Department of Molecular Genetics, Center for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Campus Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain.
J Plant Physiol. 2013 Jun 15;170(9):864-73. doi: 10.1016/j.jplph.2013.01.004. Epub 2013 Feb 4.
Late Embryogenesis Abundant (LEA) proteins participate in plant stress responses and contribute to the acquisition of desiccation tolerance. In this report Rab28 LEA gene has been over-expressed in maize plants under a constitutive maize promoter. The expression of Rab28 transcripts led to the accumulation and stability of Rab28 protein in the transgenic plants. Native Rab28 protein is localized to nucleoli in wild type maize embryo cells; here we find by whole-mount immunocytochemistry that in root cells of Rab28 transgenic and wild-type plants the protein is also associated to nucleolar structures. Transgenic plants were tested for stress tolerance and resulted in sustained growth under polyethyleneglycol (PEG)-mediated dehydration compared to wild-type controls. Under osmotic stress transgenic seedlings showed increased leaf and root areas, higher relative water content (RWC), reduced chlorophyll loss and lower Malondialdehyde (MDA) production in relation to wild-type plants. Moreover, transgenic seeds exhibited higher germination rates than wild-type seeds under water deficit. Overall, our results highlight the presence of transgenic Rab28 protein in nucleolar structures and point to the potential of group 5 LEA Rab28 gene as candidate to enhance stress tolerance in maize plants.
晚期胚胎丰富蛋白（LEA）参与植物应激反应，并有助于获得干燥耐受性。在本报告中，Rab28 LEA 基因在组成型玉米启动子的控制下在玉米植物中过表达。Rab28 转录本的表达导致 Rab28 蛋白在转基因植物中的积累和稳定。天然 Rab28 蛋白在野生型玉米胚胎细胞的核仁中定位；在这里，我们通过全胚免疫细胞化学发现，在 Rab28 转基因和野生型植物的根细胞中，该蛋白也与核仁结构相关。对转基因植物进行了应激耐受性测试，结果表明与野生型对照相比，在聚乙二醇（PEG）介导的脱水条件下，转基因植物能够持续生长。在渗透胁迫下，与野生型植物相比，转基因幼苗的叶片和根面积增加，相对含水量（RWC）更高，叶绿素损失减少，丙二醛（MDA）生成减少。此外，在水分亏缺下，转基因种子的萌发率高于野生型种子。总的来说，我们的研究结果突出了转基因 Rab28 蛋白在核仁结构中的存在，并表明组 5 LEA Rab28 基因作为增强玉米植物应激耐受性的候选基因具有潜力。
