导入dctABD和 parCBA/DE基因提高大豆慢生根瘤菌固氮效率和稳定性的研究

Improvement of Nitrogen Fixation Efficiency and Plasmid Stability in Bradyrhizobium japonicum by the Introduction of dctABD and parCBA/DE Genes

以ｐＬＡＦＲ３为载体构建重组质粒ｐＨＮ２０７，携带有来自首苜蓿根瘤菌（Ｓｉｎｏｒｈｉｚｏｂｉｕｍｍｅｌｉｌｏｔｉ）的四碳二羧酸转移酶基因 ｄｃｔＡＢＤ、来自 ｐＴＲ１０２的ｐａｒＣＢＡ／ＤＥ基因和标记发光酶基因 ｌｕｘＡＢ。利用 ２亲本杂交法，将重组质粒 ｐＨＮ２０７导入大豆慢生根瘤菌（Ｂｒａｄｙｒｈｉｚｏｂｉｕｍｊａｐｏｎｉｃｕｍ）ＴＡ１１和ＣＢ１８０９，分别考察了转移接合子中外源重组质粒在人工培养条件和共生条件下的稳定性，结果表明ｐａｒ基因的引入明显提高ｐＬＡＦＲ３在ＴＡ１１和ＣＢ１８０９中的稳定性。ｄｃｔＡＢＤ基因可显著提高ＴＡ１１和ＣＢ１８０９在大豆黑龙３３、宁镇一号和渝豆一号上的共生固氮能力，使结瘤植物的地上部分干重（生物量）和总氮量等指标较对照组有显著提高。

A recombinant plasmid pHN207 containing C4-dicarboxylic acid transport genes (dctABD) from Sinorhizobium meliloti, parCBA/ DE genes from PTR102 and reporter genes luxAB from pDB30 was constructed by using pLAFR3 as the vector. The pHN207 was then introduced into the Bradyrhizobium japonicum TA11 and CB1809 by bi-parental mating. It was confirmed that parCBA / DE genes could increase the stability of pLAFR3 in the transconjugants under both free-living and symbiotic condition, The results of plant pot experiment indicated that the introduction of dctABD genes could significantly improve the symbiotic nitrogen fixation efficiency of TA11 and CB1809 with soybean varieties of Heilong 33, Ningzhen No. 1 and Yudou No. 1. Compared with the control, the shoot dry weight (biomass) and total nitrogen content of the plants tested were significantly increased.