Genome-wide identification and characterization of ACBP gene family in Populus reveal salinity alkali-responsive profiles

Acyl-CoA-binding proteins (ACBPs) are important for the transport of acyl groups for macromolecular biosynthesis involved in plant growth, development, and diverse stress (e.g., cold, drought, salinity, and heavy metals) responses. Here, we report the phylogeny and characteristics of the ACBP family in the woody plant Populus trichocarpa . Eight genes encoding ACBP proteins were identified, and they are distributed on eight chromosomes in P. trichocarpa. These PtACBP genes were divided into four subgroups according to gene structure, conserved motifs and phylogenetic relationship. Promoter analysis revealed that cis -elements were related to stress response, phytohormone response, and physical and reproductive growth regulation. Expression levels of PtACBP genes varied among different organs, with the highest expression in leaves and the lowest in stems. Quantitative real-time PCR (qRT-PCR) analysis showed that under salinity-alkali stresses (i.e., 200 mM NaCl, 75 mM Na 2 CO 3 , and 100 mM NaHCO 3 ), four ( PtACBP1 , PtACBP3 , PtACBP4 and PtACBP8 ) of eight PtACBP genes were significantly induced in roots and leaves. These data provide a comprehensive analysis of the ACBPs family in P. trichocarpa , which could be useful for gene function analyses.