Genomic Survey, Characterization, and Expression Profile Analysis of the SBP Genes in Pineapple ( L.).

Gene expression is regulated by transcription factors, which play many significant developmental processes. SQUAMOSA promoter-binding proteins (SBP) perform a variety of regulatory functions in leaf, flower, and fruit development, plant architecture, and sporogenesis. 16 genes were identified in pineapple and were divided into four groups on basis of phylogenetic analysis. Five paralogs in pineapple for genes were identified with Ka/Ks ratio varied from 0.20 for and to 0.36 for and , respectively. 16 genes were located on 12 chromosomes out of 25 pineapple chromosomes with highly conserved protein sequence structures. The isoionic points of SBP ranged from 6.05 to 9.57, while molecular weight varied from 22.7 to 121.9 kD. Expression profiles of genes revealed that and (leaf), , , , , , and (sepal), , , and (stamen), , , and (fruit) while the rest of genes showed low expression in studied tissues. Four genes, that is, , , , and , were highly expressed at 4°C, while were upregulated at 45°C. RNA-Seq was validated through qRT-PCR for some genes. Salt stress-induced expression of two genes, that is, and , while in drought stress, and were highly expressed. Our study lays a foundation for further gene function and expression studies of genes in pineapple.