Abstract:

Expansin (EXP) plays a crucial role in plant adaptation to environmental stress by regulating the relaxation of cell wall components and enhancing flexibility.The aim of this study was to investigate the characteristics of the EXP family members and their expression patterns under salt stress,and to explore the salt tolerance genes in Aquilegia coerulea.Genome-wide identification and analysis of the AcEXP family of Aquilegia coerulea was using bioinformatics methods and its expression pattern under salt stress was analysed using RNA-seq expression data and qRT-PCR.The results revealed that the entire genome of the Aquilegia coerulea contained 27 EXP genes,distributed across six chromosomes and one scaffold.The secondary structure of proteins was dominated by β-sheet and random coil.The majority of the proteins were hydrophobic,and all 27 EXPs were found in the cell wall.The phylogenetic tree showed that members of the AcEXP family were classified into four subfamilies:EXPA,EXPB,EXLA and EXLB.Members of the same subfamily possessed similar gene structure and protein conserved motifs.The AcEXP genes contained multiple elements that responded to phytohormones and stress.The transcriptome data was used to analyze the expression pattern of AcEXP under salt stress.Twenty-one EXPs responded to salt stress,but the expression patterns were different in roots and leaves.AcEXPA8/9/12,AcEXPB1,AcEXLB1 and AcEXLB2 were differentially expressed in leaves and roots.The qRT-PCR results further verified the expression pattern of AcEXP genes under salt stress.It comprehensively analyse the basic characteristics of the EXP gene family members of Aquilegia coerulea and expression changes under salt stress.The study preliminarily demonstrates that AcEXPA8/9/12,AcEXPB1,AcEXLB1 and AcEXLB2 are involved in the salt stress response process and responded positively.

Key words: Aquilegia coerulea, Expansin, Genome-wide identification, Salt stress, Expression analysis