Genome-wide identification and expression pattern analysis of the MADS-box gene family in Vaccinium bracteatum

Background Vaccinium bracteatum Thunb . is a plant with notable medicinal and economic value and is widely distributed throughout China. The MADS-box gene family is a transcription factor family found across eukaryotes that is involved in many biological processes, including flower development and fruit ripening. However, systematic information on MADS-box genes in V. bracteatum is lacking. Results This study presents the first comprehensive genome-wide identification and functional characterization of the MADS-box transcription factor family in Vaccinium bracteatum . Through bioinformatic analyses, a total of 74 VaMADS genes were identified and classified into two major groups: Type I (44 genes) and Type II (30 genes). The 24 VaMADS genes were defined as 17 pairs of duplication events, including 11 pairs of segmental duplications and 6 pairs of tandem duplications. The collinearity analysis indicated that tandem and segmental duplication contributed to the expansion of MADS-box genes. Gene structure analysis revealed that Type I genes typically have a simple architecture with one exon and no introns, whereas Type II genes have more complex structures with multiple exons and introns, showing high conservation within the subfamilies. Cis-acting element analysis revealed that VaMADS genes participate in growth, development, and stress resistance. Type II genes had higher expression levels than Type I genes during fruit development, indicating that Type II genes play a crucial role in fruit ripening. Conclusions This study identified the MADS gene family in Vaccinium bracteatum for the first time, providing an important reference for further in-depth studies on the function of the MADS-box genes in plant and fruit development.