A study on pathogenicity of bacteria carried by pine wood nematodes
A study on pathogenicity of bacteria carried by pine wood nematodes
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DOI：
10.1046/j.1439-0434.2003.00790.x
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发表时间：
2003-11-01
影响因子：
1.5
通讯作者：
Zhao, BG
中科院分区：
文献类型：
--
作者：
Han, ZM;Hong, YD;Zhao, BG
从黑松木质部和松材线虫表面分离到Njh、Njt和Njw三株细菌。这些细菌已分别被鉴定为荧光假单胞菌生物型I、荧光假单胞菌生物型II和泛菌属的一个种。为了确定致病性，愈伤组织和无菌黑松幼苗接种如下：仅接种无菌线虫（B. xylophilus和B. mucronatus）;仅细菌（菌株Njh、Njt、Njw中的每一种）和无菌线虫加细菌（B中的每一种）。xylophilus和B. mucronatus与Njh、Njt、Njw中的每一个组合）。结果表明，接种无菌B. xylophilus或B. mucronatus没有导致愈伤组织的布朗宁或无菌黑松幼苗的枯萎。而无菌线虫与Njh、Njt、Njw中的任一种共同接种则表现出一定程度的萎蔫或布朗宁症状。线虫加Njh或Njt的组合引起严重的症状，但线虫加Njw的组合症状较少。松材线虫携带的细菌在其致病性中起重要作用。此外，通过振荡在液体培养基中培养细菌。将滤液直接应用于愈伤组织，并测定每种细菌诱导布朗宁的能力。结果表明，Njh和Njt引起严重的布朗宁，而Njw不引起褐变。怀疑这是由于细菌培养液中的枯萎相关毒素所致。因此，推测该病害是由松材线虫和细菌共同侵染引起的，并可能存在细菌的毒害作用。
Three bacterial strains Njh, Njt and Njw, have been isolated with a high frequency from the xylem of the wilted black pine (Pinus thuntergii) and from the surface of the pine wood nematodes (Bursaphelenchus xylophilus). These bacteria have been identified as Pseudomonas fluorescens biotype I, P. fluorescens biotype II and a species of the genus Pantoea respectively. To determine pathogenicity, callus and aseptic black pine seedlings were inoculated as follows: aseptic nematodes only (each of B. xylophilus and B. mucronatus); bacterium only (each of bacterial strain Njh, Njt, Njw) and aseptic nematodes plus bacterium (each of B. xylophilus and B. mucronatus in combination with each of Njh, Njt, Njw). The results showed that inoculation with either aseptic B. xylophilus or B. mucronatus did not lead to browning of the callus or wilt of aseptic black pine seedlings. But those inoculated with aseptic nematodes plus any one of Njh, Njt, Njw showed some wilting or browning symptoms. The combination of nematodes plus either Njh or Njt caused severe symptoms but the combination of nematodes plus Njw had fewer symptoms. The bacteria carried by pine wood nematodes played an important role in pathogenicity. In addition, bacteria were cultured in liquid media through shaking. The filtered liquid was directly applied to the callus and the ability of each kind of bacterium to induce browning was determined. The results showed that Njh and Njt caused severe browning but Njw did not. It is suspected that this is due to wilt related toxins in the bacterial culture fluid. Therefore, it's suggested that the disease was caused by co-infection of both pine wood nematodes and bacteria and possible toxic effect of bacteria.