Spatial specificity of H2O2-generating oxalate oxidase gene expression during wheat embryo germination
Spatial specificity of H2O2-generating oxalate oxidase gene expression during wheat embryo germination
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DOI：
10.1046/j.1365-313x.1998.00191.x
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发表时间：
1998-07-01
期刊：
影响因子：
7.2
通讯作者：
Cuming, AC
中科院分区：
文献类型：
--
作者：
Caliskan, M;Cuming, AC
Germin是小麦胚萌发的分子标记，是一种抗蛋白酶的、质外体的、具有过氧化物生成草酸氧化酶活性的五聚体糖蛋白。用组织化学、免疫细胞化学和原位杂交相结合的方法，研究了萌发小麦胚组织中类萌发草酸氧化酶（gl-OXO）基因表达的空间特异性。gl-OXO mRNA和蛋白质的合成和积累在吸胀的第一个24小时期间定位于胚轴（特别是胚芽鞘）的包膜组织内。通过48小时发芽，gl-OXO积累检测整个根，除了细胞伸长的有丝分裂后区，其转录物的积累仅限于外细胞层。此时，在伸长的芽中，gl-OXO仅限于胚芽鞘，在胚芽鞘中仅在表皮细胞层、维管束和束鞘细胞中检测到。在较老的幼苗中（吸胀后约9天），在叶中检测到gl-OXO活性，但仅在维管束内。这些表达模式与以下假设一致：gl-OXO的生物学功能是通过局部提供过氧化氢以交联细胞壁成分来参与细胞壁重组，从而限制细胞生长。
Germin, a molecular marker of wheat embryo germination, is a protease-resistant, apoplastic, homopentameric glycoprotein with peroxide-generating oxalate oxidase activity. The spatial specificity of germin-like oxalate oxidase (gl-OXO) gene expression has been determined in tissues of germinating wheat embryos by a combination of histochemical, immunocytochemical and in situ hybridization techniques. The synthesis and accumulation of gl-OXO mRNA and protein is localised within the enveloping tissues of the embryonic axis (particularly the coleorhiza) during the first 24 h of imbibition. By 48 h germination, gl-OXO accumulation is detected throughout the root, with the exception of the postmitotic zone of cell elongation, where accumulation of its transcript is restricted to outer cell layers. At this time in the elongating shoot, gl-OXO is restricted to the coleoptile where it is detected only in the epidermal cell layer, the vascular bundles and bundle sheath cells. In older seedlings (approximately 9 days post-imbibition) gl-OXO activity is detected in leaves, but only within the vascular bundles. These patterns of expression are consistent with the hypothesis that the biological function of gl-OXO is to restrict cell growth by participating in cell-wall restructuring through the local provision of hydrogen peroxide for cross-linking of wall components.