Betaine Aldehyde Dehydrogenase in Sorghum (Molecular Cloning and Expression of Two Related Genes)
Betaine Aldehyde Dehydrogenase in Sorghum (Molecular Cloning and Expression of Two Related Genes)
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DOI：
10.1104/pp.110.4.1301
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发表时间：
1996-04
期刊：
影响因子：
6.1
通讯作者：
A. Wood;H. Saneoka;D. Rhodes;R. Joly;P. Goldsbrough
中科院分区：
文献类型：
--
作者：
A. Wood;H. Saneoka;D. Rhodes;R. Joly;P. Goldsbrough
合成和积累甜菜碱的能力在被子植物中广泛存在，并被认为有助于耐盐和耐旱。在植物中，甘氨酸甜菜碱是由胆碱单加氧酶和甜菜碱醛脱氢酶（BADH）催化胆碱经中间体甜菜碱醛两步氧化合成的。从高粱（Sorbitum bicolor）中分离到两个甜菜碱醛脱氢酶cDNA克隆BADH 1和BADH 15。BADH 1是一个1391 bp的截短cDNA。BADH 15是一个全长cDNA克隆，长度为1812 bp，预测编码53.6 kD的蛋白质。BADH 1和BADH 15的氨基酸序列与其它植物BADH有很高的同源性。研究了水分亏缺对开花前高粱叶片BADH mRNA表达、叶片水分关系和甜菜碱积累的影响。BADH 1和BADH 15的mRNA都诱导水分亏缺和他们的表达与观察到的甜菜碱积累。在胁迫17 d的过程中，高粱植株的叶水势达到-2.3 MPa。在响应水分亏缺，甘氨酸甜菜碱水平增加26倍，脯氨酸水平增加108倍。在严重胁迫的植物中，脯氨酸占总游离氨基酸库的60%以上。这些兼容的溶质的积累显着有助于渗透势，并允许0.405 MPa的最大渗透调节。
The ability to synthesize and accumulate glycine betaine is wide-spread among angiosperms and is thought to contribute to salt and drought tolerance. In plants glycine betaine is synthesized by the two-step oxidation of choline via the intermediate betaine aldehyde, catalyzed by choline monooxygenase and betaine aldehyde dehydrogenase (BADH). Two sorghum (Sorghum bicolor) cDNA clones, BADH1 and BADH15, putatively encoding betaine aldehyde dehydrogenase were isolated and characterized. BADH1 is a truncated cDNA of 1391 bp. BADH15 is a full-length cDNA clone, 1812 bp in length, predicted to encode a protein of 53.6 kD. The predicted amino acid sequences of BADH1 and BADH15 share significant homology with other plant BADHs. The effects of water deficit on BADH mRNA expression, leaf water relations, and glycine betaine accumulation were investigated in leaves of preflowering sorghum plants. BADH1 and BADH15 mRNA were both induced by water deficit and their expression coincided with the observed glycine betaine accumulation. During the course of 17 d, the leaf water potential in stressed sorghum plants reached -2.3 MPa. In response to water deficit, glycine betaine levels increased 26-fold and proline levels increased 108-fold. In severely stressed plants, proline accounted for >60% of the total free amino acid pool. Accumulation of these compatible solutes significantly contributed to osmotic potential and allowed a maximal osmotic adjustment of 0.405 MPa.