脯氨酸参与植物开花信号转导途径

作为一种渗透调节物质,人们对脯氨酸已经有了很多的研究,然而脯氨酸在生命体生长发育中的作用还知之甚少。为了研究脯氨酸在生长发育中的作用,筛选得到了拟南芥的脯氨酸抗性突变体kao2。突变体在不同浓度脯氨酸培养基上均表现出抗性,但是突变体中脯氨酸的吸收没有显著变化,降解关键基因表达也没有增多。Tail-PCR进行突变基因克隆的结果表明,T-DNA插入位点位于AtKAO2(At2g32440)的第一个外显子,且插入导致AtKAO2基因不再表达。拟南芥突变体库中订购的kao2-2同样表现出脯氨酸抗性表型。此外,kao2表现出胁迫敏感表型。kao2表现出明显的晚花表型,并且赤霉素的添加能够部分挽救晚花表型。而kao2突变体中开花抑制因子FLC表达升高,而开花促进基因FT的表达降低。研究在脯氨酸与开花信号转导途径之间建立了联系,为脯氨酸对开花途径的信号作用提供了新的证据,为以后的研究提供了新的材料。

Proline is involved in flowering signal transduction pathway in Arabidopsis

Although proline has been studied as an osmotic adjustment substance, its function in the plant growth and development, particularly in flowering, is less known. In order to discuss the function of proline in plant growth and development, we screened the proline resistant mutants named kao2 in Arabidopsis. The kao2 performed proline resistant in medium containing different content proline, but there are no difference between wild type and kao2 in the proline absorption. The expression of PDH, key enzyme for proline degradation, was lower in kao2 but not higher. The t-DNA inserted to the first exon of AtKAO2 (At2g32440) gene, caused AtKAO2 no longer express. Another mutant kao2-2 bought in the ABRC showed proline resistant, too. kao2 was super-sensitivity to other stress including NaCl, mannitol, and ABA. kao2 showed late flowering phenotype, and the spraying of gibberellin can partly rescue the late flowering phenotype. The expression of FLC, a flowering inhibitor, was higher in kao2 than wild type, and FT, a flowering promoting factor, lower in kao2 than wild type. Our study established the contact between proline and flowering signaling pathway, afforded new proof for proline promoting flowering, and produced new material for future study.