Effect Of Biocontrol Strain Against Grape Crown Gall In The Pot

Grape crown gall is one of the most important bacterial diseases which cause the enormous economic loss.The disease is more frequent in northern China,and it is difficult to prevent.Chemical pesticide can produce resistance,threat human health and pollute the ecological environment.Consequently,due to the significant application prospects and development trends,biological control has become a brilliant method for preventing and controlling grape crown gall.Through field pot experiment,colonization and control efficiency of strains Ag-1,Ag-5,Ag-7,Ag-8.The results are as follows:1.Ag-1,Ag-5,Ag-7,Ag-8 had significant ability by colonization in the grape roots,among them,Ag-5 had the best colonization efficiency.By comparising the ability against the crown gall,the colonization ability of 4 biocontrol strains by pre-inoculating roots were stronger than which mixed with soil at 1 month after treatment(MAT).The colonization amount of Ag-1,Ag-5,Ag-7,Ag-8 on the root surface are all 104cfu/g(colony count per gram of tissue)at 5 MAT.Compared with 2 months(104cfu/g),the colonization amount of Ag-1,Ag-5,Ag-7,Ag-8 did not significant decrease.This indicates that Ag-1,Ag-5,Ag-7,Ag-8have strong colonization ability in grape roots.2.The efficiency of Ag-5 which controlled grape crown gall by pre-inoculation and irrigation with diluted LJ02 cells were 69.74% and 74.50%,respectively.The efficiency of Ag-8 which controlled grape crown gall by pre-inoculation and irrigation with diluted LJ02 cells were 73.63% and 78.68%,respectively.It indicated that the strains Ag-5 and Ag-8 had significant biocontrol efficiency to grape crown gall.Treatment of irrigating and pre-inoculating roots had significant efficiency in controlling grape crown gall.Ag-7 has a significant control efficiency to the R.radiobacter.3.The Ag-5 which labeled by GFP have significant colonize ability in tomato.the colonization amount of Ag-5 on the root reached the maximum(3.22×10~4cfu/g)at 45 days after irrigating root(DAI);the colonization amount decreased to 2.65×10~4cfu/g at 55 DAI and tended to be stable.The control efficiency of Ag-5-GFP proved that A.vitis had obvious pathogenesis at 15 days after inoculating.The efficiency of Ag-5-GFP which controlledA.vitis was 74.95% in tomato.It explained that the GFP gene can stably exist in strain Ag-5,and the biocontrol function of Ag-5-GFP can not be destroyed.The Ag-5 which labeled by GFP have significant control efficiency to A.vitis.