AUTHOR=Zhang Hao , Ding Xupo , Wang Hao , Chen Huiqin , Dong Wenhua , Zhu Jiahong , Wang Jian , Peng Shiqing , Dai Haofu , Mei Wenli 

TITLE=Systematic evolution of bZIP transcription factors in Malvales and functional exploration of AsbZIP14 and AsbZIP41 in Aquilaria sinensis

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1243323

DOI=10.3389/fpls.2023.1243323

ISSN=1664-462X

ABSTRACT=<sec><title>Introduction</title><p>Agarwood, the dark-brown resin produced by <italic>Aquilaria</italic> trees, has been widely used as incense, spice, perfume or traditional medicine and 2-(2-phenethyl) chromones (PECs) are the key markers responsible for agarwood formation. But the biosynthesis and regulatory mechanism of PECs were still not illuminated. The transcription factor of basic leucine zipper (bZIP) presented the pivotal regulatory roles in various secondary metabolites biosynthesis in plants, which might also contribute to regulate PECs biosynthesis. However, molecular evolution and function of bZIP are rarely reported in Malvales plants, especially in <italic>Aquilaria</italic> trees.</p></sec><sec><title>Methods and results</title><p>Here, 1,150 <italic>bZIPs</italic> were comprehensively identified from twelve Malvales and model species genomes and the evolutionary process were subsequently analyzed. Duplication types and collinearity indicated that <italic>bZIP</italic> is an ancient or conserved TF family and recent whole genome duplication drove its evolution. Interesting is that fewer <italic>bZIPs</italic> in <italic>A. sinensis</italic> than that species also experienced two genome duplication events in Malvales. 62 AsbZIPs were divided into 13 subfamilies and gene structures, conservative domains, motifs, <italic>cis</italic>-elements, and nearby genes of <italic>AsbZIPs</italic> were further characterized. Seven <italic>AsbZIPs</italic> in subfamily D were significantly regulated by ethylene and agarwood inducer. As the typical representation of subfamily D, <italic>AsbZIP14</italic> and <italic>AsbZIP41</italic> were localized in nuclear and potentially regulated PECs biosynthesis by activating or suppressing type III polyketide synthases (PKSs) genes expression via interaction with the <italic>AsPKS</italic> promoters.</p></sec><sec><title>Discussion</title><p>Our results provide a basis for molecular evolution of <italic>bZIP</italic> gene family in Malvales and facilitate the understanding the potential functions of <italic>AsbZIP</italic> in regulating 2-(2-phenethyl) chromone biosynthesis and agarwood formation.</p></sec>