Evidence that norflurazon affects chloroplast lipid unsaturation in soybean leaves (Glycine max L.).
Norflurazon is a bleaching herbicide known to block carotenoid biosynthesis by inhibiting phytoene desaturase activity. Soybean plants were treated with norflurazon, and we examined the effects on the desaturation of lipid molecular species in leaves using ammonium [1-(14)C] oleate labeling. In monogalactosyldiacylglycerol (MGDG), the main chloroplast lipid, a decrease in 18:3/18:3 molecular species and an increase in its precursors 18:2/18:3 and 18:2/18:2 were observed suggesting that the omega(3) FAD7 desaturase activity in planta was inhibited by norflurazon. The in vitro activity of MGDG synthase was also inhibited by 69%. In contrast, the amount of 18:3/18:3 molecular species of phosphatidylcholine (PC) in the extraplastid compartment increased. The observed increase in in vitro lysoPC-acyltransferase activity and activation of desaturation of [1-(14)C] oleate suggest that extraplastid omega(3)FAD3 desaturase was activated. Analysis of the expression of omega(3) FAD3 and omega(3) FAD7 genes in norflurazon treated plants indicate that omega(3) FAD7 and omega(3) FAD3 desaturases are controlled at the post-transcriptional level.
Abrous-Belbachir
Ouzna
O
Université des Sciences et de la Technologie Houari Boumedienne, Faculté des Sciences Biologiques, Bab Ezzouar, Alger, Algeria.
De Paepe
Rosine
R
Trémolières
Antoine
A
Mathieu
Chantal
C
Ad
Fatiha
F
Benhassaine-Kesri
Ghouziel
G
D002736:Chloroplasts / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000378:metabolism; D006540:Herbicides / Q000494:pharmacology*; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011724:Pyridazines / Q000494:pharmacology*; D013025:Glycine max / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
D006540:Herbicides; D008055:Lipids; D010940:Plant Proteins; D011724:Pyridazines; D044943:Fatty Acid Desaturases; C008677:norflurazone