Abstract

Oat (Avena sativa L.) is unusual among the cereal grains in storing high amounts of oil in the endosperm; up to 90% of total grain oil. By using oat as a model species for oil metabolism in the cereal endosperm, we can learn how to develop strategies to redirect carbon from starch to achieve high-oil yielding cereal crops. Carbon precursors for lipid synthesis were compared in two genetically close oat cultivars with different endosperm oil content (about 6% and 10% of grain dw, medium-oil; MO, and high-oil; HO cultivar, respectively) by supplying a variety of ¹⁴C-labelled substrates to the grain from both up- and downstream parts of glycolysis, either through detached oat panicles in vitro or by direct injection in planta. When supplied by direct injection, ¹⁴C from acetate was identified to label the lipid fraction of the grain to the highest extent among substrates tested; 46% of net accumulated ¹⁴C, demonstrating its applicability as a marker for lipids in the endosperm. Time course analyses of injected ¹⁴C acetate during grain development suggested a more efficient transfer of fatty acids from polar lipids to triacylglycerol in the HO as compared to the MO cultivar, and turnover of triacylglycerol was suggested to not play a major role for the final oil content of oat grain endosperm despite the low amount of protective oleosins in this tissue. Moreover, availability of light was shown to drastically affect grain net carbon accumulation from ¹⁴C-sucrose when supplied through detached panicles for the HO cultivar.

Keywords

Carbon partitioning; Cereals; Endosperm; Fatty acid; Oat grain; Oil; Starch

Published in

Plant Physiology and Biochemistry
2014, Volume: 83, pages: 346-355

SLU Authors

• Grimberg, Åsa

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Plant Biotechnology


Publication identifier

DOI: https://doi.org/10.1016/j.plaphy.2014.08.018

Permanent link to this page (URI)

https://res.slu.se/id/publ/60928