蜡样芽孢杆菌NJSZ-13菌株防治松材线虫病研究

[目的]松材线虫病是一种由松材线虫对赤松、马尾松、黑松等易感树种寄生取食继而引起树种死亡的病害,其发病速度快、易传播,传统的物理、化学防治成本高,且化学防治对环境易造成不可逆的污染,目前还没有较好的防治方法.为寻找安全有效的生物防治方法,笔者探究蜡样芽孢杆菌在温室下对马尾松盆栽苗松材线虫病的防治效果.[方法]采用人工皮...

A study on the biocontrol of pine wilt disease by Bacillus cereus NJSZ-13

【Objective】The pine wilt disease caused by parasitic Bursaphelenchus xylophilus occurs in susceptible tree species such as Pinus densiflora, P. massoniana and P. thunbergii. There is no optimal control treatment available owing to the fast onset and spread of the disease, high costs of physical and chemical control methods, and environmental pollution issues. To determine safe and effective biological control methods, this study explored the prevention and control of the disease by Bacillus cereus NJSZ-13 using potted P. massoniana seedlings in a greenhouse. 【Method】Different number of Bursaphelenchus xylophilus AMA3 (2 000, 4 000 and 6 000) were inoculated on two-year-old P. massoniana seedlings to determine the critical value of symptoms of the pine wilt disease. Bacillus cereus NJSZ-13 is a nematocidal endophyte that was isolated from P. elliottii in Nanjing. To understand the effect of B. cereus NJSZ-13 on the pine wilt disease, the roots of two-year-old P. massoniana were inoculated with a 20 mL suspension of 4×10 ⁸ cfu/mL of B. cereus NJSZ-13 as the treatment and with sterile water and an agar medium as the control. Twenty milliliters of bacterial powder suspension of 4×10 ⁸,4×10⁷ and 2×10⁷ cfu/mL of B. cereus NJSZ-13 were applied by the root filling method. Two-year-old P. massoniana seedlings were treated under two conditions, namely root filling with powder suspension and application of bacterial powder. Bacillus cereus NJSZ-13 and B. xylophilus AMA3 were inoculated with the P. massoniana roots in different orders, namely together, before 7 d, and after 7 d, and the control group was set up. The bacterial concentration, inoculation method, and time were included in the evaluation of the biocontrol effect. 【Result】The critical point of B. xylophilus inoculation in P. massoniana was 4 000. The fermented culture and sterilized culture of B. cereus NJSZ-13 had no effect on the pine wilt disease development. The biocontrol effect of the B. cereus NJSZ-13 suspension on the pine wilt disease was 33%. At the same concentration, the preventive effect of B. cereus NJSZ-13 did not differ between the powder and bacterial suspensions. The biocontrol effect of B. cereus NJSZ-13 did not improve when the bacterial suspension concentration reached a certain level. The biocontrol effect of B. cereus NJSZ-13 was significantly higher than that of the control. The control effect of B. cereus NJSZ-13 powder application was the same as that of the root filling method. 【Conclusion】The critical point of B. xylophilus inoculation in two-year-old P. massoniana can effectively avoid the disadvantage of an excessive concentration of B. xylophilus inoculation, which can reduce the control effect. The B. cereus NJSZ-13 bacterial suspension and powder had control effects on the pine wilt disease. It is better to apply B. cereus NJSZ-13 when P. massoniana is still healthy and uninfected. The preventive effect of B. cereus NJSZ-13 can be achieved by smearing the bacteria on pine branches.