OsABF1 Represses Gibberellin Biosynthesis to Regulate Plant Height and Seed Germination in Rice (Oryza sativa L.)
Liqun Tang +, Huayu Xu +, Yifeng Wang , Huimei Wang , Zhiyong Li, Xixi Liu, Yazhou Shu , Guan Li , Wanning Liu, Jiezheng Ying,Xiaohong Tong ,Jialing Yao, Wenfei Xiao , Shaoqing Tang *, Shen Ni *，Jian Zhang *
International Journal of Molecular Sciences
10.3390/ijms222212220。
Abstract
Gibberellins (GAs) are diterpenoid phytohormones regulating various aspects of plant
growth and development, such as internode elongation and seed germination. Although the GA
biosynthesis pathways have been identified, the transcriptional regulatory network of GA homeostasis still remains elusive. Here, we report the functional characterization of a GA-inducible
OsABF1 in GA biosynthesis underpinning plant height and seed germination. Overexpression of
OsABF1 produced a typical GA-deficient phenotype with semi-dwarf and retarded seed germination.
Meanwhile, the phenotypes could be rescued by exogenous GA3
, suggesting that OsABF1 is a key
regulator of GA homeostasis. OsABF1 could directly suppress the transcription of green revolution
gene SD1, thus reducing the endogenous GA level in rice. Moreover, OsABF1 interacts with and
transcriptionally antagonizes to the polycomb repression complex component OsEMF2b, whose
mutant showed as similar but more severe phenotype to OsABF1 overexpression lines. It is suggested
that OsABF1 recruits RRC2-mediated H3K27me3 deposition on the SD1 promoter, thus epigenetically
silencing SD1 to maintain the GA homeostasis for growth and seed germination. These findings shed
new insight into the functions of OsABF1 and regulatory mechanism underlying GA homeostasis
in rice.