# Genome Identification of GLP Family in Korean Pine and Study on the Function of GLP1-2-6/GLP1-2-21 in Somatic Embryo Maturation

## TL;DR

This study identifies key genes in Korean pine that help with embryo development and shows that overexpressing these genes improves embryo yield and antioxidant activity.

## Contribution

The study identifies and functionally characterizes two key GLP genes involved in Korean pine somatic embryo maturation and antioxidant processes.

## Key findings

- Overexpression of PkGLP1-2-6 and PkGLP1-2-21 increases somatic embryo yield in Korean pine.
- These genes are involved in scavenging reactive oxygen species during embryo development.
- Transgenic calli show enhanced antioxidant capacity and reduced oxidative stress markers.

## Abstract

Based on prior transcriptome data, we established a core gene interaction network for Korean pine somatic embryo maturation and screened 18 core genes. These genes showed distinct differential expression in early somatic embryogenesis. In particular, PkGLP1-2-6 (Pkor04G01180) and PkGLP-1-2-21 (Pkor04G01200) were highly correlated in the network and can be regarded as key genes mediating Korean pine somatic embryo maturation. A total of 92 members of the PkGLP gene family were identified in the Korean pine genome, which can be classified into 8 subfamilies based on evolutionary relationships. Both PkGLP1-2-6 and PkGLP1-2-21 were localized in the cell membrane and nucleus. By means of a stable genetic transformation system, transgenic Korean pine calli overexpressing PkGLP1-2-6 and PkGLP1-2-21 were successfully established. The results demonstrated that the overexpression of PkGLP1-2-6 and PkGLP1-2-21 could effectively promote somatic embryogenesis and enhance the yield of somatic embryos. In the presence of exogenous abscisic acid (ABA), the somatic embryo yield of the transgenic lines was significantly higher than that of the wild-type controls. Compared with the wild-type controls, the SOD activity in the cell lines overexpressing PkGLP1-2-6 and PkGLP1-2-21 was significantly increased, whereas the activities of POD and CAT were decreased, and the contents of H2O2 and superoxide anion (O2−) were significantly reduced. These results indicate that PkGLP1-2-6 and PkGLP1-2-21 are actively involved in the reactive oxygen species (ROS) scavenging process during somatic embryogenesis of Korean pine. The overexpression of PkGLP1-2-6 and PkGLP1-2-21 contributes to enhancing the antioxidant capacity of cells, thereby increasing the yield of somatic embryos.