昆虫病原线虫共生细菌对南方根结线虫卵孵化的影响

Effect of Symbiotic Bacteria of Entomopathogenic Nematodes on Egg Hatching of Meloidogyne incognita

为探讨不同种(品系)昆虫病原线虫共生细菌的不同稀释倍数对南方根结线虫Meloidogyne incognita卵孵化的影响,采用培养皿法进行室内生测,定期调查根结线虫卵孵化情况。结果表明,4种(品系)昆虫病原线虫(斯氏属两个种和嗜菌异小杆两个品系)共生细菌的10×稀释液,6 d时Hb-NJ共生菌使M.incognita的卵孵化率最低,为8.6%,以TSY培养液为对照,其孵化率为29.1%,Hb-NJ共生菌对M.incognita卵孵化的抑制作用最强,相对抑制率为70.6%,其它3种昆虫病原线虫Hb-IGA、Sc-All和Sf-IGA共生细菌的孵化率为分别为24%、22.6%和25.2%,其相对抑制率是17.2%、22.3%和13.4%;8 d时线虫Hb-NJ、Hb-IGA和Sc-All共生菌的相对抑制率分别为67.1%、39.3%和41.7%,10 d时4种(品系)昆虫病原线虫共生菌对M.incognita的孵化率和抑制率均无显著性差异(p>0.05)。4种(品系)昆虫病原线虫共生菌的20×和50×稀释液对M.incognita卵孵化没有明显的抑制作用。基于以上结果,Hb-NJ的共生细菌可以通过抑制南方根结线虫的卵孵化导致线虫群体下降而达到防治线虫的目的,因此是一种潜在的生物杀线虫剂。

To explore the effect of different concentrations of symbiotic bacteria of entomopathogenic nematodes（ EPNs） on egg hatching of southern root-knot nematodes（ Meloidogyne incognita）,egg hatching rate was investigated at different interval time points by mixing with symbiotic bacteria in the Petri dishes in the laboratory. The results showed that the lowest egg hatching rate in 10 × dilution of symbiotic bacteria of Hb-NJ（ EPN） at 6 d was 8. 6% while it was 29. 1% compared with the control medium TSY. The strongest inhibition rate of 10 x dilution of symbiotic bacteria of Hb-NJ on M. incognita egg hatching was at 6 d,with 70. 6% of relative inhibition rate. The egg hatching rates in 10 × dilution of symbiotic bacteria of Hb-IGA,Sc-All and Sf-IGA at 6 d were 24%,22. 6%and 25. 2%,and their inhibition rates were 17. 2%,22. 3% and 13. 4%,respectively. At 8 d,the inhibition rates of symbiotic bacteria of Hb-NJ,Hb-IGA and Sc-All were 67. 1%,39. 3% and 41. 7%,respectively,and were significantly greater than that of Sf-IGA（ 11. 1%）. At 10 d,the egg hatching rates and the inhibition rates by the 10 x dilution of the four tested symbiotic bacteria had no significant difference. No obvious inhibition effect on M. incognita egg hatching was examined when using 20 x and 50 x dilutions of symbiotic bacteria at all tested days. Based on the results,the symbiotic bacteria of Hb-NJ might be a promising bio-agent to control root-knot nematodes through inhibiting M. incognita egg hatching and consequently result in decreased M. incognita infection.