Construction and analysis of an intergeneric fusant able to degrade bensulfuron-methyl and butachlor

Abstract

Rhodococcus sp. BX2 degrades bensulfuron-methyl but not butachlor, and Acinetobacter sp. LYC-1 degrades butachlor but not bensulfuron-methyl. Functional strains were constructed through protoplast fusion of Rhodococcus sp. BX2 and Acinetobacter sp. LYC-1 to generate fusants with an improved ability to simultaneously degrade bensulfuron-methyl and butachlor. Initial identification and stability tests of the fusants were performed. Three fusants with eighth transfer on plates containing two antibiotics and two herbicides were obtained. F1 also grew well in an inorganic salt solution containing bensulfuron-methyl and butachlor. F1 was characterized by its parents' morphological and physio-biochemical features. F1 not only had bands in common with BX2 and LYC-1, but also had its own specific bands analyzed by Random Amplified Polymorphic DNA. The genetic similarity indices between F1 and BX2 and F1 and LYC-1 were 0.507 and 0.470, respectively. The percentages bensulfuron-methyl and butachlor degradation by F1 in an inorganic salt solution supplemented with 100 mg/L bensulfuron-methyl and 100 mg/L butachlor were 65.35 and 62.41 %, respectively, and the percentages in soil contaminated with 10 mg/kg bensulfuron-methyl and 10 mg/kg butachlor with an inoculum size of 5 % at 34 °C and at a pH of 7.5 after 35 days were 63.74 and 61.53 %, respectively. It was demonstrated that F1 could simultaneously degrade bensulfuron-methyl and butachlor.