Controlling self-incompatibility by CO2 gas treatment in Brassica campestris: Structural alteration of papillae cell and differential gene expressionby increased CO2 gas

Self-imcompatibility is a controlling genetic mechanism to prevent self-pol lination for Chinese cabbage (Brassica campestris), one of the major vegeta ble crops in Korea, To maintain inbred lines of the crop plant, a method in that high CO2 gas is treated to the pistils to overcome the self-incompati bility and thereby self-pollens can successfully make germination and ferti lization has been widely used in seed companies, Despite the common utiliza tion of this method, any molecular and cellular studies on how the self-inc ompatibility is removed from the Chinese cabbage plant have not been done. In this study, we show that the increased CO2 gas causes a structural alter ation of the papillae cell and thereby the self-incompatibility is removed from the Chinese cabbage plant, allowing the self-pollens to germinate and penetrate the papillae cell, Also, gene expression in the pistil treated wi th CO2 gas was studied by DD/RT-PCR and reverse northern hybridization expe riments. The results suggest that the failure in self-incompatible reaction resulted not only from the structural alteration of the papillae cell but also from change in the pistil component production that is either positive ly or negatively regulated by the environmental stimulation.