High-oleate peanut mutants result from a MITE insertion into the FAD2 gene
High-oleate peanut mutants result from a MITE insertion into the FAD2 gene
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DOI：
10.1007/s00122-004-1590-3
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发表时间：
2004-05-01
影响因子：
5.4
通讯作者：
Abbott, A
中科院分区：
文献类型：
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作者：
Patel, M;Jung, S;Abbott, A
花生（Arachis hypogaea L.）据报道，依赖于两个同源的微粒体油酰-PC去饱和酶基因（ahFAD 2A或ahFAD 2B）的等位基因组成。ahFAD 2A或ahFAD 2B的酶活性足以用于正常的油酸酯表型，并且据报道，ahFAD 2B水平的显著降低和ahFAD 2A中的突变是一种化学诱导的突变体（M2-225）和一种源自天然存在的突变体（8-2122）的高油酸酯表型的原因。在这里，我们报告了在另一个化学诱导突变体（Mycogen-Flavo）和先前表征的M2-225突变体中的ahFAD 2B基因中插入相同的微型反向重复转座因子（MITE）。在这两种情况下，ahFAD 2B中的MITE插入都会引起移码，导致两种突变体中的蛋白质序列被推定截短。除了ahFAD 2A中的点突变外，该MITE在ahFAD 2B中的插入似乎是Mycogen-Flavo和M2-225突变体中高油酸表型的原因。利用MITE的序列，我们开发了一种DNA标记策略，以区分两个插入含有正常油酸花生品种（AT-108）和自然发生的，高油酸突变体8-2122的突变体。逆转录-PCR/差异消化结果揭示了在Mycogen-Flavo突变体中ahFAD 2A和ahFAD 2B基因的表达。该结果与以下观察结果形成对比：在ahFAD 2B基因中进一步3'插入MITE的M2-225突变体中，ahFAD 2B转录物大大减少。
A high-oleate trait in the cultivated peanut (Arachis hypogaea L.) was reported to rely on the allelic composition of the two homeologous, microsomal oleoyl-PC desaturase genes (ahFAD2A or ahFAD2B). The enzyme activity of either ahFAD2A or ahFAD2B is sufficient for a normal oleate phenotype, and a significant reduction in the levels of ahFAD2B and a mutation in ahFAD2A were reported to be responsible for the high-oleate phenotype in one chemically induced mutant (M2-225) and one derived from a naturally occurring (8-2122) mutant. Here, we report an insertion of the same miniature inverted-repeat transposable element (MITE) in the ahFAD2B gene in another chemically induced mutant (Mycogen-Flavo) and the previously characterized M2-225 mutant. In both cases, this MITE insertion in ahFAD2B causes a frameshift, resulting in a putatively truncated protein sequence in both mutants. The insertion of this MITE in ahFAD2B, in addition to the point mutation in ahFAD2A, appears to be the cause of the high-oleate phenotype in Mycogen-Flavo and M2-225 mutants. Utilizing sequences of the MITE, we developed a DNA marker strategy to differentiate the two insertion-containing mutants from the normal oleate peanut variety (AT-108) and the naturally occurring, high-oleate mutant 8-2122. Reverse transcript-PCR/differential digestion results reveal the expression of both ahFAD2A and ahFAD2B genes in Mycogen-Flavo mutant. This result is in contrast to the observation that ahFAD2B transcripts are greatly reduced in the M2-225 mutant having the MITE insertion further 3' in ahFAD2B gene.