Background : Cudrania tricuspidata Bureau is a widely used medicinal perennial woody plant. Obtaining information about the genetic diversity of plant populations is highly important for conservation and germplasm utilization. In this study, we developed single nucleotide polymorphism (SNP) markers derived from chloroplast genomic sequences to identify distinct Korean-specific ecotypes of C. tricuspidata via amplification refractory mutation system (ARMS)-PCR analyses. We performed molecular authentication of twelve C. tricuspidata ecotypes from different regions using DNA sequences in the chloroplast TrnL-F intergenic region. Methods and Results : SNPs were identified based on the results of nucleotide sequence for the intergenic region of TrnL-TrnF gene (chloroplast). Molecular markers were designed for those SNPs with additional mutations on the second base from SNPs for amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). HRM pattern analyses were performed using the Mx3005P QPCR System (Agilent Technologies, CA, USA). Conclusion : We collected 12 individual lines of C. tricuspidata from various region in South Korea and China. Based on the nucleotide sequence in the trnL-trnF intergenic region of these lines, six SNPs and a deletion of 12 bps were identified and 12 individual lines were able to be grouped in one Korean ecotype and two different ecotypes of chinese lines, chinese line 1 and 2. The SNP markers developed in this study are useful for rapidly identifying these specific C. tricuspidata ecotypes collected from different regions.

The effect of salicylic acid(SA) on antioxidant system and protective mechanisms against UV-B induced oxidative stress was investigated in cucumber(Cucumis sativus L.) leaves. UV-B radiation and SA were applied separately or in combination to first leaves of cucumber seedlings, and dry matter accumulation, lipid peroxidation and activities of antioxidant enzymes were measured in both dose and time-dependant manner. UV-B exposure showed reduced levels of fresh weight and dry matter production, whereas SA treatment significantly increased them. SA noticeably recovered the UV-B induced inhibition of biomass production. UV-B stress also affected lipid peroxidation and antioxidant enzyme defense system. Malondialdehyde(MDA), a product of lipid peroxidation, was greatly increased under UV-B stress, showing a significant enhancement of a secondary metabolites, which may have antioxidative properties in cucumber leaves exposed to UV-B radiation. Combined application of UV-B and SA caused a moderate increase in lipid peroxidation. These results suggest that SA may mediate protection against oxidative stress. UV-B exposure significantly increased SOD, APX, and GR activity compared with untreated control plants. Those plants treated with 1.0 mM SA showed a similar pattern of changes in activities of antioxidant enzymes. SA-mediated induction of antioxidant enzyme activity may involve a protective accumulation of H2O2 against UV-B stress. Moreover, their activities were stimulated with a greater increase by UV-B+SA treatment. The UV-B+SA plants always presented higher values than UV-B and SA plants, considering the adverse effects of UV-B on the antioxidant cell system. ABA and JA, second messengers in signaling in response to stresses, showed similar mode of action in UV-B stress, supporting that they may be important in acquired stress tolerance. Based on these results, it can be suggested that SA may participates in the induction of protective mechanisms involved in tolerance to UV-B induced oxidative stress.