Transcriptome analysis of the curry tree (Bergera koenigii L., Rutaceae) during leaf development

Abstract

The curry tree (Bergera koenigii L.) is a widely cultivated plant used in South Asian cooking. Next-generation sequencing was used to generate the transcriptome of the curry leaf to detect changes in gene expression during leaf development, such as those genes involved in the production of oils which lend the leaf its characteristic taste, aroma, and medicinal properties. Using abundance estimation (RSEM) and differential expression analysis, genes that were significantly differentially expressed were identified. The transcriptome was annotated with BLASTx using the non-redundant (nr) protein database, and Gene Ontology (GO) terms were assigned based on the top BLAST hit using Blast2GO. Lastly, functional enrichment of the assigned GO terms was analyzed for genes that were significantly differentially expressed. Of the most enriched GO categories, pathways involved in cell wall, membrane, and lignin synthesis were found to be most upregulated in immature leaf tissue, possibly due to the growth and expansion of the leaf tissue. Terpene synthases, which synthesize monoterpenes and sesquiterpenes, which comprise much of the curry essential oil, were found to be significantly upregulated in mature leaf tissue, suggesting that oil production increases later in leaf development. Enzymes involved in pigment production were also significantly upregulated in mature leaves. The findings were based on computational estimates of gene expression from RNA-seq data, and further study is warranted to validate these results using targeted techniques, such as quantitative PCR.

A comprehensive review on genomic resources in medicinally and industrially important major spices for future breeding programs: Status, utility and challenges

“…In curry leaf ( Murraya koenigii ), genes encoded for terpene synthases were functionally characterized to ascertain their role in the synthesis of leaf volatiles by wide transcriptome studies ( Meena et al, 2017 ). Further studies unlock gene families for polyketide synthases, prenyltransferases, methyltransferases, and cytochrome P450s involved in the production of carbazole alkaloids and leaf development ( Meena et al, 2017 ; Shivakumar et al, 2019 ). A tissue-specific transcriptome identifies genes involved in terpenoid and phenylpropanoid metabolism in ferula species ( Amini et al, 2019 ).…”

Curry tree, Murraya koenigii (L.) (Spreng): A review and future prospects using applications of next generation sequencing technology

“…Until this study, only a few nuclear genes, complete chloroplast genome 37 , and a transcriptome 38 in mature leaves had been sequenced for the curry tree; this study adds 57,383 newly sequenced transcripts (including multiple transcriptional isoforms of the same gene), contributing to a new understanding of the molecular genetics of the curry leaf development. 39 .…”

Transcriptome analysis associated with polysaccharide synthesis and their antioxidant activity in Cyclocarya paliurus leaves of different developmental stages

“…Recently, temporal gene expression profiles that characterize the time-dynamics of expression of specific genes related to the secondary metabolites of plants have attracted increasing scientific attention (Li et al, 2016;Liu et al, 2015;Mueller, Chiou & Leng, 2008;Shivakumar, Johnson & Zimmer, 2019;Sweetman et al, 2012;Wong et al, 2017). For example, Li et al (2016) reported that Camellia sinensis leaf transcriptomes differed among three growth stages, which is also the case for differentially expressed unigenes related to metabolic pathways, biosynthesis of secondary metabolites, phenylpropanoid biosynthesis, and carbon fixation during photosynthesis.…”

“…For example, Li et al (2016) reported that Camellia sinensis leaf transcriptomes differed among three growth stages, which is also the case for differentially expressed unigenes related to metabolic pathways, biosynthesis of secondary metabolites, phenylpropanoid biosynthesis, and carbon fixation during photosynthesis. Shivakumar, Johnson & Zimmer (2019) identified differentially expressed genes (DEGs) involved in oil production using transcriptome analysis of the leaves of Bergera koenigii at different developmental stages. However, the temporal patterns of the gene expression of polysaccharide synthesis in C. paliurus at different leaf developmental stages have not been reported so far.…”