De Novo Assembly and Characterization of the Transcriptome of the Chinese Medicinal Herb, Gentiana rigescens

et al. 2020

Preprint

BackgroundMembers of the cytochrome P450 (CYP450) gene superfamily have been shown to play essential roles in regulating secondary metabolites biosynthesis. However, the systematic identification and bioinformatics analysis of CYP450s have not been reported in Aralia elata (Miq.) Seem, a highly valued medicinal plant. ResultsIn the present study we conducted the RNA-sequencing (RNA-seq) analysis of the leaves, stems, and roots of A. elata, yielding 66,713 total unigenes. Following the annotation and classification of these unigenes, we were able to identify two pathways and 19 putative genes associated with the synthesis of triterpenoid saponins in these plants, with qRT-PCR subsequently being used to validate these gene expression patterns. Scanning with the CYP450 model from Pfam resulted in the identification of 111 full-length and 143 partial-length CYP450s, with the full-length CYP450s being further clustered into 7 clans and 36 families. Through phylogenetic and conserved motif analyses, we were further able to group these CYP450 proteins into two primary branches: A-type (53%) and non-A type (47%). We further conducted representative protein sequence alignment for these CYP450 family members, with secondary elements being assigned in light of the recently published Arabidopsis CYP90B1 structure. Using the available sequence information, we further identified predicted substrate recognition sites (SRSs) and substrate binding sites within these putative proteins.We further assessed the expression patterns of these 111 CYP450 genes across A. elata tissues, with 12 members of this gene family being selected at random for qRT-PCR validation. From these data, we identified CYP716A295 and CYP716A296 as the candidate genes most likely to be associated with oleanolic acid synthesis, while CYP72A763 was identified as being the most likely to play a role in hederagenin biosynthesis. Finally, we assessed the subcellular localization of these CYP450 proteins within Arabidopsis protoplasts, highlighting the fact that they localize to the endoplasmic reticulum.ConclusionsThis study presents a systematic analysis of the CYP450 gene family in A. elata and provided a foundation for further functional characterization of CYP450 genes.

Section: Discussionsupporting

confidence: 79%

Identification and analysis of CYP450 supergene family members from the transcriptome of Aralia elata (Miq.) Seem reveal candidate genes for triterpenoid saponins biosynthesis

et al. 2020

Preprint

“…An Illumina HiSeq 4000 platform was used to sequence the libraries prepared from these 9 samples, yielding 66,713 unigenes, of which over half were well-annotated within public databases. The N50 length and average length of the unigenes were consistent with the effective and high-quality assembly of these sequencing results [35]. The results of this deep sequencing analysis have immense value as a means of identifying those genes involved in the biosynthesis of pharmacologically-relevant secondary metabolites in A. elata, as evidenced by our identification of CYP450s and UGTs involved in triterpenoid saponins in these plants.…”

Section: Discussionsupporting

confidence: 79%

Identification and analysis of CYP450 and UGT supergene family members from the transcriptome of Aralia elata (Miq.) Seem reveal candidate genes for triterpenoid saponin biosynthesis

et al. 2020

Preprint

Background: Members of the cytochrome P450 (CYP450) and UDP-glycosyltransferases (UGT) gene superfamily have been shown to play essential roles in regulating secondary metabolites biosynthesis. However, the systematic identification of CYP450s and UGTs have not been reported in Aralia elata (Miq.) Seem , a highly valued medicinal plant. Results: In the present study we conducted the RNA-sequencing (RNA-seq) analysis of the leaves, stems, and roots of A. elata, yielding 66,713 total unigenes. Following the annotation and KEGG pathway analysis, we were able to identify 64 unigenes related to triterpenoid skeleton biosynthesis, 254 CYP450s and 122 UGTs, respectively. 150 CYP450s and 92 UGTs encoding >300 amino acid proteins were utilized for phylogenetic and tissue-specific expression analyses. This allowed us to cluster 150 CYP450s into 9 clans and 40 families, and then these CYP450 proteins were further grouped into two primary branches: A-type (53%) and non-A type (47%). A phylogenetic analysis of 92 UGTs and other plant UGTs led to clustering into 16 groups (A-P). We further assessed the expression patterns of these CYP450 and UGT genes across A. elata tissues, with 23 CYP450 and 16 UGT members being selected for qRT-PCR validation, respectively. From these data, we identified CYP716A295 and CYP716A296 as the candidate genes most likely to be associated with oleanolic acid synthesis, while CYP72A763 and CYP72A776 was identified as being the most likely to play a role in hederagenin biosynthesis. We also selected five unigenes as the best candidates for oleanolic acid 3-O-glucosyltransferase. Finally, we assessed the subcellular localization of three CYP450 proteins within Arabidopsis protoplasts, highlighting the fact that they localize to the endoplasmic reticulum. Conclusions: This study presents a systematic analysis of the CYP450 and UGT gene family in A. elata and provided a foundation for further functional characterization of these two multigene family.

“…An Illumina HiSeq 4000 platform was used to sequence the libraries prepared from these 9 samples, yielding 66,713 unigenes, of which over half were well-annotated within public databases. The N50 and average lengths of the unigenes were consistent with the effective and high-quality assembly of these sequencing results [35]. The results of this deep sequencing analysis have immense value as a means of identifying those genes involved in the biosynthesis of pharmacologically relevant secondary metabolites in A. elata, as evidenced by our identification of CYP450s and UGTs involved in triterpenoid saponins in these plants.…”

Section: Discussionsupporting

confidence: 78%

Identification and analysis of CYP450 and UGT supergene family members from the transcriptome of Aralia elata (Miq.) Seem reveal candidate genes for triterpenoid saponin biosynthesis

et al. 2020

Preprint

Background: Members of the cytochrome P450 (CYP450) and UDP-glycosyltransferase (UGT) gene superfamily have been shown to play essential roles in regulating secondary metabolite biosynthesis. However, the systematic identification of CYP450s and UGTs has not been reported in Aralia elata (Miq.) Seem, a highly valued medicinal plant. Results: In the present study, we conducted the RNA-sequencing (RNA-seq) analysis of the leaves, stems, and roots of A. elata, yielding 66,713 total unigenes. Following annotation and KEGG pathway analysis, we were able to identify 64 unigenes related to triterpenoid skeleton biosynthesis, 254 CYP450s and 122 UGTs, respectively. A total of 150 CYP450s and 92 UGTs encoding >300 amino acid proteins were utilized for phylogenetic and tissue-specific expression analyses. This allowed us to cluster 150 CYP450s into 9 clans and 40 families, and then these CYP450 proteins were further grouped into two primary branches: A-type (53%) and non-A-type (47%). A phylogenetic analysis of 92 UGTs and other plant UGTs led to clustering into 16 groups (A-P). We further assessed the expression patterns of these CYP450 and UGT genes across A. elata tissues, with 23 CYP450 and 16 UGT members being selected for qRT-PCR validation, respectively. From these data, we identified CYP716A295 and CYP716A296 as the candidate genes most likely to be associated with oleanolic acid synthesis, while CYP72A763 and CYP72A776 were identified as being the most likely to play roles in hederagenin biosynthesis. We also selected five unigenes as the best candidates for oleanolic acid 3-O-glucosyltransferase. Finally, we assessed the subcellular localization of three CYP450 proteins within Arabidopsis protoplasts, highlighting the fact that they localize to the endoplasmic reticulum.Conclusions: This study presents a systematic analysis of the CYP450 and UGT gene family in A. elata and provides a foundation for further functional characterization of these two multigene families.