Minzhen Yin1,2,3, Shanshan Chu1,4, Tingyu Shan1, Liangping Zha5,6, Huasheng Peng7,8,9. 1. School of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230012, China. 2. State Key Laboratory of Dao-Di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China. 3. Research Unit of DAO-DI Herbs, Chinese Academy of Medical Sciences, 2019RU57, Beijing, 100700, China. 4. Anhui Province Key Laboratory of Research & Development of Chinese Medicine, Hefei, 230012, China. 5. School of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230012, China. zlp_ahtcm@126.com. 6. Institute of Conservation and Development of Traditional Chinese Medicine Resources, Anhui Academy of Chinese Medicine, Hefei, 230012, China. zlp_ahtcm@126.com. 7. School of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230012, China. hspeng@126.com. 8. State Key Laboratory of Dao-Di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China. hspeng@126.com. 9. Research Unit of DAO-DI Herbs, Chinese Academy of Medical Sciences, 2019RU57, Beijing, 100700, China. hspeng@126.com.
Abstract
BACKGROUND: Astragalus mongholicus Bunge is an important medicinal plant used in traditional Chinese medicine. It is rich in isoflavonoids and triterpenoid saponins. Although these active constituents of A. mongholicus have been discovered for a long time, the genetic basis of isoflavonoid and triterpenoid saponin biosynthesis in this plant is virtually unknown because of the lack of a reference genome. Here, we used a combination of next-generation sequencing (NGS) and single-molecule real-time (SMRT) sequencing to identify genes involved in the biosynthetic pathway of secondary metabolites in A. mongholicus. RESULTS: In this study, NGS, SMRT sequencing, and targeted compound analysis were combined to investigate the association between isoflavonoid and triterpenoid saponin content, and specific gene expression in the root, stem, and leaves of A. mongholicus. Overall, 643,812 CCS reads were generated, yielding 121,107 non-redundant transcript isoforms with an N50 value of 2124 bp. Based on these highly accurate transcripts, 104,756 (86.50%) transcripts were successfully annotated by any of the seven databases (NR, NT, Swissprot, KEGG, KOG, Pfam and GO). Levels of four isoflavonoids and four astragalosides (triterpenoid saponins) were determined. Forty-four differentially expressed genes (DEGs) involved in isoflavonoid biosynthesis and 44 DEGs from 16 gene families that encode enzymes involved in triterpenoid saponin biosynthesis were identified. Transcription factors (TFs) associated with isoflavonoid and triterpenoid saponin biosynthesis, including 72 MYBs, 53 bHLHs, 64 AP2-EREBPs, and 11 bZIPs, were also identified. The above transcripts showed different expression trends in different plant organs. CONCLUSIONS: This study provides important genetic information on the A. mongholicus genes that are essential for isoflavonoid and triterpenoid saponin biosynthesis, and provides a basis for developing the medicinal value of this plant.
BACKGROUND: Astragalus mongholicus Bunge is an important medicinal plant used in traditional Chinese medicine. It is rich in isoflavonoids and triterpenoid saponins. Although these active constituents of A. mongholicus have been discovered for a long time, the genetic basis of isoflavonoid and triterpenoid saponin biosynthesis in this plant is virtually unknown because of the lack of a reference genome. Here, we used a combination of next-generation sequencing (NGS) and single-molecule real-time (SMRT) sequencing to identify genes involved in the biosynthetic pathway of secondary metabolites in A. mongholicus. RESULTS: In this study, NGS, SMRT sequencing, and targeted compound analysis were combined to investigate the association between isoflavonoid and triterpenoid saponin content, and specific gene expression in the root, stem, and leaves of A. mongholicus. Overall, 643,812 CCS reads were generated, yielding 121,107 non-redundant transcript isoforms with an N50 value of 2124 bp. Based on these highly accurate transcripts, 104,756 (86.50%) transcripts were successfully annotated by any of the seven databases (NR, NT, Swissprot, KEGG, KOG, Pfam and GO). Levels of four isoflavonoids and four astragalosides (triterpenoid saponins) were determined. Forty-four differentially expressed genes (DEGs) involved in isoflavonoid biosynthesis and 44 DEGs from 16 gene families that encode enzymes involved in triterpenoid saponin biosynthesis were identified. Transcription factors (TFs) associated with isoflavonoid and triterpenoid saponin biosynthesis, including 72 MYBs, 53 bHLHs, 64 AP2-EREBPs, and 11 bZIPs, were also identified. The above transcripts showed different expression trends in different plant organs. CONCLUSIONS: This study provides important genetic information on the A. mongholicus genes that are essential for isoflavonoid and triterpenoid saponin biosynthesis, and provides a basis for developing the medicinal value of this plant.
Authors: Kevin M Davies; Rubina Jibran; Yanfei Zhou; Nick W Albert; David A Brummell; Brian R Jordan; John L Bowman; Kathy E Schwinn Journal: Front Plant Sci Date: 2020-02-04 Impact factor: 5.753