An AP2/ERF Gene, HuERF1, from Pitaya (Hylocereus undatus) Positively Regulates Salt Tolerance

Pitaya (Hylocereus undatus) is a high salt-tolerant fruit, and ethylene response factors (ERFs) play important roles in transcription-regulating abiotic tolerance. To clarify the function ofHuERF1in the salt tolerance of pitaya,HuERF1was heterogeneously expressed inArabidopsis.HuERF1had nuclear localization whenHuERF1::GFPwas expressed inArabidopsisprotoplasts and had transactivation activity whenHuERF1was expressed in yeast. The expression ofHuERF1in pitaya seedlings was significantly induced after exposure to ethylene and high salinity. Overexpression ofHuERF1inArabidopsisconferred enhanced tolerance to salt stress, reduced the accumulation of superoxide (O-2 center dot over bar ) and hydrogen peroxide (H2O2), and improved antioxidant enzyme activities. These results indicate thatHuERF1is involved in ethylene-mediated salt stress tolerance, which may contribute to the salt tolerance of pitaya.