對日本慢生根瘤菌USDA110進行Tn5轉座子誘變，產生缺陷突變體。篩選根瘤菌中硝酸還原酶活性降低的菌株，通過實驗發現硝酸還原活性降低后固氮能力與對硝酸鹽的耐性提升。

參考文獻：María Camacho, Araceliburgos R d C ,ManuelA. Chamber-Pérez.Nitrogen fixation in transposon mutants from Bradyrhizobium japonicum USDA 110 impaired in nitrate reductase.[J].Journal of Plant Physiology, 2003, 160(4):377-386.