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인삼유래 CYP유전자의 지베렐린 생합성 유전자 조절을 통한 식물생장 조절과 제초제 저항성 기능
CYP Family Genes from Ginseng Functions on Plant Growth by Regulating Gibberellin Biosynthatase Genes and Herbicide Tolerance
Background : Cytochrome P450 enzymes belong to the superfamily of monooxygenases that are found in all living organisms with diversity in their reaction chemistry. These P450 enzymes are being used extensively by plants in their defense mechanism. Tetracyclic triterpenes reported as major ginsenoside constituents in Panax ginseng, formed by multiple hydroxylation of cytochrome P450. CYP P450 enzymes is effective in metabolising both natural and xenobiotic compounds. In this study, two ginseng CYP genes (PgCYP76C and PgCYP736A) were functionally characterized by overexpression in heterologous plant system.
Methods and Results : In Arabidopsis thaliana and Panax ginseng, planta transformation was generated by floral and cotyledon dipping method using Agrobacterium tumefaciens (C58C1) individually. Spatial and temporal patterns of gene expression were analyzed by qRT-PCR against abiotic and biotic stresses. Herbicide (chlorotoluron) tolerance was performed at seedling stage by in vitro assay to check ectopic expressions. PgCYP736A expression were more abundant in leaves compared to roots and stem of 2-years-old ginseng, where as PgCYP76C gene was found to be highly expressive in rhizome, roots and leaves. Differential expressions were observed in response to abiotic stresses of two ginseng CYP genes, both expressed higher in response to NaCl and SA (salysilic acid) in ginseng. Transgenic Arabidopsis plants overexpressing PgCYP76C gene showed small, rounded leaves and reduced height. This phenotype was found to be caused by down regulation of gibberellin biosynthesis-related genes. Another function revealed tolerance towards herbicides that belongs to phenyl urea.
Conclusion : This study indicates the functional roles of CYP genes in plant growth and stress responses. Studied genes also can be used as a tool to make plants herbicide tolerant. Further investigation might focus on it’s function over terpene biosynthesis and defence mechansim against (a)biotic stress.
