Genome-Wide Identification and Salt Stress Response Analysis of the MADS-box Transcription Factors in Sugar Beet

The abiotic stress response and plant development are significantly influenced by MADS-box transcription factors. Nonetheless, the functions of the MADS-box genes in sugar beet stress response are very limited. Here, the sugar beet MADS-box transcription factor gene family was analyzed in sugar beet. The entire genome survey yielded 48 MADS-box genes, which were categorized as type I (Mα, Mβ, and Mγ) and type II (MIKC*, Bs, B, AGL15/AGL18, SVP, FLC, ANR1, SOC1, C/D, Bs, AGL13, E, and A). Five pairs of BvMADS-box genes were fragment duplicated, according to a collinear analysis. A total of fifteen conserved motifs were found, with 1-6 motifs found in each BvMADS-box. Most BvMADS-box genes were expressed more when exposed to salt stress. Among them, the salt-responsive gene BvMADS-box38 is located in the nucleus, as indicated by subcellular localization analysis. Protein interaction network analysis indicated that BvMADS-box proteins were mainly involved in the regulation of the plant flowering process, ABA signal transduction, and stress response. The results of BvMADS-box genes will springboard further studies of their detailed biological functions and inform molecular breeding efforts toward improving sugar beet quality, yield and stress tolerance.