Berberich T, Harada M, Sugawara K, Kodama H, Iba K, Kusano T
Biotechnology Institute, Akita Prefectural College of Agriculture, Japan.
Plant Mol Biol. 1998 Jan;36(2):297-306. doi: 10.1023/a:1005993408270.
We have isolated two maize cDNAs and the corresponding genes encoding fatty acid desaturase with Arabidopsis thaliana FAD7 gene as a probe. They shared almost 90% identity at DNA sequence level. Northern analysis revealed that both genes are expressed in leaves, but not in roots at normal temperature- and low temperature-growth condition. The overall level of these transcripts are elevated upon exposure to low temperature. The tissue-specific expression and DNA sequence data indicate that both genes encode plastidic omega-3 fatty acid desaturases. One of them is expressed exclusively at normal temperature but not at 5 degrees C, whereas the other is expressed inversely. We, therefore, termed them ZmFAD7 and ZmFAD8, respectively. Among other stresses, high-salt treatment induced the accumulation of the ZmFAD7 and ZmFAD8 transcripts in roots but drought had no effect on their expression. Cycloheximide induced the accumulation of the ZmFAD7 transcript in roots. The genomic clones of ZmFAD7 and ZmFAD8 consist of 8 exons and 7 introns as same as in the cases of A. thaliana FAD7 and FAD8 genes and the sizes of the 6 internal exons were identical among them. A phylogenetic analysis of ZmFAD7, ZmFAD8 amino acid sequences and those originated from other plant species is also presented.
我们以拟南芥FAD7基因为探针，分离出了两个玉米cDNA以及相应的编码脂肪酸去饱和酶的基因。它们在DNA序列水平上有近90%的同一性。Northern分析表明，在正常温度和低温生长条件下，这两个基因在叶片中表达，但在根中不表达。暴露于低温时，这些转录本的总体水平会升高。组织特异性表达和DNA序列数据表明，这两个基因都编码质体ω-3脂肪酸去饱和酶。其中一个仅在正常温度下表达，在5摄氏度时不表达，而另一个则相反表达。因此，我们分别将它们命名为ZmFAD7和ZmFAD8。在其他胁迫中，高盐处理诱导ZmFAD7和ZmFAD8转录本在根中积累，但干旱对它们的表达没有影响。环己酰亚胺诱导ZmFAD7转录本在根中积累。ZmFAD7和ZmFAD8的基因组克隆与拟南芥FAD7和FAD8基因一样，由8个外显子和7个内含子组成，其中6个内部外显子的大小相同。本文还对ZmFAD7、ZmFAD8氨基酸序列以及来自其他植物物种的氨基酸序列进行了系统发育分析。
