Interdepartmental Genetics Graduate Program, Iowa State University, USA.
J Plant Physiol. 2011 May 1;168(7):734-8. doi: 10.1016/j.jplph.2010.10.002. Epub 2010 Nov 18.
Previous SDS PAGE gel analysis of the floral nectars from petunia and tobacco plants revealed significant differences in the protein patterns. Petunia floral nectar was shown to contain a number of RNase activities by in gel RNase activity assay. To identify these proteins in more detail, the bands with RNase activity were excised from gel and subjected to trypsin digestion followed by LC-MS/MS analysis. This analysis revealed that S-RNases accumulate in nectar from Petunia hybrida, where they should carry out a biological function different from self-pollen rejection. In addition, other proteins were identified by the LC-MS/MS analysis. These proteins include a peroxidase, an endochitinase, and a putative fructokinase. Each of these proteins contained a secretory signal sequence that marked them as potential nectar proteins. We developed RT-PCR assays for each of these five proteins and demonstrated that each of these proteins was expressed in the petunia floral nectary. A discussion of the role of these proteins in antimicrobial activity in nectar is presented.
先前对矮牵牛和烟草植物花蜜的 SDS-PAGE 凝胶分析显示，蛋白质图谱存在显著差异。凝胶内 RNase 活性测定表明，矮牵牛花蜜含有多种 RNase 活性。为了更详细地鉴定这些蛋白质，从凝胶中切下具有 RNase 活性的条带，进行胰蛋白酶消化，然后进行 LC-MS/MS 分析。该分析表明，S-RNases 在杂种矮牵牛的花蜜中积累，在那里它们应该执行不同于自身花粉排斥的生物学功能。此外，通过 LC-MS/MS 分析还鉴定了其他蛋白质。这些蛋白质包括过氧化物酶、内几丁质酶和一种假定的果糖激酶。这些蛋白质都含有一个分泌信号序列，将它们标记为潜在的花蜜蛋白。我们为这五种蛋白质中的每一种都开发了 RT-PCR 检测方法，并证明这些蛋白质中的每一种都在矮牵牛花蜜腺中表达。本文还讨论了这些蛋白质在花蜜中的抗菌活性中的作用。
