Low-temperature-induced transcription factors in grapevine enhance cold tolerance in transgenic Arabidopsis plants.

We report the characterization of low-temperature-induced transcription factors in grapevine (Vitis vinifera). Four transcription factors were identified in low-temperature-treated grapevine. The expression of V. vinifera C-repeat-binding factors, VvCBF2, VvCBF4, and VvCBFL, and V. vinifera B-box-type zinc finger protein, VvZFPL, was immediately induced and upregulated in leaves by the low-temperature treatment. Similar induction of the gene expression was observed in low-temperature-treated stems and flowers, although VvZFPL was constitutively expressed in flowers. Tendrils expressed all the four genes constitutively. In berry skin, VvCBF2 and VvCBFL were induced by the low-temperature treatment before the onset of véraison, while only VvCBF2 was induced under the low-temperature condition after the onset of véraison. The overexpression of VvCBF2 and VvZFPL in Arabidopsis plants led to longer hypocotyls than the control plants. The rosette leaves of these plants were smaller and had lower chlorophyll contents than those of the control plants, resulting in a pale green color. Finally, the VvCBF2- and VvZFPL-overexpressing plants revealed growth retardation. These results suggest that VvCBF2 and VvZFPL may affect photomorphogenesis and growth in grapevine. Meanwhile, no morphological changes were detected in the VvCBF4- and VvCBFL-overexpressing plants. The cold tolerance test demonstrated that all of the overexpressing plants remained viable and noticeably healthy compared with the control plants even after exposure to severe cold treatment, suggesting that VvCBF2, VvCBF4, VvCBFL, or VvZFPL may enhance cold tolerance in grapevine.