Molecular Cloning, Characterization, and Expression of MiSOC1: A Homolog of the Flowering Gene SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 from Mango (Mangifera indica L).

Junya Wei,Yeyuan Chen,Debing Liu,Jie Tang,Guoyin Liu

doi:10.3389/fpls.2016.01758

Abstract

MADS-box transcription factor plays a crucial role in plant development, especially controlling the formation and development of floral organs. Mango (Mangifera indica L) is an economically important fruit crop, but its molecular control of flowering is largely unknown. To better understand the molecular basis of flowering regulation in mango, we isolated and characterized the MiSOC1, a putative mango orthologs for the Arabidopsis SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1/AGAMOUS-LIKE 20 (SOC1/AGL20) with homology-based cloning and RACE. The full-length cDNA (GenBank accession No.: KP404094) is 945 bp in length including a 74 bp long 5′ UTR and a 189 bp long 3′ UTR and the open reading frame was 733 bps, encoding 223 amino acids with molecular weight 25.6 kD. Both sequence alignment and phylogenetic analysis all indicated that deduced protein contained a conservative MADS-box and semi-conservative K domain and belonged to the SOC1/TM3 subfamily of the MADS-box family. Quantitative real-time PCR was performed to investigate the expression profiles of MiSOC1 gene in different tissues/organs including root, stem, leaves, flower bud, and flower. The result indicated MiSOC1 was widely expressed at different levels in both vegetative and reproductive tissues/organs with the highest expression level in the stems’ leaves and inflorescences, low expression in roots and flowers. The expression of MiSOC1 in different flower developmental stages was different while same tissue –specific pattern among different varieties. In addition, MiSOC1 gene expression was affect by ethephon while high concentration ethephon inhibit the expression of MiSOC1. Overexpression of MiSOC1 resulted in early flowering in Arabidopsis. In conclusion, these results suggest that MiSOC1 may act as induce flower function in mango.

Highlights

Flowering is an important agronomic trait in crops and is the most dramatic transition known as the floral transition changed from vegetative phase to reproductive phase in a life cycle of flowering plant
An EST which showed high sequence similarity compared with SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) gene through BLAST search method in NCBI database search was gained with degenerate primer reverse transcription- polymerase chain reaction (RT-PCR) in our laboratory
SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 act as a main integrator, the structure and function of SOC1 is highly conserved in almost all plant species

Summary

Introduction

Flowering is an important agronomic trait in crops and is the most dramatic transition known as the floral transition changed from vegetative phase to reproductive phase in a life cycle of flowering plant. For achieve reproductive success, determining the optimal flower timing is critical for flowering plants. The regulatory networks integrate different signals to determine whether promote flower transition or repress flower transition which use this way to determine the progression of flowering. Extensive genetic and physiological analyses have revealed that at least four major genetic pathways (long-day, autonomous, vernalization, and gibberellin-dependent pathways) regulated floral induction of A. thaliana (Liu et al, 2012). Several flowering pathway integrators such as FT, SOC1/AGL20, LLFY, and FLC, these gene integrate multiple flowering pathways signals and these genes expression levels eventually determine the exact flowering time (Sung et al, 2003)

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Discussion

Conclusion