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.

Jing Yang,Zhonglong Guo,Wentao Wang,Xiaoyan Cao,Xiaozeng Yang

doi:10.3390/genes12101588

Abstract

SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors play critical roles in regulating diverse aspects of plant growth and development, including vegetative phase change, plant architecture, anthocyanin accumulation, lateral root growth, etc. In the present study, 15 SPL genes were identified based on the genome data of Codonopsis pilosula, a well-known medicinal plant. Phylogenetic analysis clustered CpSPLs into eight groups (G1-G8) along with SPLs from Arabidopsis thaliana, Solanum lycopersicum, Oryza sativa and Physcomitrella patens. CpSPLs in the same group share similar gene structure and conserved motif composition. Cis-acting elements responding to light, stress and phytohormone widely exist in their promoter regions. Our qRT-PCR results indicated that 15 CpSPLs were differentially expressed in different tissues (root, stem, leaf, flower and calyx), different developmental periods (1, 2 and 3 months after germination) and various conditions (NaCl, MeJA and ABA treatment). Compared with the control, overexpression of CpSPL2 or CpSPL10 significantly promoted not only the growth of hairy roots, but also the accumulation of total saponins and lobetyolin. Our results established a foundation for further investigation of CpSPLs and provided novel insights into their biological functions. As far as we know, this is the first experimental research on gene function in C. pilosula.

Highlights

Transcription factors (TFs) function in various physiological and developmental processes via activating and/or repressing transcription of multiple target genes [1]
As far as we know, this is the first experimental research on gene function in this species. These findings demonstrate that CpSPL2 and CpSPL10 positively regulate the growth of hairy roots and accumulation of active ingredients, which have great potential in improving the yield and quality of Dangshen
A total of 15 SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) containing complete SBP domain were identified based on the genome sequence of C. pilosula and their cDNA sequences were listed in Supplementary Material Table S2

Summary

Introduction

Transcription factors (TFs) function in various physiological and developmental processes via activating and/or repressing transcription of multiple target genes [1]. They have been usually divided into different families according to the sequence of DNA-binding domains and other conserved motifs [2]. SQUAMOSA-promoter binding protein-like (SPL or SBP) TFs are exclusive to plant and characterized by a highly conserved SBP domain and a nuclear localization signal (NLS) at the C-terminus. AmSBP1 and AmSBP2 from Antirrhinum majus were the first discovered SBP-domain proteins in plants and were found to bind to the floral meristem identity gene SQUAMOSA promoter, so named them [3]. With the rapid implication of high-throughput sequencing technology, more and more plant genome data have been released and genome-wide identification of the SPL gene family from model and non-model plants has been identified in Arabidopsis thaliana [8], Oryza sativa [9], Glycine max [10], Solanum lycopersicum [11], Malus domestica [12], Salvia miltiorrhiza [13], Vitis vinifera [14], Phyllostachys edulis [15], Capsicum annuum [16], Ricinus communis [17], etc

Methods

Results

Conclusion