Genome-wide identification of poplar GSTU gene family and its PtrGSTU23 and PtrGSTU40 to improve salt tolerance in poplar

Glutathione S-transferases (GSTs) are abundant proteins encoded by a highly differentiated family of ancient genes. GSTs play an important role in plant cell detoxification and growth and development. However, their precise function in growth and response to abiotic stresses in poplar remains unclear. We have identified 81 GST genes from Populus trichocarpa, which have been categorized into 8 subfamilies. Among these subfamilies, the Tau subfamily stands out as the largest, consisting of 58 members. We isolated two Tau-like Glutathione S-transferases encoding genes, PtrGSTU23 and PtrGSTU40, and investigated the biological functions of these two genes in transgenic poplar to regulate salt tolerance in poplar. Under salt stress, reactive oxygen species (ROS) accumulate in plants, and overexpression of PtrGSTU23/40 in 84 K poplar (Populus alba × Populus glandulosa) could play a crucial role in regulating ROS scavenging by controlling the activity of plant GST enzyme. This regulation of GST enzyme activity enhanced the tolerance of poplar to salt stress. Ultimately, our findings contribute to the availability of genetic resources that can be utilized in the breeding of salt tolerance traits within fast-growing tree species.