Evaluation of glucosinolate content in radish (Raphanus sp.) germplasm

 

Glucosinolate (GSL) is a secondary metabolite and its composition and content is influenced by genotype, climate and cultivation conditions. Raphanus species, including radish (Raphanus sativus L.), wild radish (R. raphanistrum) and wild radish (R. sativus subsp. raphanistroides) of each 32, 4 and 21 accessions were analyzed for their GSL content using leaf and root tissues, respectively. A total of thirteen GSLs, namely progoitrin, glucoraphanin, sinigrin, glucoalyssin, gluconapoleiferin, gluconapin, 4-hydroxyglucobrassicin, glucobrassicanapin, glucoraphasatin, glucobrassicin, 4-methoxyglucobrassicin, gluconasturtiin, and neoglucobrasscin were identified in the both tissues. Glucoraphasatin, glucobrassicin, and sinigrin were identified as the major glucosinolates in radish species. Glucoraphasatin was higher in root as compared to leaves in all the species. Glucoraphasatin was the highest in R. raphanistrum (45.9µmol·g^-1) root followed by R. sativus subsp. raphanistroides (45.1µmol·g^-1) and the lowest (9.7µmol·g^-1) in R. raphanistrum leaves. Glucobrassicin was identified the highest (4.0µmol·g^-1) in R. sativus leaves followed by glucoraphasatin (3.6µmol·g^-1). Average total GSL was the highest (49.4µmol·g^-1) in root of R. raphanistrum followed by R. sativus subsp. raphanistroides (47.6µmol·g^-1). Total GSL was varied from 2.8µmol·g^-1 (IT102414) to 81.9µmol·g^-1 (K036841) of the root of R. sativus and R. sativus subsp. raphanistroides, respectively whereas in leaves, it was varied from 1.3µmol·g^-1 (K226454) to 45.1µmol·g^-1 (K036846) of R. sativus and R. sativus subsp. raphanistroides, respectively. Root tissues of R. raphanistrum and R. sativus subsp. raphanistroides exhibited higher total GSL than the leaves of Raphanus species. This result is useful to assist future radish breeding program particularly on addressing the beneficial glucosinolate in crops.

Acknowledgements: This research was supported by RDA R & D.

Keywords: Glucosinolates, Raphanus species, secondary metabolites, germplasms.

References:

[1] Ishida M, Hara M, Fukino N, Kakizaki T, Morimitsu Y. Glucosinolate metabolism, functionality and breeding for the improvement of Brassicaceae vegetables. Breed Sci 2014; 64: 48 – 59.