Abstract：Abstract Zinc finger proteins (ZFPs) are a class of transcriptional factors that play important roles in growth, development and stress responses in plants. Finding more genes which have key function in cold stress response can give support for cold tolerance breeding in Eucalyptus trees with molecular assisted selection. A zinc finger protein gene induced under treatment at low temperature was screened in Eucalyptus grandis. The gene was named EgrZFP7. EgrZFP7 protein structure and its function were analyzed in the research.This gene is a classical C2H2 type zinc finger protein gene. The protein sequence it encoding contains 2 zinc finger motifs, 1 L-Box motif and 1 EAR motif. EgrZFP7∷GFP vector was constructed and subcellular localization of EgrZFP7 was verified by bombardment of onion epidermis with a gene gun.The result showed that it localized in nuclear. The vector of 35S∷EgrZFP7 was also constructed and transformed into Arabidopsis thaliana. Two homozygoteslines of EgrZFP7-OX1 and EgrZFP7-OX2 were obtained. Under normal growth condition, the 2 EgrZFP7 over-expression lines showed more lateral roots and the length of lateral roots were also longer than that of the wide type. However, when EgrZFP7-OX1 and EgrZFP7-OX2 were treated at -8 ℃ for 3 d, then recovered for 3 d under normal temperature, the speed of growth recovery of over-expression lines was slower than that of the wild type. Finally, death percentage of total seedlings EgrZFP7-OX1 and EgrZFP7-OX2 lines were obviously higher than that of the wild type, implying that over-expression of EgrZFP7 could increase sensitivity to low temperature in seedlings. A protein, EgrERF4 (Eucalyptus grandis ethylene response factor 4), which can interact with EgrZFP7 was screened and verified from Yeast Two Hybrid Library. It could be concluded that EgrZFP7 possibly play a role in gene regulation in cold stress response through interact with EgrERF4 in Eucalyputs grandis. The present study gives more information to learn the mechanism of cold stress response in Eucalyptus.
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