Lohar Dasharath Prasad, Bird David McK
Center for the Biology of Nematode Parasitism, Box 7253, North Carolina State University, Raleigh, NC 27695-7253, U.S.A.
Plant Cell Physiol. 2003 Nov;44(11):1176-84. doi: 10.1093/pcp/pcg146.
Sedentary plant-parasitic nematodes engage in complex interactions, and induce specialized feeding structures by redirecting plant developmental pathways, and parallels have been observed with rhizobial nodule development on legumes. A model legume would greatly facilitate a better understanding of the differences between parasitic (nematode) and mutualistic (rhizobia and mycorrhizae) symbioses, and we have developed Lotus japonicus as such a model. Conditions for efficient parasitism by root-knot nematode (Meloidogyne spp.) of the widely used Lotus "Gifu" ecotype were established. Features of Lotus biology, such as thin and translucent roots, proved ideal for monitoring the progress of nematode infection both on live specimens and post-staining. We examined L. japonicus mutants with nodulation phenotypes. One, har1, which is a hypernodulated mutant defective in a CLAVATA1-like receptor kinase gene, was found to be hyperinfected by M. incognita. However, another hypernodulated Lotus mutant exhibited the same level of M. incognita infection as wild-type plants. We also established conditions for infection of Lotus by soybean cyst nematode (Heterodera glycines). In contrast to the response to root-knot nematode, the Gifu ecotype is resistant to H. glycines, and elicits a hypersensitive response. This pattern of resistance recapitulates that seen on nematode-resistant soybean plants. We conclude that L. japonicus is a powerful model legume for studying compatible and incompatible plant-nematode interactions.
sedentary植物寄生线虫参与复杂的相互作用，通过重定向植物发育途径诱导形成特化取食结构，并且在豆科植物根瘤菌根瘤发育过程中也观察到了类似现象。一种模式豆科植物将极大地有助于更好地理解寄生（线虫）和互利共生（根瘤菌和菌根）共生之间的差异，我们已经培育出了日本百脉根作为这样一种模式植物。建立了广泛使用的百脉根“岐阜”生态型被根结线虫（Meloidogyne spp.）有效寄生的条件。百脉根生物学特性，如细且半透明的根，被证明对于在活体标本和染色后监测线虫感染进程非常理想。我们研究了具有结瘤表型的日本百脉根突变体。其中一个突变体har1，是一个在类CLAVATA1受体激酶基因中存在缺陷的超结瘤突变体，被南方根结线虫过度感染。然而，另一个超结瘤的百脉根突变体对南方根结线虫的感染水平与野生型植物相同。我们还建立了大豆胞囊线虫（Heterodera glycines）感染百脉根的条件。与对根结线虫的反应不同，岐阜生态型对大豆胞囊线虫具有抗性，并引发超敏反应。这种抗性模式与抗线虫大豆植株上观察到的一致。我们得出结论，日本百脉根是研究植物与线虫兼容和不兼容相互作用的有力模式豆科植物。
