Integrated analysis of multi-omics and fine-mapping reveals a candidate gene regulating pericarp color and flavonoids accumulation in wax gourd (Benincasa hispida).

Wax gourd (Benincasa hispida), a popular fruit of the Cucurbitaceae (cucurbits) family, contains many nutrients with health benefits and is widely grown in China and other tropical areas. In this study, a wax gourd mutant hfc12 with light-color pericarp was obtained through ethane methylsulfonate (EMS) mutagenesis. Integrative analysis of the metabolome and transcriptome identified 31 differentially accumulated flavonoids (DAFs; flavonoids or flavonoid glycosides) and 828 differentially expressed genes (DEGs) between the hfc12 mutant and wild-type 'BWT'. Furthermore, BSA-seq and kompetitive allele specific PCR (KASP) analysis suggested that the light-color pericarp and higher flavonoid content was controlled by a single gene BhiPRR6 (Bhi12M000742), a typical two-component system (TCS) pseudo-response regulator (PRR). Genetic analysis detected only one nonsynonymous mutation (C-T) in the second exon region of the BhiPRR6. Weighted correlation network analysis (WGCNA) identified the downstream target genes of BhiPRR6, probably regulated by light and were intermediated in the regulatory enzyme reaction of flavonoid biosynthetic pathway. Thus, these results speculated that the transcription factor BhiPRR6, interacting with multiple genes, regulates the absorption of light signals and thereby changes the pericarp color and synthesis of flavonoids in wax gourd.

Evaluation of the uptake capacities of heavy metals in Chinese cabbage.

Heavy metal (HM) contamination in soil result in second pollution damage to Chinese cabbage, leading to deleterious health impacts. To elucidate the common transfer and accumulation characteristics of HMs in Chinese cabbage cultivar is important for safety breeding and consumption. In this case, concentrations and transfer capacities of HMs (Cd, Cr, Hg, Pb and As) in 35 common Chinese cabbage genotypes and their genotypic difference were investigated in this work. Results indicate that Chinese cabbage cultivar was more susceptible to Cd pollution, Hg was easily sifted from underground part to aerial part, Cr and Pb have similar enrichment and translocation characteristics, and Chinese cabbage cultivar had tolerance to As toxicity to some extent. Moreover, genotypic difference in HM accumulation in different parts of Chinese cabbage cultivar was also observed, and for edible part, followed by Hg>As>Cd>Pb>Cr. Referring to overall HM pollution level and biomass yield of edible part of 35 tested Chinese cabbages, B18, B6, B2 and B3 could be considered as the potential HMs pollution-safe Chinese cabbage cultivars. Information founded in this work may be used to provide referential strategies and methods to minimize the influx of HMs pollutants to human being through consumption and cultivation of Chinese cabbages.