Impact of OTAbZIP on Ochratoxin A production, mycelium growth and pathogenicity of Aspergillus westerdijkiae under water activity stress

Figures & data

Table 1. Knockout PCR programme of the OTAbZIP gene in Aspergillus westerdijkiae fc-1.

Temperature (℃)		Time
	95	10 min
35X	95	30 s
	54	30 s
	72	1 min 30 s
	72	7 min
	4	∞

Figure 1. Correlation between the br-LZ domain of the OTAbZIP protein and MEME prediction in Aspergillus westerdijkiae fc-1 and other Aspergillus species.

Figure 2. (a) Identification of the hygromycin gene in the ∆OTAbZIP mutant Aspergillus westerdijkiae. (b) Strategy of gene replacement. Agarose gel electrophoresis showing PCR amplified products for wild type and ∆OTAbZIP mutant A. westerdijkiae fc-1. M: DL 5000 DNA Marker; 1–8: ∆OTAbZIP mutant A. westerdijkiae fc-1; 9: Wild-type A. westerdijkiae fc-1.

Figure 3. Mycelium growth of wild type and ∆OTAbZIP mutant Aspergillus westerdijkiae fc-1 strains in different a_w culture medium. WT: Wild-type A. westerdijkiae fc-1; ∆OTAbZIP: ∆OTAbZIP mutant A. westerdijkiae fc-1; a_w: Water activity. Different lowercase letters represent significant differences, p < 0.05.

Figure 4. Disease infection of wild type and ∆OTAbZIP mutant Aspergillus westerdijkiae fc-1 strains on pear fruit. WT: Wild-type A. westerdijkiae fc-1; ∆OTAbZIP: ∆OTAbZIP mutant A. westerdijkiae fc-1. Different lowercase letters represent significant differences, p < 0.05.

Figure 5. OTA production of the wild type and ∆OTAbZIP mutant Aspergillus westerdijkiae fc-1 strains under different a_w conditions. WT: Wild-type A. westerdijkiae fc-1; ∆OTAbZIP: ∆OTAbZIP mutant A. westerdijkiae fc-1; a_w: Water activity. Different lowercase letters represent significant differences, p < 0.05.

Figure 6. OTA biosynthesis gene (otaA, otaB, otaC, and otaD) and hog1 gene expression of the wild type (WT) and ∆OTAbZIP mutant Aspergillus westerdijkiae fc-1 strains under different aw treatment. Cont: Control group, 0 mL/L glycerine; a_w 0.96: 100 mL/L glycerine; a_w 0.91: 250 mL/L glycerine. Different lowercase letters represent significant differences, p < 0.05.