Identification and Variation of Major Aliphatic Glucosinolates in Doubled Haploid Lines of Radish (Raphanus sativus L.)

Abstract

The aim of this study was to determine the concentration of glucoraphenin (GRE) and glucoraphasatin (GRH) from 41 doubled haploid (DH) lines of radish (Raphanus sativus L.) cultivar obtained by isolated microspore culture. Microspores from flower buds (4.0 +/- 0.5 mm in length) were cultured in Nitsch and Nitsch medium, and microspore-derived embryos were regenerated into complete plantlets in Murashige and Skoog medium. The average embryo yield was 5.0 +/- 2.9 per petri dish. Seeds obtained by bud pollination from the DH lines were planted and leaves of 4-week old seedlings were used for analysis of glucosinolate (GSL) content. In order to determine the GSL content, GRE from seeds and GRH from the roots were extracted and purified to 96.2 and 71.0%, respectively. The amount of GRH markedly varied among the DH lines, ranging from 2.6 to 31.5 mg per gram dry weight. GRH contents were reduced by as much as 14.1% or increased by up to 171.2% compared with the donor plant. There was as much as a 6.1-fold difference in the amount of GRE between the DH lines. Among the 41 DH lines tested, the sum of GRE and GRH contents were significantly reduced in 14 DH lines compared to the donor plant (p = 0.95), whereas the contents were increased in only three DH lines. Our results will be useful for breeding radish genotypes with low and high content of GSL, and the DH lines developed in this study will be useful germplasm for elucidating the regulation of the biosynthesis of aliphatic GSLs in radish plants.