High-quality genome assembly of Impatiens noli-tangere reveals key insights into α-linolenic acid biosynthesis and metabolic volatiles

Abstract

Impatiens noli-tangere accumulates abundant α-linolenic acid (ALA) and its metabolic volatiles, which hold significant potential for applications in healthcare and agriculture. However, the genetic basis underlying their biosynthesis has not been systematically investigated. Here, we present a high-quality genome assembly for I. noli-tangere (614.46 Mb). Despite a high repetitive sequence content (70.46%), it avoided excessive expansion due to the efficient elimination of long terminal repeat retrotransposons. Phylogenomic analyses revealed that I. noli-tangere experienced two whole-genome duplication (WGD) events, with WGD-derived genes predominating in oil biosynthesis. Notably, IntFAD3, a WGD-duplicated fatty acid desaturase, was identified as a key seed-specific gene for ALA biosynthesis. Its regulation by the transcription factor IntbZIP38 was functionally validated through yeast one-hybrid, luciferase, β-glucuronidase, and transgenic functional assays. Furthermore, (E)-2-hexenal, the predominant ALA-derived volatile in leaves, exhibited potent antifungal activity against Botrytis cinerea (minimum inhibitory concentration: 0.188 ml/l), with its biosynthesis linked to Int13-HPL. These findings provide genomic and functional insights into ALA biosynthesis and metabolic volatiles in I. noli-tangere, supporting its potential in sustainable agriculture and bioactive compound development.

Acknowledgements

This work is dedicated to the memory of Yushan Zhou, the father of Yunwei Zhou. His passion for plants and interest in the antifungal properties of Impatiens inspired the initiation of this study. This research was supported by the National Science and Technology Basic Project of China (2021FY100702). Genome sequencing, Hi-C sequencing, and assembly services were provided by Novogene Co., Ltd. We are grateful to the Darwin Tree of Life Project for providing the genome assembly data of I. glandulifera (PRJEB44449). We thank Professor Ben Watson (Northeast Forestry University) for his professional editing of the English language in this manuscript.

Author contributions

Y.Z. and H.G. conceived and initiated the project. N.X., Y.D., B.X., and S.S. collected the samples. Y.Z., H.G., N.X., and M.H. designed the experiments. N.X., F.K., S.C., and Y.Z. conducted the experiments, while N.X., F.K., and Y.Y. performed the data analysis. N.X. and Y.D. prepared the initial article draft, with revisions contributed by Y.Y., M.H., H.G., and Y.Z. All authors reviewed and approved the final version of the manuscript.

Data availability

The genome assembly has been deposited in the China National GeneBank DataBase (CNGBdb, https://db.cngb.org/), under accession number CNP0005329. Transcriptomic sequencing data are available at the NCBI database (https://www.ncbi.nlm.nih.gov/) under accession number PRJNA1131936 and PRJNA1257970. The GenBank accession numbers for the nucleotide sequences utilized in this study are as follows: IntFAD3 (PQ570564), IntFAD7 (PQ570566), IntbZIP38 (PQ570565), Int13-HPL (PQ570563).

Conflict of interest statement

The authors declare no competing interests.

Supplementary data

Supplementary data is available at Horticulture Research online.

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