De novo transcriptome analysis and glucosinolate profiling in watercress (Nasturtium officinale R. Br.)

Abstract

BackgroundWatercress (Nasturtium officinale R. Br.) is an aquatic herb species that is a rich source of secondary metabolites such as glucosinolates. Among these glucosinolates, watercress contains high amounts of gluconasturtiin (2-phenethyl glucosinolate) and its hydrolysis product, 2-phennethyl isothiocyanate, which plays a role in suppressing tumor growth. However, the use of N. officinale as a source of herbal medicines is currently limited due to insufficient genomic and physiological information.ResultsTo acquire precise information on glucosinolate biosynthesis in N. officinale, we performed a comprehensive analysis of the transcriptome and metabolome of different organs of N. officinale. Transcriptome analysis of N. officinale seedlings yielded 69,570,892 raw reads. These reads were assembled into 69,635 transcripts, 64,876 of which were annotated to transcripts in public databases. On the basis of the functional annotation of N. officinale, we identified 33 candidate genes encoding enzymes related to glucosinolate biosynthetic pathways and analyzed the expression of these genes in the leaves, stems, roots, flowers, and seeds of N. officinale. The expression of NoMYB28 and NoMYB29, the main regulators of aliphatic glucosinolate biosynthesis, was highest in the stems, whereas the key regulators of indolic glucosinolate biosynthesis, such as NoDof1.1, NoMYB34, NoMYB51, and NoMYB122, were strongly expressed in the roots. Most glucosinolate biosynthetic genes were highly expressed in the flowers. HPLC analysis enabled us to detect eight glucosinolates in the different organs of N. officinale. Among these glucosinolates, the level of gluconasturtiin was considerably higher than any other glucosinolate in individual organs, and the amount of total glucosinolates was highest in the flower.ConclusionsThis study has enhanced our understanding of functional genomics of N. officinale, including the glucosinolate biosynthetic pathways of this plant. Ultimately, our data will be helpful for further research on watercress bio-engineering and better strategies for exploiting its anti-carcinogenic properties.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3792-5) contains supplementary material, which is available to authorized users.

Expression profiles of glucosinolate biosynthetic genes in turnip (Brassica rapa var. rapa) at different developmental stages and effect of transformed flavin‐containing monooxygenase genes on hairy root glucosinolate content

“…This may be related to the early accumulation of GSLs in turnip tubers. The accumulation patterns of most aliphatic GSLs coincided with the expression patterns of genes related to side chain formation, which may partly reflect the accumulation of GSLs, as has been reported previously . However, there is still no correlation between the expression profiles of some candidate genes and the level of GSL, which may due to the role of transport of GSL between different tissues, and the direct relationship between gene expression and GSL content variation requires more validation.…”

Accumulation of Anthocyanins through Overexpression of AtPAP1 in Solanum nigrum Lin. (Black Nightshade)

“…The deduced amino acid sequences of the retrieved genes were further analyzed for homology using BLAST in the NCBI GenBank database (https://blast.ncbi.nlm.nih.gov/Blast.cgi). The genes with a maximum identity were used for the further transcriptional study [16,17].…”

Watercress, as a Functional Food, with Protective Effects on Human Health Against Oxidative Stress: A Review Study

“…Nasturtium officinale R. Br. Species, was primarily found in Europe and Asia [8], and introduced into Australia, North America and South America [10].Therefore, this plant contains a traditional composition of vitamins B1, B2, B3, B5, B6, C, E, pro-vitamin A, folic acid and some minerals (copper, zinc, magnesium, calcium manganese, iron, phosphorus, andiodine), carbohydrates (fibers), lipids, and proteins [8] [14]. Phenyethylisothiocyanate, called PEITC, which is also a bioactive compound present in high level of concentrations of watercress, as its precursor'sglucosinolate.…”

“…As a member of the Brassicaceae, watercress is related to cruciferous vegetables, such as broccoli, cabbage, radish, brussels, sprouts as well as mustard and kale [4]. The consumption of vegetables from Brassicaceae family are suggested to benefit human health, which are rich sources of sulfurcontaining compounds called glucosinolates that impart a pungent aroma and a spicy or bitter taste [5] and phenylethylisothiocyanate (PEITC), which has been associated to reduce risk of cancer and oxidative stress [3][6] [7] Watercress contains some vitamins such as A and E, minerals (iron and copper), and is also rich in bioactive compounds, named polyphenols, glucosinolates and PEITC [8] [9]. Therefore, this food can be collected from its natural habitats and used as a fresh or dried plant [10] and, its leaves have beenused in folk medicine as a diuretic, expectorant, hypoglycemic and many chronic diseases [7].…”