Plant sterol-C24-methyl transferases: different profiles of tobacco transformed with SMT1 or SMT2.
Higher plant cells contain a mixture of 24-desmethyl, 24-methyl(ene), and 24-ethyl(idene) sterols in given proportions according to species but also to cell type. As a first step to investigate the function of such sterol compositions in the physiology of a plant, we have illustrated in the present work the coexistence of two distinct (S)-adenosyl-L-methionine sterol-C24-methyltransferases (SMT) in transgenic Nicotiana tabacum L. Indeed, modulation of the expression of the tobacco gene SMT1-1, which encodes a cycloartenol-C24-methyltransferase, results in variations of the proportion of cycloartenol and a concomitant effect on the proportion of 24-ethyl sterols. Overexpression in tobacco of the Arabidopsis thaliana (L.) Heynh. gene SMT2-1 which encodes a 24-methylene lophenol-C24(1)-methyltransferase, results in a dramatic modification of the ratio of 24-methyl cholesterol to sitosterol associated with a reduced growth, a topic discussed in the present work.
Schaeffer
A
A
Institute de Biologie Moléculaire des Plantes, Département Biosynthèse et Fonctions des Isoprenoïdes, Institut de Botanique, Strasbourg, France.
Bouvier-Navé
P
P
Benveniste
P
P
Schaller
H
H
D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D002784:Cholesterol / Q000031:analogs & derivatives / Q000378:metabolism; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism*; D010840:Phytosterols; D030821:Plants, Genetically Modified / Q000201:enzymology* / Q000254:growth & development; D010947:Plants, Toxic; D012855:Sitosterols / Q000378:metabolism; D013261:Sterols / Q000378:metabolism*; D014026:Nicotiana / Q000201:enzymology* / Q000254:growth & development
D010840:Phytosterols; D012855:Sitosterols; D013261:Sterols; C021273:campesterol; C025473:gamma-sitosterol; D002784:Cholesterol; C409822:24-methylene-lophenol-C24-methyltransferase; D008780:Methyltransferases; C019609:S-adenosyl-L-methionine-cycloartenol methyltransferase; C022670:delta 24-sterol methyltransferase