Strains, plasmids and primers used in this study.

aUnderline indicates the recognition sites by endonuclease. bItalic indicates the annealing sites with downstram/upstream primers.a. 下划线标注代表核酸内切酶（endonuclease）的识别位点；b. 斜体标注代表与下游/上游引物的退火结合位点。