Xyloglucan endotransglucosylase and cell wall extensibility
Xyloglucan endotransglucosylase and cell wall extensibility
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DOI：
10.1016/j.jplph.2010.06.029
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发表时间：
2011-02-15
影响因子：
4.3
通讯作者：
Lorences, E. P.
中科院分区：
文献类型：
--
作者：
Miedes, E.;Zarra, I.;Lorences, E. P.
以转XTH基因的番茄下胚轴为材料，研究了XET活性对下胚轴生长和细胞壁伸长性的影响。与野生型相比，转基因下胚轴中SIXTH1的表达显著增强(品系13)或共抑制(品系33)，这些结果与特定可溶性XET活性的结果相关，表明SIXTH1主要翻译为可溶性XET同工酶。XET活性与细胞壁延伸性之间存在一定的关系，总延伸率最高的是高表达SIXTH1系的顶端下胚轴节段，XET比活性和下胚轴生长量也高于野生系。在共抑制SIXTH1品系中，总延伸值低于野生型品系。FTIR对细胞壁多糖之间联系的研究表明，高表达SIXTH1并具有较高XET特异性活性的下胚轴远离野生系，这表明果胶之间以及纤维素和木聚糖之间的联系可能不同。这些结果表明，转基因株系中XET活性增加的作用可能与细胞壁结构的变化有关，从而改变了细胞壁的延伸性。另一方面，MALDI-TOF-MS对木葡聚糖低聚糖组成的分析结果没有品系间的差异，说明木聚糖的结构不受XET作用的影响。这些结果表明，第I组的XTHs主要参与生长发育过程中细胞壁的重组，但不是植物生长的限制因子。(C)2010年爱思唯尔股份有限公司。版权所有。
Transgenic tomato hypocotyls with altered levels of an XTH gene were used to study how XET activity could affect the hypocotyl growth and cell wall extensibility. Transgenic hypocotyls showed significant over-expression (line 13) or co-suppression (line 33) of the SIXTH1 in comparison with the wild type, with these results being correlated with the results on specific soluble XET activity, suggesting that SIXTH1 translates mainly for a soluble XET isoenzyme. A relationship between XET activity and cell wall extensibility was found, and the highest total extensibility was located in the apical hypocotyl segment of the over-expressing SIXTH1 line, where the XET-specific activity and hypocotyl growth were also highest compared with the wild line. Also, in the co-suppression SIXTH1 line, total extensibility values were lower than in the wild type line. The study of linkages between cell wall polysaccharides by FTIR showed that hypocotyls over-expressing SIXTH1 and having a higher XET-specific activity, were grouped away from the wild line, indicating that the linkages between pectins and between cellulose and xyloglucans might differ. These results suggested that the action of the increased XET activity in the transgenic line could be responsible for the cell wall structural changes, and therefore, alter the cell wall extensibility. On the other hand, results on xyloglucan oligosaccharides composition of the xyloglucan by MALDI TOF-MS showed no differences between lines, indicating that the xyloglucan structure was not affected by the XET action. These results provide evidences that XTHs from group I are involved mainly in the restructuring of the cell wall during growth and development, but they are not the limiting factor for plant growth. (C) 2010 Elsevier GmbH. All rights reserved.