title: Comparative Transcriptome Analyses Reveal a Special Glucosinolate Metabolism Mechanism inBrassica alboglabraSprouts.
abstract: Brassicasprouts contain abundant phytochemicals, especially glucosinolates (GSs). Various methods have been used to enhance GS content in sprouts. However, the molecular basis of GS metabolism in sprouts remains an open question. Here we employed RNA-seq analysis to compare the transcriptomes of high-GS (JL-08) and low-GS (JL-09)Brassica alboglabrasprouts. Paired-end Illumina RNA-seq reads were generated and mapped to theBrassica oleraceareference genome. The differentially expressed genes were analyzed between JL-08 and JL-09. Among these, 1477 genes were up-regulated and 1239 down-regulated in JL-09 compared with JL-08. Enrichment analysis of these differentially expressed genes showed that the GS biosynthesis had the smallest enrichment factor and the highestQ-value of all metabolic pathways in Kyoto Encyclopedia of Genes and Genomes database, indicating the main metabolic difference between JL-08 and JL-09 is the GS biosynthetic pathway. Thirty-seven genes of the sequenced data were annotated as putatively involved in GS biosynthesis, degradation, and regulation, of which 11 were differentially expressed in JL-08 and JL-09. The expression level of GS degradation enzyme myrosinase in high-GS JL-08 was lower compared with low-GS JL-09. Surprisingly, in high-GS JL-08, the expression levels of GS biosynthesis genes were also lower than those in low-GS JL-09. As the GS contents in sprouts are determined by dynamic equilibrium of seed stored GS mobilization,de novosynthesis, degradation, and extra transport, the result of this study leads us to suggest that efforts to increase GS content should focus on either raising GS content in seeds or decreasing myrosinase activity, rather than improving the expression level of GS biosynthesis genes in sprouts.
authors.affiliation: Department of Horticulture, Fujian Agriculture and Forestry UniversityFuzhou, China; Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry UniversityFuzhou, China.
authors.forename: Rongfang
authors.initials: R
authors.lastname: Guo
authors.affiliation: Department of Horticulture, Fujian Agriculture and Forestry University Fuzhou, China.
authors.forename: Zhongkai
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Horticulture, Fujian Agriculture and Forestry University Fuzhou, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Horticulture, Fujian Agriculture and Forestry University Fuzhou, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Horticulture, Fujian Agriculture and Forestry UniversityFuzhou, China; Institut de la Recherche Interdisciplinaire de ToulouseToulouse, France.
authors.forename: Xu
authors.initials: X
authors.lastname: XuHan
authors.affiliation: Department of Horticulture, Fujian Agriculture and Forestry UniversityFuzhou, China; Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry UniversityFuzhou, China.
authors.forename: Zhongxiong
authors.initials: Z
authors.lastname: Lai
keywords: Brassica alboglabra; Chinese kale; glucosinolate; myrosinase; sprouts