AUTHOR=Dai Jianhua , Wang Minyan , Yin Hengfu , Han Xiaojiao , Fan Yanru , Wei Yi , Lin Jie , Liu Jun 

TITLE=Integrating GC-MS and comparative transcriptome analysis reveals that TsERF66 promotes the biosynthesis of caryophyllene in Toona sinensis tender leaves

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1378418

DOI=10.3389/fpls.2024.1378418

ISSN=1664-462X

ABSTRACT=<sec><title>Introduction</title><p>The strong aromatic characteristics of the tender leaves of <italic>Toona sinensis</italic> determine their quality and economic value.</p></sec><sec><title>Methods and results</title><p>Here, GC-MS analysis revealed that caryophyllene is a key volatile compound in the tender leaves of two different <italic>T. sinensis</italic> varieties, however, the transcriptional mechanisms controlling its gene expression are unknown. Comparative transcriptome analysis revealed significant enrichment of terpenoid synthesis pathway genes, suggesting that the regulation of terpenoid synthesis-related gene expression is an important factor leading to differences in aroma between the two varieties. Further analysis of expression levels and genetic evolution revealed that <italic>TsTPS18</italic> is a caryophyllene synthase, which was confirmed by transient overexpression in <italic>T. sinensis</italic> and <italic>Nicotiana benthamiana</italic> leaves. Furthermore, we screened an AP2/ERF transcriptional factor ERF-IX member, <italic>TsERF66</italic>, for the potential regulation of caryophyllene synthesis. The <italic>TsERF66</italic> had a similar expression trend to that of <italic>TsTPS18</italic> and was highly expressed in high-aroma varieties and tender leaves. Exogenous spraying of MeJA also induced the expression of <italic>TsERF66</italic> and <italic>TsTPS18</italic> and promoted the biosynthesis of caryophyllene. Transient overexpression of <italic>TsERF66</italic> in T. sinensis significantly promoted <italic>TsTPS18</italic> expression and caryophyllene biosynthesis.</p></sec><sec><title>Discussion</title><p>Our results showed that <italic>TsERF66</italic> promoted the expression of <italic>TsTPS18</italic> and the biosynthesis of caryophyllene in <italic>T. sinensis</italic> leaves, providing a strategy for improving the aroma of tender leaves.</p></sec>