title: Induction of secondary metabolite production by UV-C radiation in Vitis vinifera L. Öküzgözü callus cultures.
abstract: BACKGROUND
  The aim of the present work was to examine the role of UV-C irradiation on the production of secondary metabolites (total phenolic, total flavanols, total flavonols, catechin, ferulic acid and trans-resveratrol in phenolic compounds and α-, β-, γ- δ-tocopherols) in callus cultures. Studies on the effects of UV-C treatment on callus culture are seldom and generally focused on UV-B. However UV-C radiation play an important role in accumule secondary metabolites.
  
  
  RESULTS
  In this study, callus cultures from Öküzgözü grape cultivar were initiated from leaf petiole explants. Calli formed after 6 weeks on the medium supplemented with 0.5 mg L-1 benzylaminopurine (BA), 0.5 mg L-1 indole acetic acid (IAA) on B5 media. Callus tissues were exposed to UV-C irradiation at 10, 20 and 30 cm distances from the UV source for 5 and 10 minutes and samples were collected at hours 0, 24 and 48.
  
  
  CONCLUSIONS
  The greatest total phenolic content (155.14 mg 100 g-1) was detected in calli exposed to UV-C for 5 min from 30 cm distance and sampled after 24 h. 24 h and 48 h incubation times, 30 cm and 5 min were the most appropriate combination of UV-C application in total flavanol content. Maximum total flavonol content (7.12 mg 100 g-1) was obtained on 0 h, 5 min and 20 cm combination. The highest (+)- catechin accumulation (8.89 mg g-1) was found in calli with 10 min UV-C application from 30 cm distance and sampled after 48 h. Ferulic acid content increased 6 fold in Öküzgözü callus cultures (31.37 μg g-1) compared to the control group. The greatest trans-resveratrol content (8.43 μg g-1) was detected in calli exposed to UV-C for 5 min from 30 cm distance and sampled after 24 h. The highest α-tocopherol concentration was found in calli exposed to UV-C for 10 min from 30 cm distance and sampled after 24 h. As a conclusion, it was showed that UV-C radiation had remarkable promoting effects on the accumulation of secondary metabolites in the calli of Öküzgözü grape cultivar.
authors.forename: Emine Sema
authors.initials: ES
authors.lastname: Cetin
mesh_terms: D002392:Catechin / Q000032:analysis; D002845:Chromatography; D003373:Coumaric Acids / Q000032:analysis; D018556:Crops, Agricultural / Q000502:physiology / Q000528:radiation effects*; D005419:Flavonoids / Q000032:analysis; D044948:Flavonols / Q000032:analysis; D010636:Phenols / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects*; D058439:Plant Somatic Embryogenesis Techniques / Q000379:methods*; D000077185:Resveratrol; D064210:Secondary Metabolism / Q000502:physiology / Q000528:radiation effects*; D013267:Stilbenes / Q000032:analysis; D024505:Tocopherols / Q000032:analysis; D014466:Ultraviolet Rays; D027843:Vitis / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D003373:Coumaric Acids; D005419:Flavonoids; D044948:Flavonols; D010636:Phenols; D013267:Stilbenes; C404987:flavan-3-ol; D002392:Catechin; C004999:ferulic acid; D000077185:Resveratrol; D024505:Tocopherols