2株分泌型铁载体真菌对番茄青枯病的防效

为筛选对番茄青枯病防治效果好的天然产物，本文以分泌型铁载体产生菌云南木霉Trichoderma yunnanense 2-14F2和拟球孢白僵菌Beauveria pseudobassiana 2-8F2为材料，考察其铁载体活性物质对番茄青枯病的防效。采用CAS检测法及全波段紫外光吸收法判定铁载体化学结构类型及其活性。采用Sephadex-LH20凝胶划段法分离活性物质。采用平板扩散及96孔板倍半稀释法检测铁载体活性物质对青枯雷尔氏菌Ralstonia solanacearum的离体抑菌活性；采用盆栽法检测活性物质对番茄青枯病的防效。结果显示，菌株2-14F2和2-8F2产铁载体活性单位(SU)分别为62.02%和52.06%,铁载体化学结构类型均为异羟肟酸盐型(hydroxamates)。当铁载体活性物质浓度为0.15 mg/mL时，两菌株对青枯雷尔氏菌抑菌率分别为73.26%(2-14F2)和37.23%(2-8F2);对番茄青枯病的防治效果分别达到51.36%(2-14F2)与50.27%(2-8F2)。此外，当两菌株铁载体活性物质中含1 mol/L FeCl₃

Control effects of two siderophore-producing fungi against tomato bacterial wilt

In order to screen natural products with good control effect against tomato bacterial wilt, secretory siderophore-producing strains Trichoderma yunnanense 2-14F2 and Beauveria pseudobassiana 2-8F2 were selected to investigate the effect of its siderophore active substances on tomato bacterial wilt. The CAS detection and the full-band ultraviolet light absorption methods were used to determine the chemical structure type and activity of siderophores. Sephadex-LH20 gel segmentation method was used to separate the active substances. The antibacterial activity of siderophore active substance against Ralstonia solanacearum was investigated in vitro by plate diffusion and half dilution method in 96-well plate. The control effect of active substance on tomato bacterial wilt was investigated in vivo by using potting method. The results showed that the siderophore activity unit (SU) of 2-14F2 and 2-8F2 was 62.02% and 52.06%, respectively, and the siderophore chemical structure types were all hydroxamates. When the concentration of siderophore active substance was 0.15 mg/mL, the inhibitory rates of the two strains against R.solanacearum were 73.26% (2-14F2) and 37.23% (2-8F2), respectively, and the control effect on tomato bacterial wilt reached 51.36% (2-14F2) and 50.27% (2-8F2), respectively. In addition, after supplement with FeCl3 solution (final concentration 1 mol/L) to the siderophore active substance, the inhibitory rate and control effect were significantly reduced. This phenomenon indicated that the biological activities of the two strains were related to siderophores and environmental iron. These results provides a theoretical basis for the development and utilization of strains secreting siderophore for biological control in the field.