Overexpression of ginseng cytochrome P450 alters plant growth and confers phenylurea herbicide tolerance in Arabidopsis.

BACKGROUND

Cytochrome P450 enzymes catalyze a wide range of reactions in plant metabolism. Besides their physiological functions on primary and secondary metabolites, P450s are also involved in herbicide detoxification via hydroxylation or dealkylation. Ginseng as a perennial plant offers more sustainable solutions to herbicide resistance.

METHODS

Tissue-specific gene expression and differentially modulated transcripts were monitored by quantitative real-time polymerase chain reaction. As a tool to evaluate the function of , the 35S promoter was used to overexpress the gene in Arabidopsis. Protein localization was visualized using confocal microscopy by tagging the fluorescent protein. Tolerance to herbicides was analyzed by growing seeds and seedlings on Murashige and Skoog medium containing chlorotoluron.

RESULTS

The expression of was three-fold more in leaves compared with other tissues from two-year-old ginseng plants. Transcript levels were similarly upregulated by treatment with abscisic acid, hydrogen peroxide, and NaCl, the highest being with salicylic acid. Jasmonic acid treatment did not alter the mRNA levels of Transgenic lines displayed slightly reduced plant height and were able to tolerate the herbicide chlorotoluron. Reduced stem elongation might be correlated with increased expression of genes involved in bioconversion of gibberellin to inactive forms. PgCYP736A12 protein localized to the cytoplasm and nucleus.

CONCLUSION

does not respond to the well-known secondary metabolite elicitor jasmonic acid, which suggests that it may not function in ginsenoside biosynthesis. Heterologous overexpression of reveals that this gene is actually involved in herbicide metabolism.