Rhizotoxic ions inhibit root growth, resulting in reduced yield of various crop plants. It is thus
improvement of tolerance of roots to rhizotoxic ions, one of the most important targets in plant breeding, to
improve the productivity of crops in various soil types. Molecular breeding such as marker assisted selection and
transgenic breeding would be promising approaches in current plant breeding, while identification of critical
genes is needed to realize these approaches. In this chapter, we introduce recent progress of transcriptomics and
other -omics studies for complex response of plant roots to rhizotoxic ions, and those that for identifying critical
genes for tolerance to rhizotoxic ions.
