Optimization Of The Activity Of Protein Elicitor AMEP By Adding Adjuvant

In view of the problems of environmental pollution caused by traditional chemical control,it is particularly important to find green and pollution-free biological pesticides.AMEP protein is a new Protein Elicitor identified from Bacillus subtilis.This protein can induce systemic acquired resistance of plants and improve their resistance to external adverse environment.In order to save the cost of application,AMEP protein should be mixed with foliar fertilizer,which is the trend of drug fertilizer integration at this stage.In this study,allergic reaction was used as an index of protein activity to screen the adjuvant and determine the most suitable adjuvant composition;Then,taking soybean as the experimental variety,the treatment combinations of control,protein and protein + adjuvants were set up to verify the effect of adjuvant through pot experiment and field experiment.The specific research results are as follows:1.Take allergic reaction as the detection index,check the size of necrotic plaque at the protein injection site of leaves,and determine the effect of each adjuvant on AMEP protein activity.The results showed that the activity of AMEP protein was the best at low concentration of ferrous sulfate,urea,copper sulfate,zinc sulfate,manganese sulfate and sodium molybdate;Potassium dihydrogen phosphate inhibited protein activity and should not be added;The activity of AMEP protein was the best when boric acid was at medium concentration;The protein activity was the best when p H was 7-8;Then,the above adjuvants were mixed and gradient set,and it was found that the allergic reaction caused by 0.5 times the concentration of the mixed adjuvant was the best;Finally,it was determined that the adjuvant combination that AMEP protein should add was: urea 0.05 g/l,ferrous sulfate 0.06 g/l,copper sulfate 0.005 g/l,manganese sulfate 0.01 g/l,boric acid 0.2 g/l,zinc sulfate 0.05 g/l,sodium molybdate 0.005 g/l,and the p H was adjusted to 7-8.2.Pot experiment was conducted to verify the improvement of AMEP protein activity by adjuvants.Three treatment combinations of control,protein and protein + adjuvants were set to detect the related indexes of drought resistance of soybean.The results showed that during drought stress,the phenotypic indexes of plant height,stem diameter,plant fresh weight and plant dry weight of protein + adjuvants treatment increased by 5.45%,5.3%,2.80% and 2.81%respectively compared with protein treatment;The activities of ascorbic acid,cat and pod were increased by 12.7%,6.7% and 11.7%,respectively;In terms of membrane lipid peroxides,malondialdehyde content and electrolyte permeability decreased by 10.1% and 10.0%respectively,while root activity,superoxide anion production rate and hydrogen peroxide content increased by 4.2%,2.9% and 5.4% respectively;The content of soluble protein,soluble sugar and free proline increased by 12.2%,7.1% and 10.7% respectively;In terms of photosynthetic indicators,net photosynthetic rate,transpiration rate and stomatal conductance increased by1.4%,10.6% and 10% respectively,intercellular carbon dioxide concentration decreased by7.2%,fluorescence parameters such as original light energy conversion efficiency,actual photochemical quantum yield,photochemical quenching coefficient and non optical quenching coefficient increased by 3.8%,6.0%,2.7% and 1.8% respectively,and chlorophyll content increased by 3.5%.The above results show that the addition of adjuvant further improves the physiological indexes related to drought resistance of soybean,which proves that the adjuvant further improves the activity of AMEP protein.3.Field experiments were conducted to verify the improvement of AMEP protein activity by adjuvants.Three treatment combinations of control,protein and protein + adjuvants were set to detect the yield indexes of soybean,such as pod setting,grain number and yield per mu.The results showed that in the early flowering stage,the plant height,node number,stem diameter and flowering number of protein + adjuvants treatment were increased by 3.8%,4.7%,8.3% and7.3% compared with protein treatment;In the pod setting stage,the number and weight of pods increased by 6.1% and 15.1%;In the mature stage,the total grain weight and 100 grain weight increased by 0.8% and 3.9% respectively,and the number of shriveled pods decreased by 4.2%.At the yield level,the soybean yield of the control group was 172.1 kg / mu,that of the protein treatment group was 182.2 kg / mu,and that of the protein + adjuvants treatment group was189.34 kg / mu.The yield of the protein + adjuvants treatment was 3.91% higher than that of the protein treatment.The enhancement of AMEP protein activity by adjuvant was further verified.In conclusion,the optimized AMEP protein improved the phenotypic indexes of soybean seedlings,enhanced the antioxidant capacity and osmotic regulation capacity of soybean leaves,alleviated the damage of peroxidation to plants and enhanced the drought resistance under drought conditions.In the field experiment,100 grain weight,total pod number and pod weight were further increased,the number of shriveled pods was significantly reduced,and the yield of soybean was increased.This shows that the adjuvant can significantly improve the activity of AMEP protein,which can provide experience and guidance for the application of AMEP protein in agricultural production.