Genetic engineering of rice capable of synthesizing fructans and enhancing chilling tolerance
Genetic engineering of rice capable of synthesizing fructans and enhancing chilling tolerance
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DOI：
10.1093/jxb/erm367
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发表时间：
2008-03-01
影响因子：
6.9
通讯作者：
Yoshida, Midori
中科院分区：
文献类型：
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作者：
Kawakami, Akira;Sato, Yutaka;Yoshida, Midori
果聚糖是基于蔗糖的水溶性果糖低聚物和聚合物，并且已经涉及保护植物免受水分胁迫。水稻（Oryza sativa L.）对低温高度敏感，不能合成果聚糖。将wft 2编码的两种小麦果聚糖合成酶蔗糖：蔗糖1-果糖基转移酶和wft 1编码的蔗糖：果聚糖6-果糖基转移酶导入水稻植株中，成功获得了积累果聚糖的水稻转化子。转wft 2和wft 1基因水稻成熟叶片分别积累了16.2 mg g（-1）FW和3.7 mg g（-1）FW的寡糖和多糖，主要由DP 7以上的菊粉寡聚物组成，主要由DP 15以上的韧皮部寡聚物组成。转wft 2基因水稻幼苗的低聚物和多糖积累量显著高于非转基因水稻幼苗，表现出较强的耐冷性。表达wft 1的水稻幼苗的寡聚物和多糖含量明显低于表达wft 2的水稻，且表达wft 1的水稻幼苗的寡聚物和多糖含量与耐冷性之间没有相关性。结果表明，转小麦果糖基转移酶基因水稻植株在成熟叶片中积累了大量的果聚糖，并在苗期表现出较强的耐冷性。这是首次报道果聚糖的积累增强了对非冻结低温的耐受性。
Fructans are water-soluble fructose oligomers and polymers that are based on sucrose, and have been implicated in protecting plants against water stress. Rice (Oryza sativa L.) is highly sensitive to chilling temperatures, and is not able to synthesize fructans. Two wheat fructan-synthesizing enzymes, sucrose:sucrose 1-fructosyltransferase, encoded by wft2, or sucrose:fructan 6-fructosyltransferase, encoded by wft1, were introduced into rice plants, and rice transformants that accumulate fructans were successfully obtained. The mature leaf blades of transgenic rice lines with wft2 or wft1 accumulated 16.2 mg g(-1) FW of oligo- and polysaccharides mainly composed of inulin oligomers of more than DP7, and 3.7 mg g(-1) FW of oligo- and polysaccharides, mainly composed of phlein oligomers of more than DP15, respectively. The transgenic rice seedlings with wft2 accumulated significantly higher concentrations of oligo- and polysaccharides than non-transgenic rice seedlings, and exhibited enhanced chilling tolerance. The oligo- and polysaccharide concentrations of seedlings expressing wft1 were obviously lower than those of lines expressing wft2, and no correlation between oligo- and polysaccharide concentrations and chilling tolerance was detected in wft1-expressing rice lines. The results suggest that transgenic rice lines expressing wheat-derived fructosyltransferase genes accumulated large amounts of fructans in mature leaf blades and exhibited enhanced chilling tolerance at the seedling stage. This is the first report owing that fructan accumulation enhanced tolerance to non-freezing low temperatures.