Genome-Wide Identification of BAHD Superfamily and Functional Characterization of Bornyl Acetyltransferases Involved in the Bornyl Acetate Biosynthesis in Wurfbainia villosa

Abstract

Bornyl acetate (BA) is known as a natural aromatic monoterpene ester with a wide range of pharmacological and biological activities. Borneol acetyltransferase (BAT), catalyzing borneol and acetyl-CoA to synthesize BA, is alcohol acetyltransferase, which belongs to the BAHD super acyltransferase family, however, BAT, responsible for the biosynthesis of BA, has not yet been characterized. The seeds of Wurfbainia villosa (homotypic synonym: Amomum villosum) are rich in BA. Here we identified 64 members of the BAHD gene family from the genome of W. villosa using both PF02458 (transferase) and PF07247 (AATase) as Hidden Markov Model (HMM) to screen the BAHD genes. A total of sixty-four WvBAHDs are distributed on 14 chromosomes and nine unanchored contigs, clustering into six clades; three WvBAHDs with PF07247 have formed a separated and novel clade: clade VI. Twelve candidate genes belonging to clade I-a, I-b, and VI were selected to clone and characterize in vitro, among which eight genes have been identified to encode BATs acetylating at least one type of borneol to synthesize BA. All eight WvBATs can utilize (−)-borneol as substrates, but only five WvBATs can catalyze (+)-borneol, which is the endogenous borneol substrate in the seeds of W. villosa; WvBAT3 and WvBAT4 present the better catalytic efficiency on (+)-borneol than the others. The temporal and spatial expression patterns of WvBATs indicate that WvBAT3 and WvBAT4 are seed-specific expression genes, and their expression levels are correlated with the accumulation of BA, suggesting WvBAT3 and WvBAT4 might be the two key BATs for BA synthesis in the seeds of W. villosa. This is the first report on BAT responsible for the last biosynthetic step of BA, which will contribute to further studies on BA biosynthesis and metabolism engineering of BA in other plants or heterologous hosts.

Multi-omics Comparison among Populations of Three Plant Sources of Amomi Fructus

“…The copyright holder for this this version posted January 29, 2023. ; https://doi.org/10.1101/2023.01. 27.525993 doi: bioRxiv preprint of each origin varies [6][7][8][9] , although they are used as the same TCM clinically. For example, Ephedrae herba is the dry herbaceous stem of Ephedra sinica, E. intermedia or E. equisetina 10 .…”

“…The copyright holder for this this version posted January 29, 2023. ; https://doi.org/10.1101/2023.01. 27.525993 doi: bioRxiv preprint Profound difference has been observed in the abundance of volatile metabolites of the three plant (sub)species of AF [20][21][22] , which is reflected in the different standards for the abundance of volatile oil of the three source (sub)species in Chinese Pharmacopoeia.…”

“…Genetic studies have been advanced by a recent release of the genome of WVV 27 , and a large number of terpene synthesis (TPS) genes have been screened and verified, preprint (which was not certified by peer review) is the author/funder. All rights reserved.…”

“…The copyright holder for this this version posted January 29, 2023. ; https://doi.org/10.1101/2023.01.27.525993 doi: bioRxiv preprint revealing parts of biosynthetic pathway of terpenes in WVV [27][28][29][30][31][32] . The identified genes included linalool synthase gene (AvTPS2), α-santalene and α-bergimonene synthase gene (AvTPS15) 33 , α-pinene and β-pinene synthase gene (AvPS) 34 .…”

“…Genetic studies have been advanced by a recent release of the genome of WVV 27 , and a large number of terpene synthesis (TPS) genes have been screened and verified, revealing parts of biosynthetic pathway of terpenes in WVV [27][28][29][30][31][32] . The identified genes included linalool synthase gene (AvTPS2), α-santalene and α-bergimonene synthase gene (AvTPS15) 33 , α-pinene and β-pinene synthase gene (AvPS) 34 .…”