RESUMO
A broad-specificity delta 9 desaturase gene was cloned from the cyanobacterium Anacystis nidulans. The enzyme introduces a cis-double bond at the delta 9 position of both 16 and 18 carbon saturated fatty acids linked to many kinds of membrane lipids. The gene was stably introduced into tobacco plants under transcriptional control of the cauliflower mosaic virus 35S promoter, and the enzyme was targeted into plastids by the transit peptide of the pea RuBisCO small subunit. The transgenic plants had a highly reduced level of saturated fatty acid content in most membrane lipids and exhibited a significant increase in chilling resistance.
Assuntos
Adaptação Fisiológica/genética , Temperatura Baixa , Cianobactérias/enzimologia , Ácidos Graxos Dessaturases/genética , Nicotiana/fisiologia , Fenômenos Fisiológicos Vegetais , Plantas Tóxicas , Caulimovirus/genética , Clonagem Molecular , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Estearoil-CoA Dessaturase , Nicotiana/genética , Nicotiana/metabolismoRESUMO
Three cytochrome P450 (P450) cDNAs were isolated from an eggplant hypocotyl cDNA library using eggplant CYP75 cDNA as a probe. These cDNAs have greater than 65% identity in their amino acid sequences, indicating that they belong to the same family. Comparison of these with P450 proteins from other sources showed that the protein with the greatest degree of homology is CYP71, isolated from avocado fruits (approximately 48%). We concluded that they are novel members of the CYP71 gene family (CYP71A2, 3 and 4). We have examined the level of mRNA transcripts from the CYP71 family in eggplant hypocotyl tissues and petunia flower buds, and found that the level of transcripts is developmentally regulated in the flower bud.
