Disease-resistant Analysis And Environmental Safety Evaluation Of The Transgenic Sugarcane Mediated With SrMV-P1

Sugarcane mosaic disease is one of serious diseases to sugarcane industry and influences the growth of sugarcane. Selection of resistant cultivars by genetic engineering was an assistant method in high-effective breeding of sugarcane. SrMV-P1 gene was transformed to sugarcane cv. Funong 95-1702 by particle bombardment in the Key Lab of Sugarcane Eco-Physiology& Genetic Improvement, Ministry of Agriculture in 2005, and 7 transgenic sugarcane clones were obtained. Using these transgenic sugarcanes as material, the resistance stability and agronomic performance of transgenic sugarcane were studied in the field. After resistance identifying repeatedly, the high-resistant transgenic line was chosen to study the physiological basis on the comparisons of photosynthesis and active oxygen metabolism between transgenic clones and nontransgenic control; and transgenic sugarcane environmental risk was assessed as well. The results showed as followed:Resistance to SrMV was improved significantly in the transgenic sugarcane mediated with SrMV-P1 gene, which resulted from the lower incidences of transgenic clones inoculated in artificial and/or natural infection. The SrMV incidence in transgenic clones ranged from 0% to 5%, while the incidence of the non-transgenic sugarcane Funong 95-1702 amounted to 30.81%-50%. According to the agronomic performance of transgenic sugarcane, the results indicated emergence rate of transgenic sugarcane was almost the same, tillering rate of transgenic sugarcane increased by 30%-44%, stalk length by 2.7%-8.9%, effective stalk by 8.2%-30.7%, cane yields of per hectare by 10.3%-43.6%, and the sugar content of per hectare increased by 28.2%-59% in transgenic sugarcane compared with the non-transgenic sugarcane.Compared with the non-transgenic controls, the net photosynthetic rate, stomatal conductance and transpiration rate of transgenic clones FGMSc05-2206 (TF64) were remarkably higher than those of non-transgeniccontrols (CK1) and P7(CK2).The SOD,POD activities in transgenic sugarcane clones greatly increased after inoculated with SrMV from the SrMV-infected Funong 95-1702 plants, which also resulted in the accumulation of H2O2 and oxidative cross-linking in the cell wall to prevent from the infection of virus.Environmental risk of SrMV-P1 transgenic sugarcane was primarily assessed through non-target organism investigation in the pot for two years. The total number of colony forming units(CFUs) of culturable bacteria and actinomycetes were increased in transgenic sugarcane rhizosphere soil, but the total number of CFUs of culturable fungi was not affected. Urease activities, sucrase activities and phosphatase activities were not influenced in the continuous 2-years transgenic sugarcane. Some effects on soil phosphomonoesterase were tested in the transgenic plants. These primary results indicated that transgenic sugarcane had some effects on soil bacteria and actinomycetes, but on effect on fungi; transgenic sugarcane had no disadvantage influence on soil fertility at the present time.