Temperature-related non-homogeneous fatty acid desaturation in sunflower (Helianthus annuus L.) seeds.
The fatty acid compositions of half-seeds and whole seeds of the temperature-dependent high-stearic-acid sunflower (Helianthus annuus L.) mutant CAS-14 were unexpectedly different. We found that there is a longitudinal gradient starting from the embryo up to the end of the cotyledon. The stearic acid content varied from 9.7 to 34.6% in seeds produced in a growth chamber (39/24 degrees C; day/night), and from 14.0 to 34.4% in seeds produced in the field during the summer season (35-40 degrees C in daylight and 20-25 degrees C at night). The gradient occurs throughout seed formation, and is due to a spatial and non-temporal regulation of stearic acid desaturation. A similar temperature-regulated behaviour, but for oleic and linoleic acid contents, was found in normal sunflower seeds. Since the deposition of oil bodies was homogeneous during seed formation, seeds showed the gradient throughout their development. This non-homogeneous distribution must be due to differences in the enzymatic pathway of de-novo fatty acid desaturation along the seed, resembling a morphogen gradient. Other high-stearic-acid mutant lines, such as CAS-3, did not show any gradient. This is the first time that a gradient and an inheritable maternal control of the fatty acid composition have been found in oilseeds.
Fernández-Moya
Valle
V
Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, Av. Padre García Tejero 4, 41012 Sevilla, Spain.
Martínez-Force
Enrique
E
Garcés
Rafael
R
D004537:Eicosanoic Acids / Q000737:chemistry / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D006368:Helianthus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D019301:Oleic Acid / Q000737:chemistry / Q000378:metabolism; D019308:Palmitic Acid / Q000737:chemistry / Q000378:metabolism; D012639:Seeds / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D013229:Stearic Acids / Q000737:chemistry / Q000378:metabolism; D013696:Temperature
D004537:Eicosanoic Acids; D005227:Fatty Acids; D013229:Stearic Acids; D019301:Oleic Acid; D019308:Palmitic Acid; C031183:stearic acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; C007547:behenic acid; C094477:arachidic acid