| Streptomyces ahygrosscopicus gongzhulingensis n.var.strain"769"is a soil bacterium which has strong anti-bacterial activity against many plant pathogenic fungi.The metabolite of the strain“769”is gongzhulingmycin,which is a biosynthetic mixture with more biocontrol effects on many plant diseases.It is safe to human and animals and friendly to the environment.Gongzhulingmycin may has a wide range application potential in agriculture.We surveied the seedling establishment,seedling quality,yeild and quality to clarify the change of rice growth after applying gongzhulingmycin.The regulation of gongzhulingmycin on rice disease resistance was explored by assessing the expression of four defense genes,including Os MAPK6,Os FLS2,Os WRKY71,Os WRKY53 and the changes of activities of SOD,CAT,PAL,PPO in the leaves of rice seedings,and the rhizosiphere soil enzymes such as sucrase,cellulase,phosphatase,urease during seeding stage.The control effects of gongzhulingmycin on rice bakanae disease,rice seeding blight,and rice blast were studied under the different methods of application such as seed soaking,soil mixing and spraying,which clarified the potential of control on rice disease and verified the regulation of disease resistance.It provides a theoretical basis for production practice.The main results in this study are as follows:(1)Gongzhulingmycin could promote establishment of rice seedlings.The concentration of 800 times dilution could increase the germination rate of seeds and the height of rice seedings in the rice seedling stage in laboratory simulation environment.In the productive experiment in rice seeding shed,.it could significantly promote plant height and increase fresh weight of rice seedlings when the strain"769"solid culture were added 5 g/m~2and 10 g/m~2.The plant height were rising 7.93%and15.62%respectively,and the fresh weight were rising 25.58%and 34.89%respectively.Gongzhulingmycin could also increase the yield of rice while controlling rice blast when we applicated it from the jointing stage to the rupturing stage of rice.The yield increased ranges from 0.71%to 2.57%.And the yield increased by 8.22%when rice seeds were soaked with gongzhulingmycin.In addition,it could also improve the appearance,taste and nutrition quality of rice.(2)The expression of defense genes such as Os MAPK6,Os FLS2,Os WRKY71and Os WRKY 53 was significantly up-regulated under the stress of low temperature induced by gongzhulingmycin in lab model.It was rising 129.02%,98.39%,496.76%,392.97%respectively,compared to the control.The expression of Os FLS2,Os WRKY71,Os MAPK6 was increased by 48.16%,38.57%,35.34%respectively,when the strain"769"solid culture was added 8g/m~2in the soil in breeding seeding in rice seeding shed.The activities of the four defense-related enzymes such as PAL,POD,PPO and SOD were increased,especially SOD and PPO were significantly rising 57.18%and 28.53%compared to the control.The activities of sucrase,cellulase,phosphatase,urease have also increased,especially sucrase and cellulase were rising 190.48%and 42.11%when the strain"769"solid culture was added 8g/m~2in the soil.In summary,it was significantly induced the disease resistance when the strain"769"solid culture was added 8g/m~2in the soil at the seedling stage in rice seeding shed.(3)The tolerance to rice bakanae disease,rice seeding blight,and rice blast of the seedings were evaluated by gongzhulingmycin.The control effects of gongzhulingmycin on rice bakanae disease could reach 65.50%?96.30%by soaking seeds.The control effects of gongzhulingmycin on rice seeding blight were more effective than chemical pesticide when the strain"769"solid culture were added 3?10 g/m~2in the soil before sowing seeds,and the addition of 8 g/m~2was up to 98.08%.The control effects of gongzhulingmycin on rice leaf blast were tested in greenhouses and the concentration of 200 times dilution was the most optimal treatment.The control effects on rice leaf blast was 74.49%?82.26%by spraying with 100 times dilution of gongzhulingmycin in field trials,and the control effects on rice panicle blast was 63.97%?78.49%. |
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