AUTHOR=Wang Baiyu , Hu Wenshun , Fang Yaxue , Feng Xiaoxi , Fang Jingping , Zou Tengyue , Zheng Shaoquan , Ming Ray , Zhang Jisen 

TITLE=Comparative Analysis of the MADS-Box Genes Revealed Their Potential Functions for Flower and Fruit Development in Longan (Dimocarpus longan)

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.813798

DOI=10.3389/fpls.2021.813798

ISSN=1664-462X

ABSTRACT=<p>Longan (<italic>Dimocarpus longan</italic> Lour.) is an important economic crop widely planted in tropical and subtropical regions, and flower and fruit development play decisive effects on the longan yield and fruit quality formation. MCM1, AGAMOUS, DEFICIENS, Serum Response Factor (MADS)-box transcription factor family plays important roles for the flowering time, floral organ identity, and fruit development in plants. However, there is no systematic information of MADS-box family in longan. In this study, 114 MADS-box genes were identified from the longan genome, phylogenetic analysis divided them into type I (<italic>M</italic>α, <italic>M</italic>β, <italic>M</italic>γ) and type II (<italic>MIKC</italic>*, <italic>MIKC</italic><italic><sup>C</sup></italic>) groups, and <italic>MIKC</italic><italic><sup>C</sup></italic> genes were further clustered into 12 subfamilies. Comparative genomic analysis of 12 representative plant species revealed the conservation of type II in Sapindaceae and analysis of cis-elements revealed that <italic>Dof</italic> transcription factors might directly regulate the <italic>MIKC</italic><italic><sup>C</sup></italic> genes. An ABCDE model was proposed for longan based on the phylogenetic analysis and expression patterns of MADS-box genes. Transcriptome analysis revealed that <italic>MIKC</italic><italic><sup>C</sup></italic> genes showed wide expression spectrums, particularly in reproductive organs. From 35 days after KClO<sub>3</sub> treatment, 11 <italic>MIKC</italic> genes were up-regulated, suggesting a crucial role in off-season flower induction, while <italic>DlFLC</italic>, <italic>DlSOC1</italic>, <italic>DlSVP</italic>, and <italic>DlSVP-LIKE</italic> may act as the inhibitors. The gene expression patterns of longan fruit development indicated that <italic>DlSTK</italic>, <italic>DlSEP1/2</italic>, and <italic>DlMADS53</italic> could be involved in fruit growth and ripening. This paper carried out the whole genome identification and analysis of the longan MADS-box family for the first time, which provides new insights for further understanding its function in flowers and fruit.</p>