Root anatomy and development, the basis for nematode parasitism

Abstract

Plant parasitic nematodes appear to rely on very specific interactions with root cells to establish a feeding site. To understand these interactions in detail, it is of advantage to achieve a basic understanding of root development. Arabidopsis thaliana is a suitable plant to investigate root development genetically and molecularly, and it can act as a host plant for plant parasitic nematodes. The anatomy and the ontogeny of the Arabidopsis root can be described in considerable detail. Despite the rigorous lineage relationships in the root, laser ablation experiments demonstrate the presence of continuous information in the root meristem. This information guides cells to differentiate appropriately, according to position. A large spectrum of promoter traps that are specifically expressed in roots are examined in detail, and put into four categories. These expression patterns can be complex, and a relation between the tagged gene and cell type is not always obvious. As a complementary approach, genetic analysis, using specific mutants, is now beginning to unravel key genes that are involved in setting up the pattern of cell differentiation in the root. Combining promoter trap analyses with mutant analysis may create novel strategies for nematode control.