Role of MADS-box Gene in the Development of Flower Organs in Pineapple of a Typical Collective Fruit

Abstract Background: MADS-box genes play crucial roles in plant vegetative and reproductive growth, especially in inflorescences, flower, and fruit. Pineapple is a typical collective fruit, and a comprehensive analysis of the MADS-box gene family in the development of floral organs of pineapple is still lacking. Results: In this study, the whole-genome survey and expression profiling of the MADS-box family in pineapple were introduced. Forty-four AcMADS genes were identified in pineapple, 39 of them were located on 18 chromosomes and five genes were distributed in five scaffolds. Twenty-two AcMADS genes were defined as 15 pairs of segmental duplication events. Syntenic analysis showed that pineapple is closely related to monocotyledon plants. Most members of the type II subfamily of AcMADS genes had higher expression levels in floral organs compared with type I subfamily, thereby suggesting that AcMADS of type II may play more crucial roles in the development of floral organs of pineapple. Six AcMADS genes have significant tissue-specificity expression, thereby suggesting that they may participate in the formation of one or more floral organs. Conclusions: Our findings not only benefit to reveal the functional characterization of MADS-box genes in the floral organ development of pineapple but also provide additional information for further understanding the formation and development collective fruit.