Deep sequencing and transcriptome analysis to identify genes related to biosynthesis of aristolochic acid in Asarum heterotropoides

Abstract

Asarum spp. are important medicinal plants that have the potential for use in treating various types of fevers. Aristolochic acid is one of the main toxic compounds present in these plants. To improve our understanding of the biosynthetic pathway of aristolochic acid, we sequenced the transcriptome of the root and leaf tissues of Asarum heterotropoides and performed de novo sequence assembly. The data were stitched together to produce 468,357 transcripts with an N50 of 611 bp. The data were annotated with various databases (RefSeq non-redundant proteins [Nr], Swiss-Prot, Kyoto Encyclopaedia of Genes and Genomes [KEGG], Clusters of Orthologous Groups/EuKaryotic Orthologous Groups [COG/KOG], and Gene Ontology [GO]) and were annotated. There were 205,165 transcripts (43.81%) of differentially expressed genes in the roots and leaves, which were shown to be involved in biosynthesis, transport, and catabolism, and 100 genes in defence mechanisms. Three candidate transcripts (TyrDC1, TyrDC2, and TyrDC3) were discovered in these differential genes. TyrDC may be a key enzyme in the biosynthesis pathway of aristolochic acid identified using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and high-performance liquid chromatography (HPLC). The transcriptome data and analysis presented here lay the foundation for further research into these important medicinal plants.

Chromosome-level genome assembly of Aristolochia contorta provides insights into the biosynthesis of benzylisoquinoline alkaloids and aristolochic acids

“…AAs are biogenetically derived from BIA precursors, and magnoflorine is always identified together with AAs in various Aristolochia species [ 11 ]. In addition, norlaudanosoline has been considered to be an intermediate of AA biosynthetic pathways for several decades [ 10 – 14 ]. However, the distribution of norlaudanosoline in plants is narrow: it has only been found in M. cordata [ 15 ].…”

“…Unfortunately, there is little information available on this pathway, which was analyzed only in a few studies in the 1960s [ 10 – 13 ]. In addition, only one gene (TyrDC) that is probably involved upstream of the pathway has been cloned [ 14 ]. In the AA biosynthetic pathway proposed in the 1960s, norlaudanosoline, orientaline, orientalinone, and orientalinol were considered to be intermediates of AA biosynthesis.…”

Transcriptome Analysis of Clinopodium chinense (Benth.) O. Kuntze and Identification of Genes Involved in Triterpenoid Saponin Biosynthesis

“…Among these unigenes, 102,154 (75.13%) were mapped to seven public databases. Compared with other medicinal plant transcriptome databases, the average length and N50 values of unigenes in C. chinense (average length = 1195 bp; N50 = 1890 bp) were longer than those in Artemisia argyi (average length = 926 bp; N50 = 1456 bp) [17], Oroxylum indicum (average length = 1080 bp; N50 = 1783 bp) [21], and Asarum heterotropoides (average length = 611 bp; N50 = 507.36 bp) [22]; these results demonstrated that our transcriptome database was of high quality. In particular, the sequence size distribution was homogeneous and 10,942 (48.61%) unigenes were longer than 1000 bp, indicating successful generation of transcriptional data.…”

Microbial degradation of aristolochic acid I by endophytic fungus A.h-Fs-1 of Asarum heterotropoides

“…AAs exhibit nephrotoxicity, liver toxicity, carcinogenesis, and mutagenesis and are classified as grade I carcinogens (Wang et al, 2018). Further studies indicate that AAs have multiple types of molecular structure, with aristolochic acid I (AAI) being the most toxic (Balachandran et al, 2005; Supplementary Figure S2).…”