AUTHOR=Cheng Hao , Xie Xiulan , Ren Maozhi , Yang Shuhua , Zhao Xin , Mahna Nasser , Liu Yi , Xu Yufeng , Xiang Yukai , Chai Hua , Zheng Liang , Ge Hong , Jia Ruidong 

TITLE=Characterization of Three SEPALLATA-Like MADS-Box Genes Associated With Floral Development in Paphiopedilum henryanum (Orchidaceae)

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.916081

DOI=10.3389/fpls.2022.916081

ISSN=1664-462X

ABSTRACT=<p><italic>Paphiopedilum</italic> (Orchidaceae) is one of the world’s most popular orchids that is found in tropical and subtropical forests and has an enormous ornamental value. <italic>SEPALLATA-</italic>like (<italic>SEP-</italic>like) MADS-box genes are responsible for floral organ specification. In this study, three <italic>SEP-</italic>like MADS-box genes, <italic>PhSEP1</italic>, <italic>PhSEP2</italic>, and <italic>PhSEP3</italic>, were identified in <italic>Paphiopedilum henryanum</italic>. These genes were 732–916 bp, with conserved SEPI and SEPII motifs. Phylogenetic analysis revealed that <italic>PhSEP</italic> genes were evolutionarily closer to the core eudicot <italic>SEP3</italic> lineage, whereas none of them belonged to core eudicot <italic>SEP1/2/4</italic> clades. <italic>PhSEP</italic> genes displayed non-ubiquitous expression, which was detectable across all floral organs at all developmental stages of the flower buds. Furthermore, subcellular localization experiments revealed the localization of PhSEP proteins in the nucleus. Yeast two-hybrid assays revealed no self-activation of PhSEPs. The protein–protein interactions revealed that PhSEPs possibly interact with B-class DEFICIENS-like and E-class MADS-box proteins. Our study suggests that the three <italic>SEP-</italic>like genes may play key roles in flower development in <italic>P. henryanum</italic>, which will improve our understanding of the roles of the <italic>SEP-</italic>like MADS-box gene family and provide crucial insights into the mechanisms underlying floral development in orchids.</p>