AUTHOR=Song Cheng , Li Xiaoli , Jia Bin , Liu Li , Wei Peipei , Manzoor Muhammad Aamir , Wang Fang , Li Biqi Yao , Wang Guanglin , Chen Cunwu , Han Bangxing 

TITLE=Comparative Transcriptomics Unveil the Crucial Genes Involved in Coumarin Biosynthesis in Peucedanum praeruptorum Dunn

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.899819

DOI=10.3389/fpls.2022.899819

ISSN=1664-462X

ABSTRACT=<p><italic>Peucedanum praeruptorum</italic> Dunn is a commonly used traditional Chinese medicine that is abundant in furano- and dihydropyrano coumarins. When <italic>P. praeruptorum</italic> reaches the bolting stage, the roots gradually lignified, and the content of coumarins declines rapidly. Non-bolting has always been a decisive factor for harvesting the <italic>P. praeruptorum</italic> materials. To evaluate the amount of coumarin components in unbolted and bolted <italic>P. praeruptorum</italic>, the variations of praeruptorin A, praeruptorin B, praeruptorin E, peucedanocoumarin I, and peucedanocoumarin II were determined. Additionally, 336,505 transcripts were obtained from the comparative transcriptome data. Among them, a total of 1,573 differentially expressed genes were screened out. To identify the critical genes involved in coumarin biosynthesis, comparative transcriptomics coupled with co-expression associated analysis was conducted. Finally, coumarin biosynthesis-related eighteen candidate genes were selected for the validation of <italic>q</italic>PCR. Additionally, a phylogenetic tree and the expression profile of ATP-binding cassette (ABC) transporters were constructed. To clarify the main genes in the regulation of coumarin biosynthesis, the interaction network of the co-expression genes from thirteen modules was constructed. Current results exhibited the significant increment of praeruptorin A, praeruptorin B and praeruptorin E in the bolted <italic>P. praeruptorum</italic>. Although, peucedanocoumarin I and peucedanocoumarin II were slightly increased. Besides the content of coumarins, the essential genes involved in the coumarin biosynthesis also exhibited an overall downward trend after bolting. Three <italic>peroxidases</italic> (<italic>PRXs</italic>) involved in the production of lignin monomers had been demonstrated to be downregulated. <italic>PAL</italic>, <italic>C4H</italic>, <italic>HCT</italic>, <italic>COMT</italic>, <italic>CCoAOMT</italic>, and some ABC transporters were dramatically downregulated at the bolting stage. These results indicated that the downregulation of coumarin biosynthetic genes in the bolted <italic>P. praeruptorum</italic> ultimately reduced the formation of coumarins. However, the mechanism through which bolting indirectly affects the formation of coumarin still needs extra functional verification.</p>