The Pepper RING-Type E3 Ligase CaAIRF1 Regulates ABA and Drought Signaling via CaADIP1 Protein Phosphatase Degradation.
Ubiquitin-mediated protein modification occurs at multiple steps of abscisic acid (ABA) signaling. Here, we sought proteins responsible for degradation of the pepper (Capsicum annuum) type 2C protein phosphatase CaADIP1 via the 26S proteasome system. We showed that the RING-type E3 ligase CaAIRF1 (Capsicum annuumADIP1 Interacting RING Finger Protein 1) interacts with and ubiquitinates CaADIP1. CaADIP1 degradation was slower in crude proteins fromCaAIRF1-silenced peppers than in those from control plants.CaAIRF1-silenced pepper plants displayed reduced ABA sensitivity and decreased drought tolerance characterized by delayed stomatal closure and suppressed induction of ABA- and drought-responsive marker genes. In contrast,CaAIRF1-overexpressing Arabidopsis (Arabidopsis thaliana) plants exhibited ABA-hypersensitive and drought-tolerant phenotypes. Moreover, in these plants, CaADIP1-induced ABA hyposensitivity was strongly suppressed byCaAIRF1overexpression. Our findings highlight a potential new route for fine-tune regulation of ABA signaling in pepper via CaAIRF1 and CaADIP1.
Department of Life Science (BK21 Program), Chung-Ang University, Seoul 156-756, Korea.
Chae Woo
CW
Lim
Department of Life Science (BK21 Program), Chung-Ang University, Seoul 156-756, Korea.
Woonhee
W
Baek
Department of Life Science (BK21 Program), Chung-Ang University, Seoul 156-756, Korea sclee1972@hotmail.com.
Sung Chul
0000-0003-2725-0854
SC
Lee
D000040:Abscisic Acid / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000235:genetics; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D002212:Capsicum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018613:Microscopy, Confocal; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding; D059748:Proteolysis / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013312:Stress, Physiological; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
D010937:Plant Growth Regulators; D010940:Plant Proteins; D000040:Abscisic Acid; D044767:Ubiquitin-Protein Ligases; D010749:Phosphoprotein Phosphatases