Objective In order to elucidate the functions of the ATP-binding cassette (ABC) protein in Sedum alfredii, a Cd hyperaccumulator, the bioinformatics analysis and expression pattern study were performed on Sa12F279 belonging to ABC protein family.

MethodsA local blast was carried out in the transcriptomic datasets of S. alfredii and produced a transcript categorized to ABC protein family. Further bioinformatics analysis was conducted on the phylogenetic clustering, the protein domain structures and classification of possible interaction proteins. Quantitative real-time PCR (qRT-PCR) was applied to uncover the expression patterns of Sa12F279 in the root under drought, salt, abscisic acid stresses.

Result In the present work, a gene belonging to C subfamily of ABCs was identified in S. alfredii using local blast and designated as Sa12F279. The length of Sa12F279 open reading frame was 4 497 bp, coding a protein of 1 498 amino acids with pI being 6.92. The phylogenetic analysis showed that Sa12F279 was clustered with the C-subfamily of ABC protein, exhibiting uniform domain structure of TMD-NBD-TMD-NBD. Co-expression network analysis indicated that Sa12F279 served as hub genes mostly associated with metabolic process (39.8%), cellular process (29.3%), biological regulation (10.2%) and transporter activity (7.1%). The expression data from the transcriptomic datasets showed that Sa12F279 was suppressed by Cd stress in the three tissues (root, stem and leaf) at the sampling points of 24 h and 96 h. Transcriptional expression profiles responsive to drought, salt, abscisic acid (ABA) stress illustrated different response tendencies showing moderate induction. Under the treatment of ABA, the expression of Sa12F279 exhibited the tendency of decrease to elevation. Under the salt stress, Sa12F279 was up-regulated at the late stage of treatment while under the drought stress, Sa12F279 displayed the irregular tendency of elevation-decrease-elevation.

Conclusion Based on the studies above, the authors characterize a gene named Sa12F279 belonging to the ABC protein family in S. alfredii and performs a comprehensive analysis including phylogenetic analysis, protein structure and co-expression network. Meanwhile, the expression profiles under different abiotic stress are also uncovered. The results could provide reference for the further studies on the ABC protein family.