ACC脱氨酶对大豆快生根瘤菌及苜蓿中华根瘤菌共生固氮与竞争结瘤的影响
Effects of ACC deaminase on symbiotic nitrogen fixation and competitive nodulation in Sinorhizobium meliloti 1021 andSinorhizobium fredii HH103

利用大肠杆菌S17 1与根瘤菌进行两亲本接合转移，将苜蓿中华根瘤菌Sm1021中的ACC脱氨酶基因导入大豆快生根瘤菌HH103，在苜蓿中华根瘤菌Sm1021中过表达ACC脱氨酶基因，探讨ACC脱氨酶对根瘤菌共生固氮及竞争结瘤的影响。结果显示：接种过表达ACC脱氨酶的重组根瘤菌Sm1021，宿主植物地上部分鲜质量与结瘤数量有所增加；接种外源导入ACC脱氨酶的重组根瘤菌HH103，能够增加结瘤数，提高植物地上部分干质量且竞争结瘤能力增强。但是，接种2种重组根瘤菌后，宿主植物的根瘤鲜质量和根瘤固氮酶酶活性无明显变化。
An ACC deaminase gene from Sinorhizobium meliloti1021 was introduced into Sinorhizobium fredii HH103 and Sm1021 (providing extra copy of ACC deaminase gene) using the conjugation of Escherichia coli S17 1 and Rhizobium.These genetic engineering strains were inoculated to host plants to study the effect of ACC deaminase on symbiotic nitrogen fixation and competitive nodulation ability. The results showed that overexperssion of ACC deaminase in Sm1021 increased the nodule number and fresh weight in alfalfa. In soybean,inoculated with HH103 containing ACC deaminase also increased the nodule number,the dry weight and competitive nodulation ability. But the nodule fresh weight and nodule nitrogenase enzyme activity had no significant change both in alfalfa and soybean.