High impact information on FAD7

• The Arabidopsis FAD7 gene encodes a plastid omega-3 fatty acid desaturase that catalyzes the desaturation of dienoic fatty acids in membrane lipids [1].
• In unwounded plants, exogenously applied methyl jasmonate activated the FAD7 promoter in roots, whereas it repressed FAD7 promoter activity in leaves [1].
• These observations indicate that wound-responsive expression of the FAD7 gene in aerial and subterranean parts of plants is brought about by way of different signal transduction pathways [1].
• To study wound-responsive expression of the FAD7 gene in further detail, we analyzed transgenic tobacco plants carrying the -825 Arabidopsis FAD7 promoter-beta-glucuronidase fusion gene [1].
• Inhibitors of the octadecanoid pathway, salicylic acid and n-propyl gallate, strongly suppressed the wound activation of the FAD7 promoter in roots but not in leaves or stems [1].

Biological context of FAD7

• In order to clone the fad7 gene, it was first genetically mapped relative to the flanking restriction fragment length polymorphism markers 4547 and 2488A on chromosome 3, and yeast artificial chromosomes covering the locus were identified [2].
• Except for the amino-terminal domain, the deduced amino acid sequence of the fad7 gene product had high homology to the fad3 gene product, indicating that fad7 encodes an omega-3 desaturase and that the two genes arose from a common ancestral gene [2].
• Glycerol increased SA levels and induced pathogenesis-related gene expression in all but sid2, nahG, fad7, and fad7 fad8 plants [3].
• The -825 promoter sequence conferred tissue-specific and light-responsive expression to both these reporter genes in transgenic tobacco, indicating that these expressions of the FAD7 gene were regulated mainly at the transcriptional level [4].
• Transgenic tobacco plants were produced by integration of the antisense fad7 DNA fragments under the control of a CaMV 35S promoter into the genome [5].

Anatomical context of FAD7

• The Arabidopsis FAD7 gene encodes a plastid omega-3 fatty acid desaturase that catalyzes the desaturation of dienoic fatty acids to trienoic fatty acids in chloroplast membrane lipids [6].
• Despite better membrane integrity than WT, plants having less polyunsaturation of thylakoid lipids (fad7/8 double mutant) failed to maintain greater Pn than the WT [7].

Associations of FAD7 with chemical compounds

• Mutants deficient in the chloroplast hexadecenoic acid/oleic acid desaturase (fad6) or hexadecadienoic acid/linoleic acid desaturase (fad7) had altered C6-aldehyde formation in a pattern similar to the changes in the PUFA [8].
• Taken together, wound-responsive expression of the FAD7 gene in roots is thought to be mediated via the octadecanoid pathway, whereas in leaves, jasmonate-independent wound signals may induce the activation of the FAD7 gene [1].

Other interactions of FAD7

• A series of FAD7-FAD8 chimeric genes, each encoding a functional plastidial omega-3 desaturase, were introduced into the Arabidopsis fad7fad8 double mutant [9].
• SA-induced expression of FAD7 in the npr1 mutant which is defective in an SA signaling pathway occurred to the same extent as in the wild type [6].
• Furthermore, in the sid2 mutant which lacks an enzyme required for SA biosynthesis, the expression of FAD7 was induced by ozone exposure [6].

Analytical, diagnostic and therapeutic context of FAD7

• Electron microscopy showed that chloroplast membrane ultrastructure in cor15a-FAD7 transgenic plants was unaffected by prolonged exposure to cold temperatures [10].
• RT-PCR confirmed a marked increase in FAD7 expression, in young Nicotiana tabacum (cv. Havana) plants harboring cor15a-FAD7, after a short-term exposure to cold [10].

References