量不定根分化,其根部则在韧皮部薄壁细胞处诱生大量根原基,在不定根上有大量侧根和根毛的分化。

The effects of over expression of auxin synthesis gene iaaM in Nicotiana tabacum's Phloem

We constructed a plant phloem-specific expression iaaM vector to study the effect of IAA over-expression on phloem development.The vector was constructed by recombining the tryptophan monooxygenase gene(iaaM) with the phloem-specific promoter and the sucrose synthesis gene promoter of Arabidopsis thaliana.The recombinant was transformed into Nicotiana tabacum and several transgenic plants were screened out.Most of the transgenic plants showed abnormal morphologies as leave curling and delayed development and the seedlings grew slower compared to the wild control.The section observation of the stem showed that more secondary xylem and phloem cells were produced in transgenic plants compared to the wild-type.In addition,there were many adventitious roots abnormally grown out in the transgenic stems and numerous root hairs and lateral roots occurred in transgenic root.