In vivo protective effect of late embryogenesis abundant protein (ApSK3 dehydrin) on Agapanthus praecox to promote post-cryopreservation survival

Abstract

Dehydrins (DHNs), as members of the late embryogenesis abundant protein family, play critical roles in the protection of seeds from dehydration and plant adaptation to multiple abiotic stresses. Vitrification is a basic method in plant cryopreservation and is characterized by forming a glassy state to prevent lethal ice crystals produced during cryogenic storage. In this study, ApSK 3 type DHN was genetically transformed into embryogenic calluses (EC) of Agapanthus praecox by overexpression (OE) and RNA interference (RNAi) techniques to evaluate the in vivo protective effect of DHNs during cryopreservation. The cell viability showed a completely opposite trend in OE and RNAi cell lines, the cell relative death ratio was decreased by 20.0% in ApSK 3 -OE EC and significantly increased by 66.15% in ApSK 3 -RNAi cells after cryopreservation. Overexpression of ApSK 3 increased the content of non-enzymatic antioxidants (AsA and GSH) and up-regulated the expression of CAT, SOD, POD, and GPX genes, while ApSK 3 -RNAi cells decreased antioxidant enzyme activities and FeSOD, POD, and APX genes expression during cryopreservation. These findings suggest that ApSK 3 affects ROS metabolism through chelating metal ions (Cu 2+ and Fe 3+ ), alleviates H 2 O 2 and OH• excessive generation, activates the antioxidant system, and improves cellular REDOX balance and membrane lipid peroxidation damage of plant cells during cryopreservation. DHNs can effectively improve cell stress tolerance and have great potential for in vivo or in vitro applications in plant cryopreservation.