Genome-Wide Investigation of MADS-Box Genes in Flower Development and Environmental Acclimation of Lumnitzera littorea (Jack) Voigt

<i>Lumnitzera littorea</i> (Jack) Voigt is an endangered mangrove species in China. Low fecundity and environmental pressure are supposed to be key factors limiting the population expansion of <i>L. littorea</i>. Transcription factors with the MADS-box domain are crucial regulators of plant flower development, reproduction, and stress response. In this study, we performed a comprehensive investigation into the features and functions of <i>MADS-box</i> genes of <i>L. littorea</i>. Sixty-three <i>LlMADS</i> genes with similar structure and motif composition were identified in the <i>L. littorea</i> genome, and these genes were unevenly distributed on the 11 chromosomes. Segmental duplication was suggested to make a main contribution to the expansion of the <i>LlMADS</i> gene family. Some <i>LIMADS</i> genes exhibited differential expression in different flower types or in response to cold stress. Overexpression of the B-class gene <i>LlMADS37</i> had substantial effects on the flower morphology and flowering time of transgenic <i>Arabidopsis</i> plants, demonstrating its key role in regulating flower morphogenesis and inflorescence. These findings largely enrich our understanding of the functional importance of <i>MADS-box</i> genes in the inflorescence and stress acclimation of <i>L. littorea</i> and provide valuable resources for future genetic research to improve the conservation of this species.