Abstract: In this study, the MADS-box gene family was identified and analyzed at the genomic level of Ipomoea trifida, a close relative of Ipomoea batatas. The results showed that a total of 38 ItfMADS gene members were identified. According to the analysis of physical and chemical properties, the number of amino acids in each member was very different, and 26 members were alkaline. Subcellular localization indicated that 32 of these members were located in the nucleus. According to the phylogenetic analysis, ItfMADS gene family were divided into type Ⅰ and type Ⅱ. Type Ⅰ consisted of 9 members and type Ⅱ had 29 members. Chromosome localization analysis found that the 38 ItfMADS genes were distributed unevenly on 12 chromosomes. There were 9 members on Chromosome11 (Chr11), while there was only one member on Chr12 and Chr00, respectively. Analysis of conserved domain indicated that all the members contained MADS-box domain, and type Ⅱ members also contained K domain; motif 1 and motif 3 were both important conserved motifs in ItfMADS proteins. Analysis of gene structure showed that the number of introns and exons varied greatly among the 38 ItfMADS genes. Promoter analysis found that cis-acting element of light response were of the most amount. Expression pattern analysis revealed that ItfMADS genes expressed differently in different tissues, and their express responses to different stresses were also different. This study provided a foundation for further functional identification of MADS-box gene of Ipomoea batatas.
Key words: Ipomoea trifida; MADS-box; genome-wide analysis; tissue specificity; expression analysis
（Acta Laser Biology Sinica, 2021, 30(3): 223-235）