Double haploid production using microspore culture is a useful breeding method in the modulation of glucosinolates contents in Radish (Raphanus sativus L.).

The production of double haploids ("DH") by microspore-derived embryos is one of the best breeding methods to generate new varieties with better traits and stable genetic background. In the previous study, radish 'DH' lines were generated with a different range of glucosinolate (GSL) contents, ranging from low to high levels of GSL. In this study, we performed metabolic and transcriptional profiling to elucidate the regulatory system behind the GSL biosynthesis process using the 'DH' radish lines. Four individual 'DH' lines were selected, of which two lines named 'HH' had high GSL content, while the other two lines, 'LL', had low GSL content. HPLC analysis in the vegetative (leaf and root) and reproductive tissue (seed) was detected seven GSL compounds from radish. Among seven GSLs, glucoraphasatin (GRH) occupied the largest proportion of total GSLs in both leaf and root tissues, while glucoraphenin (GRE) was taking a place as the major GSL in radish seeds. Six major genes (RsBCAT4, RsIPMDH1, RsCYP79F1, RsCYP83A1, RsUGT74B1, and RsGRS1) representing the major biosynthesis of aliphatic GSLs were selected for qRT-PCR analysis. Heat map analysis based on Pearson correlation coefficient showed that RsBCAT4, RsIPMDH1, RsCYP79F1, and RsCYP83A1 were positively correlated with the amount of GRH in leaf tissue. Meanwhile, RsGRS1 showed a strong correlation with the amount of GRH and total aliphatic GSLs in both leaf and root tissues. By using the 'DH' radish lines, this study revealed that regardless of tissues of radish, accumulation of total GSL is strongly affected by the RsGRS1 and also positively supported by the other biosynthetic genes like RsBCAT4, RsIPMDH1, RsCYP79F1, and RsCYP83A1. [ABSTRACT FROM AUTHOR]