Analysis of Perilla frutescens ERF family transcription factors and functional analysis of salt tolerance of key gene PfABI4

As one of the largest transcription factor families, ERF family are widely involved in plant growth and development. ABI4 is a key ERF transcription factor in the ABA signaling pathway and is involved in seed dormancy and germination. However, it is currently unclear how many ERF family members are present in Perilla frutescens and whether PfABI4 plays a role in seed germination and salt stress. In this study, a total of 186 PfERF family members were identified in the P. frutescens genome and divided into 2 branches (ERF and DREB) based on their phylogenetic relationships, conserved motifs, and gene structures. The cis-regulatory elements and expression pattern analysis revealed that PfERF genes are extensively involved in growth and development, abiotic stress, photoperiod and metabolic processes of P. frutescens. PfABI4 was expressed only in leaves and seeds and was induced by ABA and salt. PfABI4 is localized in the nucleus and cell membrane. PfABI4 negatively regulates seed germination, a process that may be accomplished through the inhibition of ARR6, ARR7, and ARR15. In addition, PfABI4 also negatively regulated the expression of VTC2, APX1, GalDH and GLDH, thereby regulating plant tolerance to salt stress. Taken together, this research will help identify novel candidate genes that respond to stress for the mining and innovative utilization of germplasm resources of the oil bearing crop P. frutescens.