Seed-specific over-expression of an Arabidopsis cDNA encoding a diacylglycerol acyltransferase enhances seed oil content and seed weight
Seed-specific over-expression of an Arabidopsis cDNA encoding a diacylglycerol acyltransferase enhances seed oil content and seed weight
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DOI：
10.1104/pp.126.2.861
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发表时间：
2001-06-01
期刊：
影响因子：
7.4
通讯作者：
Taylor, DC
中科院分区：
文献类型：
--
作者：
Jako, C;Kumar, A;Taylor, DC
我们最近报道了拟南芥（生态型哥伦比亚）二酰基甘油酰基转移酶cDNA的克隆和表征（Zou等人，1999），并发现在拟南芥突变系AS 11中，在染色体II上指定为Tag 1的基因座处的甲磺酸乙酯诱导的突变由DNA中的147-bp插入组成，这导致Tag 1 cDNA中81-bp外显子2的重复。该插入突变与AS 11突变体中改变的种子脂肪酸组成、降低的二酰基甘油酰基转移酶（DGAT; EC 2.3.1.20）活性、降低的种子三酰基甘油含量和延迟的种子发育相关。插入突变对微粒体酰基辅酶A依赖性DGAT的影响在AS 11突变体中相对于野生型的DGAT活性及其底物特异性方面进行了检查。我们证明了用野生型Tag 1 DGAT cDNA的单拷贝转化突变体AS 11可以补充突变体AS 11的脂肪酸和油减少表型。更重要的是，我们第一次表明，种子特异性过表达的DGAT cDNA在野生型拟南芥增强油沉积和平均种子重量，这是与DGAT转录水平。转基因株系发育种子中DGAT活性提高了10%~ 70%。因此，本研究证实了DGAT在调节种子三酰甘油的数量和种子发育过程中的库大小方面的重要作用。
We recently reported the cloning and characterization of an Arabidopsis (ecotype Columbia) diacylglycerol acyltransferase cDNA (Zou et al., 1999) and found that in Arabidopsis mutant line AS11, an ethyl methanesulfonate-induced mutation at a locus on chromosome II designated as Tag1 consists of a 147-bp insertion in the DNA, which results in a repeat of the 81-bp exon 2 in the Tag1 cDNA. This insertion mutation is correlated with an altered seed fatty acid composition, reduced diacylglycerol acyltransferase (DGAT; EC 2.3.1.20) activity, reduced seed triacylglycerol content, and delayed seed development in the AS11 mutant. The effect of the insertion mutation on microsomal acyl-coenzyme A-dependent DGAT is examined with respect to DGAT activity and its substrate specificity in the AS11 mutant relative to wild type. We demonstrate that transformation of mutant AS11 with a single copy of the wild-type Tag1 DGAT cDNA can complement the fatty acid and reduced oil phenotype of mutant AS11. More importantly, we show for the first time that seed-specific over-expression of the DGAT cDNA in wild-type Arabidopsis enhances oil deposition and average seed weight, which are correlated with DGAT transcript levels. The DGAT activity in developing seed of transgenic lines was enhanced by 10% to 70%. Thus, the current study confirms the important role of DGAT in regulating the quantity of seed triacylglycerols and the sink size in developing seeds.