Complementation of Seed Maturation Phenotypes by Ectopic Expression of ABSCISIC ACID INSENSITIVE3, FUSCA3 and LEAFY COTYLEDON2 in Arabidopsis

Plant Cell Physiol. 2015 Jun;56(6):1215-28. doi: 10.1093/pcp/pcv049. Epub 2015 Apr 2.


ABSCISIC ACID INSENSITIVE3 (ABI3), FUSCA3 (FUS3) and LEAFY COTYLEDON2 (LEC2), collectively the AFL, are master regulators of seed maturation processes. This study examined the role of AFL in the production of seed reserves in Arabidopsis. Quantification of seed reserves and cytological observations of afl mutant embryos show that protein and lipid but not starch reserves are spatially regulated by AFL. Although AFL contribute to a common regulation of reserves, ABI3 exerts a quantitatively greater control over storage protein content whereas FUS3 controls lipid content to a greater extent. Although ABI3 controls the reserve content throughout the embryo, LEC2 and FUS3 regulate reserves in distinct embryonic territories. By analyzing the ability of an individual ectopically expressed AFL to suppress afl phenotypes genetically, we show that conserved domains common to each component of the AFL are sufficient for the initiation of storage product synthesis and the establishment of embryo morphology. This confirms redundancy among the AFL and indicates a threshold necessary for function within the AFL pool. Since no individual AFL was able to suppress the tolerance to desiccation, mid- and late-maturation programs were uncoupled.

Keywords: Arabidopsis; B3 domain; Seed development; Starch; Storage protein; Triacylglycerol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / embryology*
  • Arabidopsis / genetics*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Biomarkers / metabolism
  • Fatty Acids / metabolism
  • Gene Regulatory Networks
  • Genetic Complementation Test*
  • Lipid Metabolism / genetics
  • Mutation / genetics
  • Phenotype
  • Plants, Genetically Modified
  • Seeds / embryology*
  • Seeds / genetics
  • Starch / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • ABI3 protein, Arabidopsis
  • Arabidopsis Proteins
  • Biomarkers
  • FUSCA3 protein, Arabidopsis
  • Fatty Acids
  • LEC2 protein, Arabidopsis
  • Transcription Factors
  • Starch