Accumulation of glycinebetaine in rice plants that overexpress choline monooxygenase from spinach and evaluation of their tolerance to abiotic stress
Accumulation of glycinebetaine in rice plants that overexpress choline monooxygenase from spinach and evaluation of their tolerance to abiotic stress
复制标题
DOI：
10.1093/aob/mcl126
复制
发表时间：
2006-09-01
期刊：
影响因子：
4.2
通讯作者：
Kishitani, Sachie
中科院分区：
文献类型：
--
作者：
Shirasawa, Kenta;Takabe, Tomoko;Kishitani, Sachie
甜菜碱(GB)是一种季铵盐类化合物，是一种非常有效的相容溶质。在高等植物中，GB是由胆碱(CHO)通过甜菜碱醛(BA)合成的。胆碱单加氧酶(CMO)和甜菜碱醛脱氢酶(BADH)分别催化GB生物合成的第一步和第二步。水稻有两个BADH基因，由于缺乏CMO的功能基因，因此不积累GB。在外源BA存在的情况下，水稻植株积累了GB，这导致了水稻对盐、冷和热胁迫的显著耐受性。本研究的目的是评价和讨论内源积累的Gb对水稻的影响。中心点方法通过农杆菌介导法获得高表达菠菜CMO基因的转基因水稻植株。经Southern和Western blotting分析，用H-1-核磁共振谱定量检测水稻叶片中的Gb，并研究积累Gb的植株对非生物胁迫的耐受性。中心点关键结果表达菠菜CMO的转基因植株在0.29-0.43mmolg(-1)D.wt水平上积累Gb，且苗期对盐胁迫和温度胁迫的耐受性增强。菠菜CMO和内源BADHs的定位可能不同，或者菠菜CMO在水稻植株中的催化活性可能低于菠菜。这些可能性可能解释了转基因水稻植株中GB含量较低的原因。因此，转CMO基因水稻植株不利于GB的积累和生产力的提高。
center dot Background and Aims Glycinebetaine (GB), a quaternary ammonium compound, is a very effective compatible solute. In higher plants, GB is synthesized from choline (Cho) via betaine aldehyde (BA). The first and second steps in the biosynthesis of GB are catalysed by choline monooxygenase (CMO) and by betaine aldehyde dehydrogenase (BADH), respectively. Rice (Oryza sativa), which has two genes for BADH, does not accumulate GB because it lacks a functional gene for CMO. Rice plants accumulate GB in the presence of exogenously applied BA, which leads to the development of a significant tolerance to salt, cold and heat stress. The goal in this study was to evaluate and to discuss the effects of endogenously accumulated GB in rice.center dot Methods Transgenic rice plants that overexpressed a gene for CMO from spinach (Spinacia oleracea) were produced by Agrobacterium-mediated transformation. After Southern and western blotting analysis, GB in rice leaves was quantified by H-1-NMR spectroscopy and the tolerance of GB-accumulating plants to abiotic stress was investigated.center dot Key Results Transgenic plants that had a single copy of the transgene and expressed spinach CMO accumulated GB at the level of 0.29-0.43 mu mol g(-1) d. wt and had enhanced tolerance to salt stress and temperature stress in the seedling stage.center dot Conclusions In the CMO-expressing rice plants, the localization of spinach CMO and of endogenous BADHs might be different and/or the catalytic activity of spinach CMO in rice plants might be lower than it is in spinach. These possibilities might explain the low levels of GB in the transgenic rice plants. It was concluded that CMO-expressing rice plants were not effective for accumulation of GB and improvement of productivity.