苜蓿乙硫氨酸抗性变异细胞系的筛选及特性分析

用经返地卫星搭载诱变处理豆科牧草紫花苜蓿（Ｍｅｄｉｃａｇｏ ｓａｔｉｖａ Ｌ．）干种子种植后长出的花序为外植体诱导愈伤组织，以Ｌ－乙硫氨酸为筛选剂，通过多步正筛选途径获得了苜蓿乙硫氨酸抗性细胞系ＭＥ＾ｒＢ．ＭＥ＾ｒＢ在脱离选择压９个月后，其对Ｌ－乙硫氨酸的抗性Ｉ５０（生长量半抑制时的Ｌ－乙硫氨酸浓度）比野生型高１４．２倍，表明抗性系抗笥表达稳定。抗性系还表现出对ＤＬ－甲硫氨酸的交叉抗性和对于冬氨酸

Selection of Ethionine-Resistant Variant Cell Line in Alfalfa (Medicago sativa L.) And study on Their Characteristics

Calluses were induced from inflorescence explants of alfalfa ( Medicago sativa L.) germinated from seeds treated with space conditions. A variant cell line resistant to 2 mmol/L L ethionine (ME rB) was isolated by means of multiple step selection from the calluses. The L ethionine resistance was stable since ME rB cell line grown on normal medium for 9 months retained high resistance to L ethionine and the I 50 (Concentration causing 50% growth inhibition) of ME rB was 14.2 times higher in comparison with that of the wildtype calluses. Simultaneously, ME rB exhibited cross resistance to DL methionine, as well as Threonine, Lysine, Isolecine, and Leucine separately or combinedly. Free amino acid analysis showed significant increase in the content of methionine. The obvious differences on peroxidase isoenzyme(POD) and Esterase isoenzyme(EST) electrophoresis patterns between ME rB and wildtype calluses indicated the possible existence of changed gene products in the ethionine resistant cell line.