The seed maturation program is repressed during germination and seedling development so that embryonic genes are not expressed in vegetative organs. In Arabidopsis, B3 domain transcriptional repressors VAL play an essential role in the developmental stage. However, much less is known about the function of these B3 genes in cereal.
A team of researchers led by Dr. Chengcai Chu in the Institute of Genetics and Developmental Biology, the Chinese Academy of Sciences has now revealed some of its mechanisms.
Chu and his colleagues isolated a rice mutant named as germination-defective1 (gd1) through a large scale screening of rice T-DNA mutant population. Their analysis showed that GD1 encodes a B3 domain-containing transcription factor with repressor activity. It can directly repress the gibberellin (GA) inactivation gene expression and indirectly stimulate a large subset of seed maturation gene expressions, which results in the decreased endogenous GA level. In addition, GD1 is also involved in sugar response.
These data indicate that GD1 participates directly or indirectly in regulating GA and carbohydrate homeostasis, and further regulates rice seed and seedling development.
AUTHOR CONTACT:
Chengcai Chu, Ph.D.
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
