Two high linolenic mutants of Arabidopsis thaliana contain megabase-scale genome duplications encompassing the FAD3 locus.
Two high linolenic mutants of Arabidopsis thaliana contain megabase-scale genome duplications encompassing the FAD3 locus.
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DOI：
10.1111/j.1365-313x.2011.04742.x
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发表时间：
2011-12
期刊：
影响因子：
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通讯作者：
C. O'Neill;D. Baker;G. Bennett;J. Clarke;I. Bancroft
中科院分区：
文献类型：
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作者：
C. O'Neill;D. Baker;G. Bennett;J. Clarke;I. Bancroft
了解种子贮藏油生物合成过程中脂肪酸去饱和的定量控制已成为研究的优先领域，因为其对人类健康和工业应用中矿物油替代品的重要性。我们分析了拟南芥中两个突变体的基因组结构，这两个突变体在其种子油中表现出ω-3多不饱和脂肪酸亚麻酸的含量显著升高。在一个例子中，rfc 4，来自2号染色体的总计约2 Mb的序列被复制并插入3号染色体。在另一个突变体，ife，染色体2序列总计约1.4 Mb已被复制，并插入到一个连锁的位置。在这两种情况下，重复包括FAD 3基因座，其编码亚油酸去饱和酶，负责亚麻酸的生物合成以在种子储存油中积累。结果表明，诱变剂如快中子（用于诱导rfc 4）和T-DNA（用于诱导ife，与品系中存在的T-DNA不相关）可导致非常大的基因组片段的复制。他们还表明，增加含有FAD 3的基因组区域的剂量会导致种子油中亚麻酸含量的增加。因此，在油料作物中重复FAD 3直向同源物的筛选方法可能是一种合适的方法，用于鉴定种质，以培育在其产生的油中具有增加的亚麻酸比例的品种。
Understanding the quantitative control of fatty acid desaturation during the biosynthesis of seed storage oil has become a priority area for research, as a consequence of its importance for both human health and the substitution of mineral oil for industrial applications. We have analysed the genome structure of two mutants in Arabidopsis thaliana that show substantially elevated content of the omega-3 polyunsaturated fatty acid linolenic acid in their seed oil. In one, rfc4, sequences totalling approximately 2 Mb from chromosome 2 have been duplicated and inserted into chromosome 3. In the other mutant, ife, chromosome 2 sequences totalling approximately 1.4 Mb have been duplicated and inserted into a linked position. In both cases, the duplications encompass the FAD3 locus, which encodes the linoleate desaturase responsible for the biosynthesis of linolenic acid for accumulation in seed storage oil. The results show that mutagens such as fast neutrons (used for the induction of rfc4) and T-DNA (used for the induction of ife, which is not linked to the T-DNA present in the line) can result in the duplication of very large genome segments. They also show that increasing the dosage of the FAD3-containing genomic region results in an increase in the linolenic acid content of seed oil. Consequently, screening methods for duplication of FAD3 orthologues in oil crops may be an appropriate approach for the identification of germplasm for breeding varieties with increased proportions of linolenic acid in the oil that they produce.