Related Experiment Video
Updated: Jan 16, 2026

Measurements of Physiological Stress Responses in C. Elegans
Published on: May 21, 2020
Rice E3 ligase OsRFPH2-16 acts as a negative regulator to mediate the degradation of OsPIP1;1 under salt stress
Jong Ho Kim1, Ju Hee Kim1, Geun Beom Park2
1Agriculture and Life Sciences Research Institute, Kangwon National University, Chuncheon, 24341, Republic of Korea.
Abstract:
Soil salinity has a significant negative effect on rice productivity. We characterized the Oryza sativa RING Finger Protein H2-type-16 gene (OsRFPH2-16), which plays a negative role in response to salinity. The transcript levels of OsRFPH2-16 decreased under saline conditions. OsRFPH2-16 was expressed in the ER and tonoplasts of rice protoplasts. In addition, OsRFPH2-16 exhibited E3 ligase activity in an in vitro ubiquitination assay, whereas the mutant OsRFPH2-16C188A E3 ligase did not exhibit any activity. We constructed OsRFPH2-16-overexpressing (OX-2 and OX-4) and CRISPR/Cas9-mediated OsRFPH2-16-knockout (KO-4 and KO-16) plants and evaluated their salt responses. Under salt stress, OsRFPH2-16-knockout plants exhibited improved salt tolerance, characterized by low Na+ accumulation, high non-antioxidant content, and dynamic changes in the expression levels of Na+ transporter genes, compared with wild-type and OsRFPH2-16-overexpression plants. The aquaporin OsPIP1;1, an interacting partner, was identified using yeast two-hybridization, bimolecular fluorescence complementation, and pull-down assays. Degradation of OsPIP1;1 by the E3 ligase OsRFPH2-16 via the 26S proteasome system was confirmed through an in vitro degradation assay with the inhibitor MG132. These findings support that the E3 ligase functions as a negative regulator, leading to reduced Na+ accumulation in salt stress responses.
Related Concept Videos
Stringent Response in E. coli
Other Stress Responses in Bacteria
Responses to Salt Stress
Riboswitches
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
Regulation of the Unfolded Protein Response
Global Regulatory Systems

