Analysis of the Oxidative Stress-Related Transcriptome from Capsicum annuum L.

For the massive screening of the genes related to oxidative stress, a cDNA library was constructed from hot pepper (Capsicum annuum L. cv. Nockkwang) leaves treated with methyl viologen. From this library, 1,589 cDNA clones were sequenced from their 5' ends. The sequences were clustered into 1,252 unigenes comprised of 152 contigs and 1,100 singletons. Similarity search against NCBI protein database identified 1,005 ESTs (80.3%) as Known, 197 ESTs (15.7%) as Unknown, and 50 ESTs (3.99%) as No hit. In the ESTs, oxidative stress-related genes such as ascorbate peroxidase, catalase, and osmotin precursor were highly expressed. The cDNA microarray containing 1,252 unigenes was constructed and used to analyze their expression upon methyl viologen treatment. Analyses of the hybridization revealed that various stress-related genes such as peroxidase, tyrosine aminotransferase, and omega-6 fatty acid desaturase, were induced and some metabolism related genes such as aldolase and ketol-acid reductoisomerase, were repressed by methyl viologen treatment, respectively. The information from this study will be used for further study on the functional roles of oxidative stress-related genes and signaling network of oxidative stress in hot pepper.