ABA and Ethylene
Yoo, Sang-Dong , Cho, Young-Hee , Sheen, Jen .
ETR1 Histidine Kinase Activity of Arabidopsis Promotes Plant Growth.
ETHYLENE RESPONSE 1 (ETR1) is one of five receptors for the plant hormone ethylene. The membrane receptor contains both an N-terminal ligand-binding hydrophobic domain and light signaling-implicated GAF domain. It also has a C-terminal histidine kinase (HK) domain (H353) fused with a response regulator motif (D659). Despite its well-conserved domains, the biological function or an in vivo signaling mechanism for the ETR1 HK activity remains unclear.
To examine ETR1 HK function in vivo, we have generated transgenic lines of etr1-7, an ETR1 null mutant that contained either a genomic transgene of ETR1 (gETR1) or a cDNA of ETR1 (cETR1) under the control of native ETR1 promoter. We have also generated etr1-7 lines that transformed with the cDNA of ETR1H353Q (cETR1H353Q), in which glutamine (Q) replaces the only phosphorylatable histidine (H) 353.
Quantitative triple response assays of the transgenic plants consistently show that ETR1 HK activity is dispensable in ethylene signaling. However, further growth analysis suggests that the HK activity is involved in plant growth promotion. The quantitative assay of marker gene expression indicates two-component system is activated in the growth-promoted etr1-1 and transgenic cETR1 when compared to etr1-7 and transgenic cETR1H353Q. Our cell-based functional analysis substantiates that ETR1 activates two-component system through its conserved HK (H353) and response regulator (D659) residues. Taken together, ETR1 HK activity triggers two-component system and promotes plant growth in Arabidopsis.
Log in to add this item to your schedule
Genetics 300-Ethylene signaling in plants I
1 - Harvard Medical School and Massachusetts General Hospital, Genetics and Molecular Biology, Simches, 185 Cambridge street, CPZN7250, Boston, MA, 02114, USA
2 - Harvard Medical School and Massachusetts General Hospital, Genetics and Molecular Biology
ETR1 Histidine Kinase
protein kinase signaling
Presentation Type: ASPB Minisymposium
Location: Continental B/Hilton
Date: Wednesday, July 11th, 2007
Time: 9:45 AM