Identification, Expression, and Interaction Analysis of Ovate Family Proteins in Reveals a Role of PtOFP1 Regulating Drought Stress Response.

Ovate family proteins (OFPs) are a family of plant growth regulators that play diverse roles in many aspects of physiological processes. OFPs have been characterized in various plant species including tomato, , and rice. However, little is known about OFPs in woody species. Here, a total of 30 genes were identified from the genome of and were further grouped into four subfamilies based on their sequence similarities. Gene expression analysis indicated that some members of the gene family displayed tissue/organ-specific patterns. Analysis of -acting elements in the promoter as well as gene expression by hormone treatment revealed putative involvement of in hormonal response. Furthermore, PtOFP1 (Potri.006G107700) was further experimentally demonstrated to act as a transcriptional repressor. Yeast two-hybrid assay showed physical interactions of PtOFP1 with other proteins, which suggests that they might function in various cellular processes by forming protein complexes. In addition, overexpression of in conferred enhanced tolerance to PEG-induced drought stress at seedling stage, as well as a higher survival rate than the wild type at mature stage. These results provide a systematic analysis of the gene family and lay a foundation for functional characterization of this gene family.