Improving The Resistance Of Chinese Cabbage To Drought Stress By Genetic Engineering

Chinese cabbage (Brassica campestris L. ssp. pekinensis) is a popular vegetable in China. Aridity, a common form of abiotic stress, represents a strong limitation to agricultural production countrywide such as in Shanxi Province. The relative growth rate and development of Chinese cabbage are often inhibited in drought environment induced by unreasonable fertilization and irrigation.Hydrogen sulfide (H2S), which has recently been recognized as the third gasotransmitter for multiple signaling events in plants, can respond to drought, salinity, heavy metals and other abiotic stress and biotic stress.The LCD (L-cysteine desulfhydrase) gene, which encodes a protein degradating cysteine to generate H2S in Arabidopsis thaliana, was transformed into Chinese cabbage in our study. On the basis of establishment high frequency regeneration system of Chinese cabbage, we obtained transgenic plants which were transformed by Agrobactrium mediated method. This study enriched breeding materials of the Chinese cabbage with drought tolerance and provides new ideas to improve the vegetable production in Shanxi Province.The details were as follows:1.Establish regeneration system of Chinese cabbage: Gaokangyuqing, a Chinese cabbage breed, widely cultivated in Shanxi was used as materials and cotyledon with petioles as explants. We studied the effects of Agar concentration, pH value, AgNO3, NAA and6-BA on regeneration of Chinese cabbage in vitro. The results showed that the highest regeneration rate was79.43%in the MS medium containing2mg/L6-BA+0.3mg/L NAA+3.0mg/L AgNO3.2.Optimize the transformation system of Chinese cabbage: cotyledons with petioles were used as explants, and the culture conditions of transformed plants mediated by Agrobacterium tumefaciens were optimized. The results showed that, optimum organization culture medium for Gaokangyuqing was:MS+2.0mg/L6-BA+0.3mg/L NAA+3.0mg/L AgNO3+7.5mg/L Kan+50mg/L Amp. The optimum time period of pre-culturing is2d on the darkness, and the highest frequency is29.6%when explants are immersed in bacterium concentration with OD6oo0.2about3minutes. Resistant plants analysised by molecule method show that the AtLCD gene has been integrated into the genome of Chinese cabbage successfully and the AtLCD is expressed normally in the transgenic plants.