Characterization of the Polyamine Biosynthetic Pathways and Salt Stress Response in Brachypodium distachyon
Characterization of the Polyamine Biosynthetic Pathways and Salt Stress Response in Brachypodium distachyon
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DOI：
10.1007/s00344-017-9761-z
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发表时间：
2018-06
影响因子：
4.8
通讯作者：
Yoshihiro Takahashi;M. Tahara;Yuki Yamada;Yuka Mitsudomi;K. Koga
中科院分区：
文献类型：
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作者：
Yoshihiro Takahashi;M. Tahara;Yuki Yamada;Yuka Mitsudomi;K. Koga
为了表征二穗短柄草中多胺 (PA) 的生物合成途径，我们分析了不同器官中的基因表达模式和 PA 含量。检测到三种主要的 PA——腐胺 (Put)、亚精胺 (Spd) 和精胺 (Spm)，但在所有检查的组织中，热精胺 (T-Spm) 均低于高效液相色谱的灵敏度极限，尽管 ACL5 基因（即 T-Spm 合成基因）的表达得到了证实。在叶片中，Put是PA含量最高的，其积累水平是Spd和Spm的3倍多。相比之下，其他器官中的主要 PA 是 Spd。在正常生长条件下，精氨酸脱羧酶（ADC）基因表达模式与 Put 含量之间存在高度相关性。这些结果表明 Put 通常是通过 ADC 途径合成的。我们还分析了盐胁迫反应，并证实所有 PA 生物合成基因都是由 NaCl 处理诱导的。此外，Spm在盐胁迫条件下高度积累。最近，T-Spm 被证明可以通过降低保守的上游开放阅读框 (uORF) 的抑制作用来增强拟南芥 SAC51 家族 mRNA（至少是 SAC51 和 SACL1）的翻译。通过数据库分析，从B. B.中鉴定出3个和5个SAC51家族基因。分别是二穗花和玉米。然而，这些基因与拟南芥中的SACL3关系最为密切，并且其中一些基因的普遍保守的uORF序列尚未得到证实。因此，T-Spm 在单子叶植物中的功能可能与在拟南芥中的不同。
To characterize polyamine (PA) biosynthetic pathways inBrachypodium distachyon, we analyzed the gene-expression patterns and PA contents in various organs. Three major PAs—putrescine (Put), spermidine (Spd), and spermine (Spm)—were detected, but thermospermine (T-Spm) was below the sensitivity limit of high-performance liquid chromatography in all tissues examined, although expression of theACL5gene, which is known as the T-Spm synthesis gene, was confirmed. In leaves, Put was the most abundant PA, and its level of accumulation was more than three times greater than those of Spd and Spm. In contrast, the primary PA in other organs was Spd. A high correlation was observed betweenarginine decarboxylase(ADC) gene-expression patterns and Put contents under normal growth conditions. These results indicate that Put is normally synthesized through the ADC pathway. We also analyzed salt stress responses and confirmed that all PA biosynthesis genes are induced by NaCl treatment. Moreover, Spm highly accumulated under salt stress conditions. Recently, T-Spm was shown to enhance the translation ofArabidopsis SAC51family mRNAs, at leastSAC51andSACL1, by reducing the inhibitory effect of the conserved upstream open reading frame (uORF). Through database analysis, three and fiveSAC51family genes were identified fromB. distachyonandZea mays, respectively. However, these genes are most closely related toSACL3inArabidopsis, and the commonly conserved uORF sequence was not confirmed for some of these genes. Therefore, the function of T-Spm in monocotyledonous plant species might be different from that inArabidopsis.