The Mechanism Of AFP2 And COP1 Interacting To Regulate The Thermal Morphogenesis Of Arabidopsis Hypocotyls

The model plant Arabidopsis thaliana morphogenesis is affected by many environmental factors,such as light,temperature,etc.At high temperature,the plant will appear some phenomenon,such as early flowering?the thin leaf and hypocotyl elongation and so on,these biological phenomena are referred to thermomorphogenesis.At present,the research on thermomorphogenesis is widely concerned,but the upstream components of this regulation pathway remain to be identified,and its potential mechanism still needs further research.Hypocotyl is one of the important structure of higher plant growth and development.When seed germinate,hypocotyl will put the cotyledon out of the soil for photosynthesis,and to produce nutrient for late plant growth and development.At the same time,hypocotyl is the important transport corridor,such as water,mineral elements,signal molecules and other nutrients.Research reported that hypocotyl is very sensitive to the external environment changes,such as light,temperature and so on.This experiment uses Arabidopsis thaliana to explore the role of AFP2 and COP1 in the regulation of hypocotyl thermomorphogenesis mechanism.We found AFP2 restrain Arabidopsis thaliana thermomorphogenesis,the experiments indicate that at 22 ?,the hypocotyl of AFP2-ox plant is shorter compared with wild type,while the hypocotyl of afp2 mutant is longer compared with wild type,suggests that AFP2 may participate in regulating the hypocotyl growth and development.At 28 0C,we can see the similar phenomenon,the hypocotyl of AFP2-ox plant is shorter than the hypocotyl of wild type,indicating that AFP2 participates in the regulation of hypocotyl thermomorphogenesis.Therefore,we put forward the question:is there an interaction between AFP2 and COP1,and then regulate the thermomorphogenesis of Arabidopsis thaliana?We find that AFP2 and COP1 are all expressed in the nucleus and the signal can be completely merged,we also find that AFP2 and COP1 can interact with each other directly at the nucleus by bimolecular fluorescence complementation analysis.And subcellular localization experiment showed that compared to 22 ?,at 28 ?,COP1 signal is stronger and more stable.And similarly,contrast to 22 ?,at 28 ?,AFP2 signal is stronger and more stable.These results suggest that AFP2 and COP1 can interact with each other in the nucleus at 28 ?,so as to perform a certain function.We also detected the AFP2 and COP1 protein stability at high temperature,then we found that:AFP2 can inhibit COP1 protein accumulation under 28 ?,and the degradation of COP1 will cause the accumulation of HY5 in the nucleus,thereby inhibiting the elongation of hypocotyl.In conclusion,AFP2 inhibits the Arabidopsis thermomorphogenesis,mainly through AFP2 degrading COP1 and finally lead to the accumulation of HY5 in the nucleus,showing the shorter hypocotyl.This research will further help to enrich the regulatory network of thermomorphogenesis.