Transcriptome analysis for molecular landscaping of genes controlling diterpene andrographolide biosynthesis in Andrographis paniculata (Burm. f.) Nees

Abstract

Kalmegh [ Andrographis paniculata (Burm. f. ) Nees.] is one of the essential medicinal plants due to an important terpenoid, i.e. andrographolide possesses immense therapeutic and pharmacological uses. The experiment was performed to elucidate the expression of candidate genes associated with andrographolide biosynthesis. Based on results obtained in chromatography for andrographolide content analysis of six genotypes, two contrast genotypes, i.e. IC-520361 (maximum andrographolide content—2.33%) and Anand Local (lowest andrographolide content—1.01%) were selected for the transcriptome analysis. A total of 1.04 Gb of raw data were produced using MiSeq Illumina platform, in which IC 520361 generated 645 million base pairs sequence along with 4,524,251 raw reads and Anand Local produced 419 million base pairs sequence along with 3,021,316 raw reads. The combined assembly of high quality reads generated for both the samples had 33,247,454 bp of total assembled bases and 38,292 of transcripts. The GC percent of assembled transcripts was 44.79%, an average read length was 800 bp and N 50 value was 1186 bp. Species-specific distribution using BLAST X (Nr), showed the highest Blast hits with Sesamum indicum. Out of 23,346 transcripts, 87% of transcripts annotated in UniProt KB (Universal Protein Resource KnowledgeBase) database and only 0.21% of transcripts were annotated in TAIR (The Arabidopsis Information Resources). Biological processes gene ontology classified based on Blast2GO showed, out of 6853 transcripts, 1370 of transcripts were represented by terpenoid biosynthetic pathway, which involved in secondary metabolite andrographolide biosynthesis. The heat map showed 1016 transcripts were differentially expressed between two kalmegh genotypes, in which nine important differentially expressed transcripts related to MEP (2C methyl- d -erythritol 4-phosphate) and MVA (Mevalonic acid) andrographolide biosynthesis pathways such as, geranyl diphosphate synthase small subunit, Isopentenyl-diphosphate delta-isomerase i-like, 4, 13-hydroxy-3-methylglutaryl-coenzyme a reductase etc. were upregulated in IC 520361 as compared to Anand Local, which were validated through RT-qPCR. The highest expression of gene 13-hydroxy-3-methylglutaryl-coenzyme a reductase (HMGR) was reported, which is responsible for accumulation of andrographolide in leaf. This comparative transcriptome analysis confirmed the expression level of genes were higher in accession IC 520361 as compare to Anand Local related to andrographolide biosynthesis pathways i.e. MEP and MVA. These up-regulated genes could be over-expressed to enhance the andrographolide content using genetic engineering of these metabolic pathways. It will also give an idea to the breeder for development of molecular markers for direct screening of the genotypes. Electronic supplementary material The online version of this article (10.1007/s13205-020-02511-y) contai...

Comparative transcriptome analyses of differentSalvia miltiorrhizavarieties during the accumulation of tanshinones

“…For instance, DEGs in two different chemotypes of Cinnamomum camphora were mainly associated with carbohydrate metabolism, signal transduction, and terpenoid biosynthesis, and these biological processes-related DEGs resulted in chemotype variation in C. camphora (Chen et al, 2018a). In Andrographis paniculata, the biosynthesis of diterpenoid andrographolide involved the processes such as citrate cycle, carbon fixation, and oxidative phosphorylation in addition to terpenoid biosynthesis (Patel et al, 2020). Transcriptional studies of Daucus carota with different flavonoids concentrations revealed that the accumulation of flavonoids was related to flavonoid biosynthesis pathway, endogenous signaling and other secondary metabolite biosynthesis pathways (Meng, Clausen & Rasmussen, 2020).…”

“…f.) Nees. with significant differences in diterpene andrographolide contents revealed that the expression levels of genes related to the biosynthesis of secondary metabolite andrographolide were higher in the genotype with high andrographolide content as compared to that in the low content group (Patel et al, 2020). Matricaria recutita and Chamaemelum nobile are two chamomile species with different chemical compositions, the comparative analysis of their transcriptome revealed that different gene regulation in the synthesis of terpenoid may contribute to the variation in terpenes types and concentrations in these two species.…”

Isolation, Characterization, and Expression Analysis of NAC Transcription Factor from Andrographis paniculata (Burm. f.) Nees and Their Role in Andrographolide Production

“…Based on the literature search, the andrographolide biosynthesis pathways, such as MVA (mevalonate pathway) and MEP (2-C-methyl-D-erythritol 4-phosphate) pathways, were examined. Enzyme genes associated with these pathways, including HMGR (XM_051267731.1), HDS (XM_051264732.1), MVK (XM_051288144.1), DXS (NM_001422027.1), and DXR (XM_051280679.1), were also selected for expression analysis under ABA treatment [73][74][75][76]. These genes were previously reported to be strongly induced during the higher accumulation of andrographolide content.…”

“…The biosynthesis of andrographolide involves the formation of geranylgeranyl diphosphate as a precursor, followed by enzymatic steps leading to the conversion of entditerpenol (ent-copalyl-PP) into andrographolide [74]. The schematic representation of the proposed andrographolide pathway is provided in Figure 4.…”

“…Notably, andrographolide, the principal secondary metabolite from the plant, exhibited a considerable correlation with ApNAC02 and ApNAC21 22, indicating their involvement in the biosynthesis of andrographolide [79]. The biosynthesis of andrographolide involves the formation of geranylgeranyl diphosphate as a precursor, followed by enzymatic steps leading to the conversion of entditerpenol (ent-copalyl-PP) into andrographolide [74]. The schematic representation of HDR is 4-hydroxy-3-methylbut-2-enyldiphosphatereductase; IPP is isopentenyl diphosphate isomerase; GGPPS is geranylgeranyl diphosphate synthase; ent-CPS is ent-copalyl diphosphate synthase; ent-KS is ent-kaurene synthase; ent-KO is ent-kaurene oxidase; ent-KAO is entkaurenoic acid oxidase; CYP450 is cytochrome P450 monooxygenase; GT is glycosyltransferase.…”