TheEruca sativagenome and transcriptome: A targeted analysis of sulfur metabolism and glucosinolate biosynthesis pre and postharvest

Abstract

Rocket (Eruca sativa) is a source of health-related metabolites called glucosinolates (GSLs) and isothiocyanates (ITCs) but little is known of the genetic and transcriptomic mechanisms responsible for regulating pre and postharvest accumulations. We present the first de novo reference genome assembly and annotation, with ontogenic and postharvest transcriptome data relating to sulfur assimilation, transport, and utilization. Diverse gene expression patterns related to sulfur metabolism and GSL biosynthesis are present between inbred lines of rocket. A clear pattern of differential expression determines GSL abundance and the formation of hydrolysis products. One breeding line sustained GSL accumulation and hydrolysis product formation throughout storage. Copies of MYB28, SLIM1, SDI1 and ESM1 orthologs have increased and differential expression postharvest, and are associated with GSLs and hydrolysis product formation. Two glucosinolate transporter gene orthologs (GTR2) were found to be associated with increased GSL accumulations.

Genotypes of Eruca vesicaria subsp. sativa grown in contrasting field environments differ on transcriptomic and metabolomic levels, significantly impacting nutritional quality

“…This compares with only 0.2 mg g -1 dw for the corresponding Italygrown plant sample. This difference in sugar concentrations is consistent with previous observations (Bell et al, 2022).…”

“…Six lines of 'salad' rocket were selected from a segregating F 2 mapping population of 139 lines based on their high and low abundances of GSLs across two growing locations (Bell et al, 2022). The selected lines were referred to as 21 (low GSL), 25 (low GSL), 68 (high GSL), 72 (low GSL), 112 (high GSL), and 130 (high GSL).…”

“…The accumulation of sugars in leaves is closely linked with environment (Song et al, 2017), however the regulation of sugar metabolism in response to environmental factors remains unclear. Eruca itself is a Mediterranean species and has become naturalized in colder regions of the world, leading researchers to hypothesize that the higher concentrations of sugars observed in the UK may be due to a cold stress response (Bell et al, 2022). As demonstrated by Romań et al (2018), free sugars themselves may also act as inhibitors of myrosinase, blocking GSL hydrolysis and reducing the abundance of GHPs produced.…”

“…Based on previous field trial observations (Bell et al, 2022) we also hypothesised that UK-grown plants would contain significantly higher concentrations of sugars compared with Italy-grown. The rationale for this hypothesis was based upon reports from growers and processors that rocket leaves produced in the UK are typically of a lower quality (lacking pungency and postharvest longevity) than those from Italy owing to suboptimal pre-harvest temperatures and humidity; this in turn leads to greater levels of disease and stress burden, increasing respiration and the increased need for sugars in primary metabolism (Sami et al, 2016).…”

In vitro application of Eruca vesicaria subsp. sativa leaf extracts and associated metabolites reduces the growth of Oomycota species involved in Kiwifruit Vine Decline Syndrome

“…The major hydrolysis products produced by Eruca leaves, sativin and erucin, were investigated and extracted according to the protocol of Bell et al (2020). GC-MS was performed on an Agilent 7693/5975 GC-MS with autosampler (Agilent, Manchester, UK).…”