2.3 Construction of mutant and complementary strains
The gene spx, perR , aphC , sodA , sigB andrex was deleted by double crossover homologous recombination, respectively [35]. The detailed method to construct mutant strains were described in the supplementary materials. The plasmids were constructed for compensation of spx , perR and rex , respectively. Briefly, the gene spx , perR and rexwith their own promoters and terminators were amplified from the genomic DNA by PCR with the primers listed in Table S3 (Supplementary materials), cloned into T2(2)-ori joined by BamH I and XbaI restriction sites, then the constructed plasmids were used for transformation of Δspx , ΔperR and Δrex for construction of the complementary strain C-Δspx , C- ΔperR and C-Δrex respectively.