Study On The Control Of Tomato Yellow Leaf Curl Virus Disease By Harpin Protein

Tomato yellow leaf curl virus disease is a devastating disease,which has been widely spread in more than ten provinces and cities in China in the past 10 years.It is hard to control the virus vector whitefly,which causes the disease spread to the whole country rapidly.The disease causes slow growth of tomato,wrinkled and deformed leaves,shrinking growth points,and seriously affects the yield and quality of tomato.Harpin protein is a multifunctional protein of plant pathogenic bacteria,which has been developed and utilized as a new plant immunity inducer in recent years.It is green,safe,and efficient.In this study,the effect of harpin on tylcvd was studied.The main results are as follows:1.According to the results of Hpa1 and Hpa1_10-42 concentration screening tests,different concentrations of harpin can inhibit the relative expression of TYLCV encoded V1,Hpa1 has the best inhibitory effect on the virus at 25μg/ml,and Hpa1_10-42 has the most obvious inhibition effect on the virus at 50μg/ml.2.Hpa1 and Hpa1_10-42were treated three days before TYLCV inoculation.The results showed that:The content of H₂O₂ in Hpa1 was the lowest and kept stable within 30 days;the content of H₂O₂ in Hpa1_10-42 treatment began to decrease gradually after 7 days;the content of H₂O₂in clear water control was the highest in several treatments.POD and SOD activity of Hpa1treatment were very high,followed by Hpa1_10-42treatment,and the SOD activity of 5%amino oligosaccharide aqueous solution and water control treatment was almost 0.The relative expression of V1 in four treatments showed a trend of first increasing and then decreasing,Hpa1 treatment had the lowest V1 relative expression and the most obvious inhibition effect on the virus.The overall effect was Hpa1>Hpa1_10-42>5%aminooligosaccharide>water control.The relative expression of PR1 in hpa1 treatment increased rapidly on the third day of inoculation,and decreased to the level similar to other treatments on the 15th day.There was no significant difference in the relative expression of PR1 between Hpa1_10-42,5%aminooligosaccharide,and clear water.3.There are six treatments in the field,namely Hpa1,Hpa1_10-42,HrpF,HrpF_536-803,5%amino oligosaccharide water,and water control,which are sprayed once in the planting period,the initial flowering period and the young fruit period.The specific test results are as follows:The incidence rate of clear water spray blank control was 50%.The control effect of Hpa1>Hpa1_10-42>HrpF_536-803>HrpF>5%aminooligosaccharide was 55.17%,53.54%,50.64%,47.44%,40.38%respectively.HrpF_536-803 and 5%aminooligosaccharide treatment were higher,24.04 cm,and 24.76 cm higher than that of water treatment respectively.The chlorophyll content of the six treatments began to decline after the young fruit stage,but the chlorophyll content of Hpa1 treatment decreased slowly,and the chlorophyll content of HrpF_536-803 treatment was higher in the initial flower stage and young fruit stage,and the fastest decline was after the young fruit stage.The soluble sugar content of HrpF and HrpF_536-803 treatment was the highest in the young fruit stage,while that of Hpa1_10-42treatment was the lowest in three stages.The soluble protein content of the six treatments also increased first and then decreased,the overall difference was small.HrpF_536-803treatment had the highest yield,about 8.4%increase in yield.The quality of tomato treated with hpa1 was better,the content of ascorbic acid and organic acid was higher,the color was uniform and the size was the same.The single fruit weight and lycopene content of HrpF_536-803 were the highest in several treatments.In conclusion,Hpa1 treatment had the best control effect,TYLCV inhibition and PR1relative expression in several treatments;HrpF_536-803treatment had the highest yield of tomato,and these two proteins had a good development and utilization prospect for the control of tylcvd and the improvement of tomato industry income.