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Carrot is a major source of provitamin A in a human diet. Two of the most important traits for carrot breeding are carotenoid contents and root color. To examine genomic regions related to these traits and develop DNA markers for carrot breeding, we performed an association analysis based on a general liner model using genome-wide single nucleotide polymorphism (SNPs) in two F2 populations, both derived from crosses of orange root carrots bred in Japan. The analysis revealed 21 significant quantitative trait loci (QTLs). To validate the detection of the QTLs, we also performed a QTL analysis based on a composite interval mapping of these populations and detected 32 QTLs. Eleven of the QTLs were detected by both the association and QTL analyses. The physical position of some QTLs suggested two possible candidate genes, an Orange (Or) gene for visual color evaluation, and the α- and β-carotene contents and a chromoplast-specific lycopene β-cyclase (CYC-B) gene for the β/α carotene ratio. A KASP marker developed on the Or distinguished a quantitative color difference in a different, related breeding line. The detected QTLs and the DNA marker will contribute to carrot breeding and the understanding of carotenoid biosynthesis and accumulation in orange carrots. [ABSTRACT FROM AUTHOR]

Their high adaptability to difficult coastal conditions makes mangrove trees a valuable resource and an interesting model system for understanding the molecular mechanisms underlying stress tolerance and adaptation of plants to the stressful environmental conditions. In this study, we used RNA sequencing (RNA-Seq) for de novo assembling and characterizing the Bruguiera gymnorhiza (L.) Lamk leaf transcriptome. B. gymnorhiza is one of the most widely distributed mangrove species from the biggest family of mangroves; Rhizophoraceae. The de novo assembly was followed by functional annotations and identification of individual transcripts and gene families that are involved in abiotic stress response. We then compared the genome-wide expression profiles between two populations of B. gymnorhiza, growing under different levels of stress, in their natural habitats. One population living in high salinity environment, in the shore of the Pacific Ocean- Japan, and the other population living about one kilometre farther from the ocean, and next to the estuary of a river; in less saline and more brackish condition. Many genes involved in response to salt and osmotic stress, showed elevated expression levels in trees growing next to the ocean in high salinity condition. Validation of these genes may contribute to future salt-resistance research in mangroves and other woody plants. Furthermore, the sequences and transcriptome data provided in this study are valuable scientific resources for future comparative transcriptome research in plants growing under stressful conditions. [ABSTRACT FROM AUTHOR]