高固氮基因工程大豆根瘤菌的研制及其增氮效应

Study on A High Nitrogen Fixation Engineering Strain of Bradyrhizobium japonicum and Its Effect in Nitrogen Fixation Enhancement

通过构建快生型大豆根瘤菌Ｂ５２的基因文库和三亲本杂交，将增效因子ＤＮＡ片段导入优良的慢生型大豆根瘤菌２２－１０中，获得携带来自快生菌增效因子ＤＮＡ片段的工程菌株ＨＮ３２，经盆栽和小区试验，证明基因工程菌株ＨＮ３２比出发菌株２２－１０平均增产６％，比对照平均增产１３．２％～１６．９％，相当于每公顷施７５～１５０ｋｇ尿素．１９９２～１９９５年，在广西推广应用基因工程大豆根瘤菌ＨＮ３２２．１６万ｈｍ２，每公顷平均增产１９％，投入产出比１：３０。增加经济效益１４０９．８万元。

A synergistic DNA fragment from a Rhizobium fredii strain B52 was cloned and transferred to Bradyrhizobium japonicum strain 22-10 by triparental mating, and an engineering strain HN32 which contains the synergistic DNA fragement of the strain B52 has been obtained. By pot plant experiment and field test, it was shown that the engineering strain HN32's productivity reached 106% of the original strain 22-10 and 113. 2% to 116. 9% of the control, and its nitrogen fixation capacity equaled to the application of 75 to 150 kg urea per hectare. From 1992 to 1995, the engineering strain HN32 has been used over 21 600hectares in Guangxi and the average yield was increased up to 19%. The ratio of input/output is 1: 30.