Genome-Wide Identification and Characterization of SQUAMOSA—Promoter-Binding Protein (SBP) Genes Involved in the Flowering Development of Citrus Clementina

Abstract

SQUAMOSA-promoter binding protein (SBP)-box genes encode a family of plant-specific transcription factors that play vital roles in plant growth and development. In this study, 15 SBP-box genes were identified and isolated from Citrus clementina (CclSBPs), where 10 of these genes were predicted to be putative targets of Citrus clementina microRNA156 (CclmiR156). The 15 CclSBP genes could be classified into six groups based on phylogenetic analysis, diverse intron–exon structure, and motif prediction, similar to the SQUAMOSA promoter binding protein-like (SPL) gene family of Populus trichocarpa and Arabidopsis thaliana. Furthermore, CclSBPs classified into a group/subgroup have similar gene structures and conserved motifs, implying their functional redundancy. Tissue-specific expression analysis of CclSBPs demonstrated their diversified expression patterns. To further explore the potential role of CclSBPs during floral inductive water deficits, the dynamic changes of the 15 CclSBPs were investigated during floral inductive water deficits, and the results showed that some CclSBPs were associated with floral induction. Among these genes, CclSBP6 was not homologous to the Arabidopsis SBP-box gene family, and CclSBP7 was regulated by being alternatively spliced. Therefore, CclSBP6 and CclSBP7 were genetically transformed in Arabidopsis. Overexpression of the two genes changed the flowering time of Arabidopsis.

Genome-wide characterization of SPL gene family in Codonopsis pilosula reveals the novel roles of CpSPL2 and CpSPL10 in promoting the accumulation of secondary metabolites and growth of C. pilosula hairy root

“…The results showed that CpSPL1 and CpSPL14 in G1 exhibited similar expression patterns, and the expression patterns of paralogous CpSPL9 and CpSPL15 in G5 showed high similarity. Our results were consistent with previous conclusion that paralogous SPL genes in the same group often showed similar expression pro les [46,47]. AtSPL9, AtSPL10, and AtSPL15 contribute to the vegetative to reproductive phase transition [8].…”

Genome-Wide Characterization of SPL Gene Family in Codonopsis pilosula Reveals the Functions of CpSPL2 and CpSPL10 in Promoting the Accumulation of Secondary Metabolites and Growth of C. pilosula Hairy Root

“…The results showed that CpSPL1 and CpSPL14 in G8 exhibited similar expression patterns, and the expression patterns of paralogous CpSPL9 and CpSPL15 in G6 showed high similarity. Our results were consistent with previous conclusion that paralogous SPL genes in the same group often showed similar expression profiles [45,46]. AtSPL9, AtSPL10 and AtSPL15 contribute to the vegetative to reproductive phase transition [8].…”

Genomic insights into citrus domestication and its important agronomic traits

“…(2005) Nishikawa et al. (2007) 14 CclSBP7 Clementine mandarin Arabidopsis thaliana Zeng et al. (2019) 15 miR3954 Citrus Hong Kong kumquat ( Fortunella hindsii ) Liu et al.…”

“…A total of 16 and 15 SBP-box genes have been identified in Arabidopsis and citrus, respectively. To understand the function of these genes, clementine mandarin SBP-box genes were cloned and overexpressed in Arabidopsis , and transgenic Arabidopsis plants expressing the CclSBP7 gene showed flowered earlier than control plants ( Zeng et al., 2019 ). These results indicate that CclSBP7 from is involved in early flowering in clementine mandarin and can induce early flowering in other citrus species to shorten the juvenile phase.…”