Effect Of Biocontrol To Pine Shoot Blight Disease By Burkholderia Cenocepacia Strain NSM-05

The study systematically researched the antibacterial effect of a Burkholeria cenocepacia strain NSM-05 to Sphaeropsis sapinea, including its colonization law, the field control effect, the safety and the antibacterial.substances. These results were the basis of the efficient biocontrol to the pine shoot blight disease. The main results were as follows:Plate confrontation test indicated that, of the 9 tested pine endophytic bacterial strains, just the NSM-05 strain has an evident antagonism activity to S.sapinea, the diameter of the bacteriostasis gap was 11.15mm, and the antibacterial activity could last longer time, Additionally, the fermentation broth had a stronger nematicidal activity to Bursaphelenehus xylophilus strain AMA3.The marked strain NSM-05 was successful colonizated in the pine inside of Pinus massoniana,P. thunbergii and P.elliottii by the either method of the spraying or the root pouring. The main colonization site was the stem, and the minor site was the root. There was no marked strain recovered from the needle.In greenhouse conditions, the strain NSM-05 had a significant role in promoting the growth of P.elliottii. After inoculated for 6 months, there was a significant difference in plant height and diameter of ground stem.The strain NSM-05 had an evident biocontrol effect to pine shoot blight disease in field. After treated 5days with the fermentation broth, S.sapinea was inoculated to the pine trees and the control effect was up to 93.76% with the method of spraying and was up to 87.49% with the method of root pouring. After inoculated S.sapinea 3 days, the fermentation was used to treat the pine trees, there was no control effector neither the method of spraying or root pouring.Safety testing of the plant model showed that the strain NSM-05 had no pathogenicity to the onion and alfalfa. It was supposed the strain was safe to the plant, human and animals.The study indicated that the antibacterial substances main presented in the metabolites and the bacterial cell had no antibacterial activity. The antibacterial substances were preliminary purified from the metabolites by the organic solvent extract and ammonium sulfate precipitation. The antibacterial substances eatracted by ethyl acetate had a stronger activity to S.sapinea and the diameter of the inhibition zone was 36.85mm. The antibacterial substances extract by the ammonium sulfate was weaker than which extract by the ethyl acetate and the diameter of the inhibition zone was 19.03mm.