A germination-related gene encoding a serine carboxypeptidase is expressed during the differentiation of the vascular tissue in wheat grains and seedlings
A germination-related gene encoding a serine carboxypeptidase is expressed during the differentiation of the vascular tissue in wheat grains and seedlings
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DOI：
10.1007/s00425-002-0809-2
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发表时间：
2002-09-01
期刊：
影响因子：
4.3
通讯作者：
Cejudo, FJ
中科院分区：
文献类型：
--
作者：
Domínguez, F;González, MC;Cejudo, FJ
糊粉层中表达的羧肽酶参与谷物发芽过程中胚乳储存蛋白的动员。编码这些蛋白质的基因也在发芽谷物的盾片中表达，但它们在该器官中的功能尚不清楚。我们分析了发芽小麦 (Triticum aestivum L.) 籽粒中羧肽酶 III (CPIII) 基因的表达。 CPIII 转录物在盾片中短暂积累，在吸入后 2-3 天达到最大值，并且仅定位于盾片维管组织。对生长中的幼苗发育中的芽和根中 CPIII 表达的分析证实了 CPIII 转录本定位于分化的维管组织。 TUNEL 检测在显示 CPIII 表达的细胞中检测到原位核 DNA 片段，表明它们经历了程序性细胞死亡。相对RT-PCR分析表明，在糊粉细胞中高水平表达的CPIII基因是在营养组织中表达的基因，并允许将该基因用作小麦幼苗气管元件分化的分子标记。这些结果表明，丝氨酸羧肽酶参与了小麦维管组织发育过程中的程序性细胞死亡，这是这些酶除了在发芽过程中动员淀粉胚乳蛋白之外的新作用。
Carboxypeptidases expressed in the aleurone layer participate in the mobilization of endosperm storage proteins during cereal grain germination. The genes encoding these proteins are also expressed in the scutellum of germinating grains, but their function in this organ is not yet clear. We have analyzed the expression of a carboxypeptidase III (CPIII) gene in germinating wheat (Triticum aestivum L.) grains. CPIII transcripts accumulated transiently in the scutellum showing a maximum at 2-3 days after imbibition and were exclusively localized to the scutellar vascular tissue. The analysis of CPIII expression in developing shoots and roots from growing seedlings confirmed the localization of CPIII transcripts to differentiating vascular tissue. The TUNEL assay detected in situ nuclear DNA fragmentation in cells showing CPIII expression, indicating that they undergo programmed cell death. Relative RT-PCR analysis showed that the CPIII gene expressed at high level in aleurone cells is the one expressed in vegetative tissues, and allowed the use of this gene as a molecular marker of tracheary element differentiation in wheat seedlings. These results are indicative of the involvement of serine carboxypeptidases in programmed cell death during the development of the vascular tissue in wheat, a new role for these enzymes, besides the mobilization of starchy-endosperm proteins during germination.