Canola (Brassica napus) is a widely cultivated species and provides important resources of edible vegetable oil, biodiesel production and animal feed. Seed development in Arabidopsis and canola shares a similar path: an early proliferation of endosperm to form a large seed cavity, followed by a second phase in which the embryo grows to replace the endosperm. In Arabidopsis, the seed reaches almost its final volume before the enlargement of the embryo. SHORT HYPOCOTYL UNDER BLUE1 (SHB1) is a key regulatory gene of seed development with a broad expression beyond endosperm development. By contrast, its two target genes, MINISEED3 (MINI3) and HAIKU2 (IKU2), are narrowly expressed in early developing endosperm and early embryo. We overexpressed SHB1 in canola to explore the possibility of altering seed development. As an alternative strategy, we expressed the canola IKU2 ortholog in Arabidopsis endosperm under the control of a stronger MINI3 promoter. SHB1 targeted canola orthologs of Arabidopsis MINI3 and IKU2 and caused a significantly increased seed mass. Overaccumulation of IKU2 in the early stage of Arabidopsis seed development also significantly increased the final seed mass. Our studies provide a strong case for increasing the final seed mass by manipulating endosperm proliferation at a rather early developmental stage in crops.
Bibliographical noteFunding Information:
We thank Dr Albrecht Von Arnim for kindly providing the 35S: LUC plasmid, and Dr R. Scott Mclvor for help with the LUC assay. Canola transgenic lines were generated in the Ralph M. Parsons Foundation Plant Transformation Facility at the University of California at Davis (http://ucdptf.ucdavis.edu/). This work was supported by USDA National Institution of Food and Agriculture grant 2011-67013-30150. Qing-Bin Sun was supported by a grant from National Natural Science Foundation of China (31470379).
- Canola (Brassica napus)
- HAIKU2 (IKU2)
- MINISEED3 (MINI3)
- Seed development
- Seed mass
- SHORT HYPOCOTYL UNDER BLUE1 (SHB1)
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.