RmZAT10, a novel Cys2/His2 zinc finger transcription factor of Rosa multiflora, functions in cold tolerance through modulation of proline biosynthesis and ROS homeostasis

The Cys2/His2-type (C2H2) zinc finger transcription factor (TF) consists of a significant gene family that has an effect on development process regulation and a wide range of stress responses, whereas the roles and regulatory pathways of the majority of C2H2-type zinc finger TFs remain unclear. Here, we characterized a C2H2-type zinc finger TF (RmZAT10) from Rosa multiflora. RmZAT10 was mainly expressed in leaves and located in the nucleus. RmZAT10 was rapidly up-regulated during dehydration, cold as well as ABA treatment, with the maximal induction under cold stress. RmZAT10 overexpression facilitated the cold tolerance of tobacco, while gene silencing caused by virus-induced gene silencing (VIGS) of RmZAT10 within R.multiflora led to elevated cold sensitivity. Transgenic tobacco accumulated a larger amount of proline, consistent with elevated the expression level of P5CS (Δ-1-pyrroline-5-carboxylate synthetase). Nevertheless, the VIGS plant achieved the opposing trend. The treatment using 24-epi-brassinolide caused transgenic tobacco plants more sensitive to cold, while exogenous proline partially restored cold tolerance of the VIGS plants. In addition, RmZAT10 could bind specifically to and activate the promoter of RmP5CS. The above results revealed the role played by RmZAT10 in cold tolerance through the modulation of proline biosynthesis and ROS homeostasis.