Tolerance of mannitol-accumulating transgenic wheat to water stress and salinity
Tolerance of mannitol-accumulating transgenic wheat to water stress and salinity
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DOI：
10.1104/pp.102.003616
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发表时间：
2003-04-01
期刊：
影响因子：
7.4
通讯作者：
Cushman, JC
中科院分区：
文献类型：
--
作者：
Abebe, T;Guenzi, AC;Cushman, JC
以前的工作与模式转基因植物已经证明，甘露醇的细胞积累可以减轻非生物胁迫。在这里，我们表明，小麦中甘露醇生物合成的mtlD基因的异位表达提高了对水分胁迫和盐的耐受性。小麦（Triticum aestivum L.）cv Bobwhite）转化大肠杆菌的mtlD基因。使用愈伤组织和用（+ mtlD）或不用（- mtlD）mtlD转化的T1植物评价对水分胁迫和盐的耐受性。愈伤组织暴露于-1.0 MPa的聚乙二醇8，000或100 mm NaCl。T，通过停止供水或向营养培养基中添加150 mm NaCl来对植物进行胁迫。-mtlD愈伤组织的鲜重减少了40%，在聚乙二醇和37%的NaCl胁迫下的存在下。+mtlD愈伤组织的生长不受胁迫的影响。在-mtlD植物中，与+mtlD植物中的40%、8%、18%和29%相比，鲜重、干重、株高和旗叶长度分别减少70%、56%、40%和45%。盐胁迫使-mtlD植株地上部鲜重、干重、株高和剑叶长分别下降77%、73%、25%和36%，而+mtlD植株分别下降50%、30%、12%和20%。然而，甘露醇在愈伤组织和成熟的第五叶中积累的量（愈伤组织中1.7-3.7 μ mol g（-1）鲜重，叶中0.6-2.0 μ mol g（-1）鲜重）太小，不能通过渗透调节来保护免受胁迫。我们的结论是，甘露醇积累愈伤组织和成熟叶片的生长性能的改善是由于其他应力保护功能的甘露醇，虽然这项研究不能排除可能的渗透作用在植物生长区域。
Previous work with model transgenic plants has demonstrated that cellular accumulation of mannitol can alleviate abiotic stress. Here, we show that ectopic expression of the mtlD gene for the biosynthesis of mannitol in wheat improves tolerance to water stress and salinity. Wheat (Triticum aestivum L. cv Bobwhite) was transformed with the mtlD gene of Escherichia coli. Tolerance to water stress and salinity was evaluated using calli and T, plants transformed with (+ mtlD) or without (- mtlD) mtlD. Calli were exposed to -1.0 MPa of polyethylene glycol 8,000 or 100 mm NaCl. T, plants were stressed by withholding water or by adding 150 mm NaCl to the nutrient medium. Fresh weight of -mtlD calli was reduced by 40% in the presence of polyethylene glycol and 37% under NaCl stress. Growth of +mtlD calli was not affected by stress. In -mtlD plants, fresh weight, dry weight, plant height, and flag leaf length were reduced by 70%, 56%, 40%, and 45% compared with 40%, 8%, 18%, and 29%, respectively, in +mtlD plants. Salt stress reduced shoot fresh weight, dry weight, plant height, and flag leaf length by 77%, 73%,25%, and 36% in -mtlD plants, respectively, compared with 50%,30%,12%, and 20% in +mtlD plants. However, the amount of mannitol accumulated in the callus and mature fifth leaf (1.7-3.7 mumol g(-1) fresh weight in the callus and 0.6-2.0 mumol g(-1) fresh weight in the leaf) was too small to protect against stress through osmotic adjustment. We conclude that the improved growth performance of mannitol-accumulating calli and mature leaves was due to other stress-protective functions of mannitol, although this study cannot rule out possible osmotic effects in growing regions of the plant.