Project description:Bitter pit is the most important physiological disorder affecting apples. In order to ascertain the genetic bases of its incidence in apple fruit, a mapping population of ‘Braeburn’ (susceptible to bitter pit) × ‘Cameo’ (resistant to bitter pit) cultivars was used to map the trait over two growing seasons. RNA-Seq on pools of RNA extracted from fruits of three resistant and three susceptible to bitter pit progenies at post-fertilization and full maturity stages, permitted us to identify a number of candidate genes underlying genetic resistance/susceptibility to bitter pit.
Project description:T2R bitter receptors, encoded by Tas2r genes, are not only critical for bitter taste signal transduction but also important for defense against bacteria and parasites. However, little is known about whether and how Tas2r gene expression are regulated. Here, using single-cell assays for transposase-accessible chromatin with sequencing (scATAC-seq), we found that the chromatin accessibility of Tas2rs was highly cell type specific and lipopolysaccharide (LPS)-induced inflammation increased the accessibility of many Tas2rs. scATAC-seq also revealed substantial chromatin remodeling in immune response genes in taste tissue stem cells, suggesting potential long-term effects. Together, our results suggest an epigenetic mechanism connecting inflammation, Tas2r gene regulation, and altered bitter taste, which may explain heightened bitter taste that can occur with infections and cancer treatments.
Project description:We generated 95.37 Gb of high-quality sequencing data (~7.95 Gb per sample). The analysis showed differences of transcriptomes between the common white sweet quinoa and the yellow bitter quinoa. We identified numerous differentially expressed genes that exhibited distinct expression patterns. These genes have known or potential roles in taste of quinoa fruit.Therefore, we are appealing candidates for further investigation of the gene expression and associated regulatory mechanisms related to the accumulation of bitter saponins in C. quinoa fruits.
Project description:<p><strong>INTRODUCTION: </strong>Bitter melon (Momordica charantia, Cucurbitaceae) is a popular edible medicinal plant, which has been used as a botanical dietary supplement for the treatment of diabetes and obesity in Chinese folk medicine. Previously, our team has proved that cucurbitanes triterpenoid were involved in bitter melon's anti-diabetic effects as well as on increasing energy expenditure. The triterpenoids composition can however be influenced by changes of varieties or habitats.</p><p><strong>OBJECTIVES:</strong> To clarify the significance of bioactive metabolites diversity among different bitter melons and to provide a guideline for selection of bitter melon varieties, an exploratory study was carried out using a UHPLC-HRMS based metabolomic study to identify chemotypes.</p><p><strong>METHODS:</strong> Metabolites of 55 seed samples of bitter melon collected in different parts of China were profiled by UHPLC-HRMS. The profiling data were analysed with multivariate (MVA) statistical methods. Principle component analysis (PCA) and hierarchical cluster analysis (HCA) were applied for sample differentiation. Marker compounds were identified by comparing spectroscopic data with isolated compounds, and additional triterpenes were putatively identified by propagating annotations through a molecular network (MN) generated from UHPLC-HRMS & MS/MS metabolite profiling.</p><p><strong>RESULTS:</strong> PCA and HCA provided a good discrimination between bitter melon samples from various origins in China. This study revealed for the first time the existence of two chemotypes of bitter melon. Marker compounds of those two chemotypes were identified at different MSI levels. The combined results of MN and MVA demonstrated that the two chemotypes mainly differ in their richness in cucurbitane versus oleanane triterpenoid glycosides (CTGs vs. OTGs).</p><p><strong>CONCLUSION:</strong> Our finding revealed a clear chemotype distribution of bioactive components across bitter melon varieties. While bioactivities of individual CTGs and OTGs still need to be investigated in more depth, our results could help in future the selection of bitter melon varieties with optimised metabolites profile for an improved management of diabetes with this popular edible Chinese folk medicine.</p>
Project description:Fruit taste is determined by sugars, acids and in some species, bitter chemicals. Attraction of seed-dispersing organisms in nature and breeding for consumer preferences requires reduced fruit bitterness. A key metabolic shift during ripening prevents tomato fruit bitterness by eliminating α-tomatine, a renowned defence-associated Solanum alkaloid. Here, we combined fine mapping with information from 150 re-sequenced genomes and genotyping a 650 tomato core collection to identify nine bitter-tasting accessions including the ‘high α-tomatine’ Peruvian landraces reported by Rick and colleagues (1994). These ‘bitter’ accessions contain a deletion in GORKY, a nitrate/peptide family (NPF) transporter mediating α-tomatine subcellular localization during fruit ripening. GORKY exports α-tomatine and its derivatives from the vacuole to the cytosol and this facilitates the conversion of the entire α-tomatine pool to non-bitter forms, rendering the fruit palatable. Hence, GORKY activity was a significant innovation in the process of tomato fruit domestication and breeding. The experiment was carried out to further prove that GORKY is localized to tonoplast in ripe fruit.