Study On The Resistance Induced By Agricultural Antibiotics Such As Shenzinomycin Against Plant Gray Mold

The research on the mechanism of agricultural antibiotics to prevent and control plant diseases has always focused on killing the pathogens.With the rapid development of research in field of plant immunity and induced disease resistance in recent years,the effects of agricultural antibiotics on plant themselves and the research on inducing effect has attracted more and more attention.It will further explore the control mechanism of agricultural antibiotics,which is of great significance to its effective and efficient use in plant protection.Under the greenhouse conditions,by spraying on tobacco plants and inoculating plant gray mold on the leaves in vitro,the inducting effect of seven commonly used agricultural antibiotics,such as shenzinomycin,wuyimycin,avermectin,polyoxin,jinggangmycin,kasugamycin,were tested for the inducement effect.The antibiotics with the better inducement effect were selected,and the optimal inducement time and optimal concentration were further screened.The Real-time fluorescent quantitative PCR technology was used to detect and analyze the expression of NPR1,CTR1,ETR1 in signal transduction pathway after treatments of the three selected agents,shenzinomycin,polyoxin,and kasugamycin under their most appropriate inducing conditions.Finally the induction effects of shenzinomycin,polyoxin,and kasugamycin on gray mold of different plants were tested as well.1.Under greenhouse conditions,after spraying the lower leaves of tobacco with antibiotics,the leaves of the system were inoculated with plant gray mold in vitro,and the seven agricultural antibiotics were used to detect the inducement effect,time concentration.The results showed that shenzinomycin with a concentration of 40 mg/L 4 d,polyoxin with a concentration of 40 mg/L 4 d,and kasugamycin with a concentration of 80 mg/L 3 d exhibited the best effect on inhibiting plant gray mold,and the lesion diameters were significantly lower than the positive control(pyraclostrobin).The antifungal rate of polyoxin weighed against the control with the values of(35.96±0.18)%,(24.86±0.15)%,and(1.12±0.20)%,which were(57.46±0.15)%,(35.32±0.17)%,(34.33±0.20)%respectively,while the rest of the agents only showed a short-term inducing effect.2.Through the detection of tobacco allergic necrosis reaction test,it was confirmed that 40 mg/L shenzinomycin,5 mg/L polyoxin,80 mg/L kasugamycin could cause tobacco allergic necrosis.3.Under indoor conditions,after spray treatment on the lower leaves of tobacco by the selected three agents shenzinomycin,polyoxin,and kasugamycin 24 h,48 h,72 h,96 h,120 h,144 h and 168 h,the processed leaves and system leaves were collected and subjected to real-time fluorescent quantitative PCR to detect the relative expression of signal transduction pathway related genes NPR1,CTR1,ETR1 in tobacco plants.The results showed that shenzinomycin,polyoxin,and kasugamycin could stimulate the expression of disease-resistant marker gene NPR1,and thus activate the SA and JA、ET signal transduction pathways;and could inhibit the negative regulator of CTR1 gene downstream of ethylene and ETR1 gene in the ethylene signal transduction pathway,thereby inducing tobacco plants to produce systemic disease resistance.4.The detached leaves of tobacco,eggplant,strawberry,tomato,pepper and cucumber were inoculated with plant gray mold in vitro.40 mg/L shenzinomycin,5 mg/L polyoxin,and 80 mg/L kasugamycin were detected at their optimal time for 4 days,4 days and 3 days respectively.The results showed that the size of the diseased spots on the leaves of plants treated with shenzinomycin,polyoxin and kasugamycin were significantly lower than those of the control,and the inhibition rates were 25.86%～55.56%,25.17%～45.41%,and 20.17%～51.26%,respectively.