FIG 9.

Extracellular cell wall-degrading enzymes (CWDEs) produced by D. zeae strains MS2 and JZL7. (A) CWDE activities of strains MS2 and JZL at different cell concentrations. Samples of 20 μL bacterial cells (OD₆₀₀ of 0.5, 1.0 and 1.5) were added to the assay plate wells (5 mm in diameter) and incubated at 28°C. Pel and Peh assay plates were treated with 1 M HCl after 14 h, respectively. Cel assay plate was stained with 0.1% Congo red for 15 min after 14 h and decolored twice with 1 M NaCl. Photos were taken of Prt assay plate after 24 h without any further treatment. (B) RT-PCR of CWDE genes of strains MS2 and JZL (OD₆₀₀ of 1.5). The reference gene infB (coding transfer initiation factor 2) was used to equilibrate the concentration of cDNA samples. The expression of genes was determined by measuring the signal intensity of the bands (under the x axis) using Image Lab software (Bio-Rad, USA). Experiments were repeated three times in triplicate, and the mean data above the bars indicate the signal intensity of RT-PCR bands.