Sinha H, Pain A, Johnstone K
Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom.
J Bacteriol. 2000 Nov;182(22):6532-5. doi: 10.1128/JB.182.22.6532-6535.2000.
Switching between the pathogenic smooth (1116S) and nonpathogenic rough (1116R) forms of Pseudomonas tolaasii occurs due to the reversible duplication of a 661-bp element within the pheN locus. Disruption of the chromosomal recA locus of 1116S and 1116R produced strains 1116SrecA and 1116RrecA, respectively, which showed typical loss of UV resistance. Switching from the smooth to the rough form was virtually eliminated in the 1116SrecA strain, whereas the extent of switching from the rough to the smooth form was almost identical in 1116R and 1116RrecA. It is concluded that phenotypic switching from 1116S to 1116R is recA dependent whereas that from 1116R to 1116S is recA independent.
托拉氏假单胞菌的致病光滑型（1116S）和非致病粗糙型（1116R）之间的转换是由于pheN基因座内一个661碱基对元件的可逆重复。分别破坏1116S和1116R的染色体recA基因座产生了菌株1116SrecA和1116RrecA，它们表现出典型的紫外线抗性丧失。在1116SrecA菌株中，从光滑型到粗糙型的转换几乎被消除，而在1116R和1116RrecA中，从粗糙型到光滑型的转换程度几乎相同。得出的结论是，从1116S到1116R的表型转换依赖于recA，而从1116R到1116S的表型转换不依赖于recA。
