Relationship between Alternative Respiration and Sensitivity of Growth Rate in Botrytis cinerea Collected from Vegetable Greenhouses to Azoxystrobin

The relationship between alternative respiration and sensitivity to azoxystrobin during the stage of mycelial growth in B.cinerea population was analysed.The results showed that salicylhydroxamic acid (SHAM),a specific inhibitor of alternative oxidase,had different impact on growth rate of different isolates.Inhibition percentage of SHAM at a dose of 50 μg /mL to the tested 142 isolates collected from Zhejiang,Jiangsu and Shandong province ranged from -29.03% to 48.33%,with an average value of 10.49%.Meanwhile,SHAM expressed a notable synergistic interaction with azoxystrobin against B.cinerea.In the absence of SHAM,medium effective concentrations (EC50Q) inhibiting growth rate of the tested population by azoxystrobin ranged from 0.20 to 51.48 μg /mL,with an average value of 6.56 μg /mL. In the presence of 50 μg /mL SHAM, the EC50 ranged from 0.04 to 5.25 μg /mL,with an average value of 2.21 μg /mL. The factor value for the impact of alternative respiration on sensitivity to azoxystrobin ranged from 0.17 to 24.40,with an average value of 3.19.Moreover,some ' tolerant ’ isolates in the absence of SHAM were also sensitive to azoxystrobin when SHAM presented.