Plomion C, Pionneau C, Brach J, Costa P, Baillères H
Institut National de la Recherche Agronomique, Equipe de Génétique et Amélioration des Arbres Forestiers, BP45, 33610 Pierroton, France.
Plant Physiol. 2000 Jul;123(3):959-69. doi: 10.1104/pp.123.3.959.
When a conifer shoot is displaced from its vertical position, compression wood (CW) is formed on the under side and can eventually return the shoot to its original position. Changes in cell wall structure and chemistry associated with CW are likely to result from differential gene/protein expression. Two-dimensional polyacrylamide gel electrophoresis of differentiating xylem proteins was combined with the physical characterization of wooden samples to identify and characterize CW-responsive proteins. Differentiating xylem was harvested from a 22-year-old crooked maritime pine (Pinus pinaster Ait.) tree. Protein extracted from different samples were revealed by high-resolution silver stained two-dimensional polyacrylamide gel electrophoresis and analyzed with a computer-assisted system for single spot quantification. Growth strain (GS) measurements allowed xylem samples to be classified quantitatively from normal wood to CW. Regression of lignin and cellulose content on GS showed that an increase in the percentage of lignin and a decrease of the percentage of cellulose corresponded to increasing GS values, i.e. CW. Of the 137 studied spots, 19% were significantly associated with GS effect. Up-regulated proteins included 1-aminocyclopropane-1-carboxylate oxidase (an ethylene forming enzyme), a putative transcription factor, two lignification genes (caffeic O-methyltransferase and caffeoyl CoA-O-methyltransferase), members of the S-adenosyl-L-methionine-synthase gene family, and enzymes involved in nitrogen and carbon assimilation (glutamine synthetase and fructokinase). A clustered correlation analysis was performed to study simultaneously protein expression along a gradient of gravistimulated stressed xylem tissue. Proteins were found to form "expression clusters" that could identify: (a) Gene product under similar control mechanisms, (b) partner proteins, or (c) functional groups corresponding to specialized pathways. The possibility of obtaining regulatory correlations and anticorrelations between proteins provide us with a new category of homology (regulatory homology) in tracing functional relationships.
当针叶树的嫩枝从垂直位置被移位时，其下侧会形成压缩木（CW），最终可使嫩枝恢复到原来的位置。与压缩木相关的细胞壁结构和化学变化可能是由基因/蛋白质表达差异所致。将分化木质部蛋白质的二维聚丙烯酰胺凝胶电泳与木质样品的物理特性相结合，以鉴定和表征对压缩木产生响应的蛋白质。从一棵22年树龄的弯曲海岸松（Pinus pinaster Ait.）树上采集分化木质部。通过高分辨率银染二维聚丙烯酰胺凝胶电泳显示从不同样品中提取的蛋白质，并用计算机辅助系统进行单点定量分析。生长应变（GS）测量使木质部样品能够从正常木材到压缩木进行定量分类。木质素和纤维素含量与生长应变的回归分析表明，木质素百分比增加而纤维素百分比降低与生长应变值增加相对应，即与压缩木相对应。在所研究的137个斑点中，19%与生长应变效应显著相关。上调的蛋白质包括1-氨基环丙烷-1-羧酸氧化酶（一种乙烯形成酶）、一种假定的转录因子、两个木质化基因（咖啡酸O-甲基转移酶和咖啡酰辅酶A-O-甲基转移酶）、S-腺苷-L-甲硫氨酸合成酶基因家族成员以及参与氮和碳同化的酶（谷氨酰胺合成酶和果糖激酶）。进行了聚类相关性分析，以同时研究沿重力刺激应激木质部组织梯度的蛋白质表达。发现蛋白质形成了“表达簇”，这些簇可以识别：（a）受相似控制机制调控的基因产物，（b）伴侣蛋白，或（c）对应于特定途径的功能组。获得蛋白质之间调控相关性和反相关性的可能性为我们在追踪功能关系时提供了一种新的同源性类别（调控同源性）。
