Expression of arginine decarboxylase and ornithine decarboxylase genes in apple cells and stressed shoots
Expression of arginine decarboxylase and ornithine decarboxylase genes in apple cells and stressed shoots
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DOI：
10.1093/jxb/eri102
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发表时间：
2005-04-01
影响因子：
6.9
通讯作者：
Moriguchi, T
中科院分区：
文献类型：
--
作者：
Hao, YJ;Kitashiba, H;Moriguchi, T
精氨酸脱羧酶（ADC）和鸟氨酸脱羧酶（ODC）是腐胺生物合成的两个重要酶。本研究从苹果[Malus sylvestris（L.）Mill.变种Artistica（Borkh.）Mansf.]。同时，部分ODC（pMdODC）只能通过第二RCR从RT-PCR产物中扩增，而全长ODC不能通过cDNA文库筛选或5 '-和3'-RACE获得，表明表达量很低。此外，D-精氨酸，ADC抑制剂，导致ADC活性下降，严重抑制苹果愈伤组织的生长，这可以部分恢复外源添加腐胺，而α-二氟甲基鸟氨酸（DFMO），ODC抑制剂，导致愈伤组织生长的不完全抑制，而不改变ODC活性。RNA凝胶印迹分析表明，MdADC在细胞分裂迅速的组织器官中表达量较高，且受低温、盐和脱水的诱导表达，表明其参与了细胞生长和这些胁迫反应。RNA凝胶印迹分析未检测到ODC的转录本。基于本研究，可以得出以下结论：（i）ODC途径在苹果中是活跃的，尽管与在其他植物物种中发现的其对应物同源的pMdODC基因的表达水平相当低;和（ii）MdADC表达与细胞生长和对低温、盐和脱水的胁迫响应相关，表明ADC是苹果中腐胺生物合成的主要生物合成途径。
Arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) are two important enzymes responsible for putrescine biosynthesis. In this study, a full-length ADC cDNA (MdADC) was isolated from apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. Meanwhile, a partial ODC (pMdODC) could be amplified only by a second RCR from the RT-PCR products, whereas a full-length ODC could not be obtained by either cDNA library screening or 5'- and 3'-RACEs, suggesting quite low expression. Moreover, D-arginine, an ADC inhibitor, caused a decrease in ADC activity and severely inhibited the growth of apple callus, which could be partially resumed by exogenous addition of putrescine, whereas alpha-difluoromethylornithine (DFMO), an inhibitor for ODC, caused the incomplete repression of callus growth without changing ODC activity. RNA gel blot showed that the expression level of MdADC was high in young tissues/organs with rapid cell division and was positively induced by chilling, salt, and dehydration, implying its involvement in both cell growth and these stress responses. By contrast, the transcript of ODC could not be detected by RNA gel blot analysis. Based on the present study, it is possible to conclude that (i) the ODC pathway is active in apple, although the expression level of the pMdODC gene homologous with its counterparts found in other plant species is quite low; and (ii) MdADC expression correlates with cell growth and stress responses to chilling, salt, and dehydration, suggesting that ADC is a primary biosynthetic pathway for putrescine biosynthesis in apple.