The GPCR-type G protein PeuCOLD1 of Populus euphratica conferred the ability to resist low temperature stress

Abstract

GPCR-type G proteins (GTG) play an important role in plant defense against low-temperature stress. In this study, we identified and isolated the GTG protein PeuCOLD1 from Populus euphratica. This protein may serve as a model for the cold stress adaptation system in trees. PeuCOLD1 is predominantly expressed in the roots and its expression is significantly upregulated by low temperature, freezing, and drought stress. It is localized in the cell membrane and endoplasmic reticulum, facilitating NO₃^- and Ca²⁺ influx, thereby promoting poplar growth. To examine its potential functions, we overexpressed PeuCOLD1 in triploid P. tomentosa Carrière. The transgenic poplar exhibited improved growth and increased photosynthetic activity compared to the wild-type (WT) poplar under low-temperature stress. Thus, PeuCOLD1 enhances the ability of triploid P. tomentosa Carrière to withstand low-temperature stress without hindering its growth. PeuCOLD1 also enhances the reactive oxygen scavenging enzyme capacity of poplar under low-temperature stress, leading to reduced accumulation of reactive oxygen species (ROS) and malondialdehyde by activating the antioxidant system. Additionally, the results indicated that the transgenic poplar expressed cold-responsive (COR) genes more rapidly compared to the wild-type poplar under low-temperature stress. In conclusion, our findings suggest that overexpressing PeuCOLD1 (OE-PeuCOLD1) in triploid P. tomentosa Carrière influences poplar growth by regulating NO₃^- and Ca²⁺ influx. Moreover, it enhances resistance to low-temperature stress by regulating ROS scavenging and upregulating COR gene expression.