Phytoparasitic nematodes parasitize many species of rooting plants to take up nutrients, thus causing severe growth defects in the host plants. During infection, root-knot nematodes induce the formation of a characteristic hyperplastic structure called a root-knot or gall on the roots of host plants. Although many previous studies addressed this abnormal morphogenesis, the underlying mechanisms remain uncharacterized. To analyze the plant-microorganism interaction at the molecular level, we established an in vitro infection assay system using the nematode Meloidogyne incognita and the model plant Arabidopsis thaliana. Time-course mRNA-seq analyses indicated the increased levels of procambium-associated genes in the galls, suggesting that vascular stem cells play important roles in the gall formation. Conversely, genes involved in the formation of secondary cell walls were decreased in galls. A neutral sugar analysis indicated that the level of xylan, which is one of the major secondary cell wall components, was dramatically reduced in the galls. These observations were consistent with the hypothesis of a decrease in the number of highly differentiated cells and an increase in the density of undifferentiated cells lead to gall formation. Our findings suggest that phytoparasitic nematodes modulate the developmental mechanisms of the host to modify various aspects of plant physiological processes and establish a feeding site.

中文翻译：

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根结线虫在拟南芥根的根结形成过程中调节细胞壁。

植物寄生线虫将许多生根植物寄生化以吸收养分，从而在宿主植物中造成严重的生长缺陷。在感染过程中，根结线虫会在宿主植物的根部诱导形成称为根结或胆汁的特征性增生结构。尽管许多先前的研究都针对这种异常形态发生，但其潜在机制仍未阐明。为了在分子水平上分析植物与微生物的相互作用，我们建立了使用线虫Meloidogyne incognita和模型植物拟南芥的体外感染测定系统。时程mRNA-seq分析表明胆汁中与procambium相关的基因水平增加，表明血管干细胞在胆汁形成中起重要作用。反过来，参与次级细胞壁形成的基因在胆囊中减少。中性糖分析表明，木secondary是次要细胞壁的主要成分之一，其胆汁中木聚糖的含量显着降低。这些观察结果与高分化细胞数量减少和未分化细胞密度增加导致胆形成的假设一致。我们的发现表明，植物寄生线虫可以调节宿主的发育机制，从而改变植物生理过程的各个方面并建立一个饲养场所。这些观察结果与高分化细胞数量减少和未分化细胞密度增加导致胆形成的假设一致。我们的发现表明，植物寄生线虫可以调节宿主的发育机制，从而改变植物生理过程的各个方面并建立一个饲养场所。这些观察结果与高分化细胞数量减少和未分化细胞密度增加导致胆形成的假设一致。我们的发现表明，植物寄生线虫可以调节宿主的发育机制，从而改变植物生理过程的各个方面并建立一个饲养场所。