Untitled

Abstract

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.

Differences in cold tolerance and expression of two fatty acid desaturase genes in the leaves between fingered citron and its dwarf mutant

“…Three replicates were averaged and the standard deviation is shown in cotton (Kargiotidou et al 2008), PoleFAD2 in purslane (Teixeira et al 2009) and PlFAD2 in Phaseolus lunatus (Zhang et al 2011) were induced by cold stress. FAD8 was also induced by low temperatures in A. thaliana (Gibson et al 1994), maize (Berberich et al 1998), rice (Wang et al 2006), Descurainia sophia (Tang et al 2007) and purslane (Teixeira et al 2010). Our results showed that there was a greater expression of two FAD genes during 6°C treatment in fingered citron leaves (Fig.…”

“…The genomic sequence of CmsFAD8 was 2,751 bp and contained eight exons and seven introns (Fig. 3), similar to FAD8 genes from other higher plants (Gibson et al 1994;Berberich et al 1998).…”

Responses of Unsaturated Fatty Acid in Membrane Lipid and Antioxidant Enzymes to Chilling Stress in Sweet Sorghum (Sorghum bicolor (L.) Moench) Seedling

“…Chilling stress inhibits photosynthesis by the process of photoinhibition (Xu et al, 1999;Zhang et al, 2011). Previous research suggested that plant tolerance to chilling is dependent on unsaturated fatty acid levels (Berberich et al, 1998;Mikami & Murata, 2003). In the present study, we investigated the effects of chilling stress on the photosynthesis, antioxidant enzyme and unsaturated fatty acids in membrane lipids on seedlings growth of two sweet sorghum inbred lines.…”

Increases of Unsaturated Fatty Acids in Membrane Lipids Protects Photosystem II from Photoinhibition under Salinity in Different Halophytes

“…Recent researches have found that high salt levels increase membrane lipids' unsaturated fatty acid contents in halophytes but not in A. thaliana (Table 4).As known o all, among halophytes, 18:3 is the predominant unsaturated fatty acid during NaCl stress. The x-3 desaturases transgenic tobacco improved resistance ability to salt and drought stress (Zhang et al, 2005), which implies the salt and drought tolerance of plant depends on the levels of unsaturated fatty acids (Berberich et al, 1998;Mikami & Murata, 2003). Synechocystis mutants, which lacked the activity of x-6 and x-3 desaturase, reduced the resistant ability to salt stress (Allakhverdiev et al, 2001).…”