Functional characterization of dehydrins CpRAB and CpERD and their roles in regulating cold resistance of zucchini fruit under high relative humidity storage

The contribution of CpERD and CpRAB on cold resistance of zucchini fruit under high relative humidity (HRH) storage was studied. The results showed that higher accumulations of CpRAB and CpERD were associated with decreased chilling injury in zucchini. HRH storage maintained a higher level of CpDREB1-5 expression and further activated the transcription of CpRAB and CpERD. CpRAB and CpERD exhibited protective roles in lactate dehydrogenase activity in vitro and cell activity of transformed E.coli in vivo under stresses. In addition, CpRAB and CpERD physically interacted with the CpSOD1 and CpCAT2 of zucchini. The transient expression of CpRAB and CpERD maintained higher antioxidant activities in tobacco leaves under cold stress. Taken together, the results suggested that accumulations of CpRAB and CpERD under HRH storage enhanced the chilling resistance of zucchini fruit, which may be due to their potential protective function of enzyme activities under cold and oxidative stress.