title: UV-B irradiation changes specifically the secondary metabolite profile in broccoli sprouts: induced signaling overlaps with defense response to biotic stressors.
abstract: Only a few environmental factors have such a pronounced effect on plant growth and development as ultraviolet light (UV). Concerns have arisen due to increased UV-B radiation reaching the Earth's surface as a result of stratospheric ozone depletion. Ecologically relevant low to moderate UV-B doses (0.3-1 kJ m(-2) d(-1)) were applied to sprouts of the important vegetable crop Brassica oleracea var. italica (broccoli), and eco-physiological responses such as accumulation of non-volatile secondary metabolites were related to transcriptional responses with Agilent One-Color Gene Expression Microarray analysis using the 2×204 k format Brassica microarray. UV-B radiation effects have usually been linked to increases in phenolic compounds. As expected, the flavonoids kaempferol and quercetin accumulated in broccoli sprouts (the aerial part of the seedlings) 24 h after UV-B treatment. A new finding is the specific UV-B-mediated induction of glucosinolates (GS), especially of 4-methylsulfinylbutyl GS and 4-methoxy-indol-3-ylmethyl GS, while carotenoids and Chl levels remained unaffected. Accumulation of defensive GS metabolites was accompanied by increased expression of genes associated with salicylate and jasmonic acid signaling defense pathways and up-regulation of genes responsive to fungal and bacterial pathogens. Concomitantly, plant pre-exposure to moderate UV-B doses had negative effects on the performance of the caterpillar Pieris brassicae (L.) and on the population growth of the aphid Myzus persicae (Sulzer). Moreover, insect-specific induction of GS in broccoli sprouts was affected by UV-B pre-treatment.
authors: Leibniz-Institute of Vegetable and Ornamental Crops Großbeeren/Erfurt e.V., Department of Quality, Theodor-Echtermeyer-Weg 1, D-14979 Großbeeren, Germany. inga@entomology.de
authors: Inga
authors: I
authors: Mewis
authors: Monika
authors: M
authors: Schreiner
authors: Chau Nhi
authors: CN
authors: Nguyen
authors: Angelika
authors: A
authors: Krumbein
authors: Christian
authors: C
authors: Ulrichs
authors: Marc
authors: M
authors: Lohse
authors: Rita
authors: R
authors: Zrenner
mesh_terms: D000818:Animals; D001042:Aphids / Q000502:physiology; D001937:Brassica / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism / Q000528:radiation effects*; D002080:Butterflies / Q000502:physiology; D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D017343:Genes, Plant / Q000235:genetics; D018525:Germination / Q000528:radiation effects*; D005961:Glucosinolates / Q000378:metabolism; D060434:Herbivory / Q000528:radiation effects; D055442:Metabolome / Q000528:radiation effects*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects*; D013312:Stress, Physiological / Q000528:radiation effects*; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D005419:Flavonoids; D005961:Glucosinolates; D012333:RNA, Messenger; D002734:Chlorophyll; D002338:Carotenoids