Open AccessTwo B3 domain transcriptional repressors prevent sugar-inducible expression of seed maturation genes in Arabidopsis seedlings
Author(s) -
Hironaka Tsukagoshi,
Atsushi Morikami,
Kenzo Nakamura
Publication year - 2007
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0607940104
Subject(s) - seedling , cotyledon , arabidopsis , biology , sugar , hypocotyl , germination , arabidopsis thaliana , storage protein , sucrose , leafy , gene expression , gene , imbibition , transcription factor , botany , mutant , repressor , microbiology and biotechnology , biochemistry
During development of plant seeds, embryos import nutrients and store massive amounts of reserves. Seed reserves are rapidly degraded and mobilized to support seedling development after germination. HIGH-LEVEL EXPRESSION OF SUGAR-INDUCIBLE GENE 2 (HSI2) ofArabidopsis thaliana is a B3 DNA-binding domain protein that represses the transcription of sugar-inducible reporter gene. Although disruption ofHSI2 orHSI2-Like 1 (HSL1 ) did not affect growth, seeds with disruption of bothHSI2 andHSL1 (KK mutant) developed abortive seedlings that stopped growing 7–9 days after imbibition.KK seedlings developed swollen hypocotyls that accumulated seed storage proteins and oil on medium containing sucrose or other metabolizable sugars, and calluses developed fromKK seedlings also accumulated seed storage reserves. The expression of seed maturation genes, which include LEAFY COTYLEDON-type master regulators, inKK seedlings depended on the concentration of sucrose, suggesting that sugar controls the expression of seed maturation genes. Our results suggest that HSI2 and HSL1 repress the sugar-inducible expression of the seed maturation program in seedlings and play an essential role in regulating the transition from seed maturation to seedling growth.