Arabidopsis NOTCHLESS plays an important role in root and embryo development.

Ribosome biogenesis is a fundamental process in eukaryotic cells. NOTCHLESS (NLE) is involved in 60S ribosome biogenesis in yeast, but its role in Arabidopsis () remains exclusive. Here, we found that Arabidopsis () is highly conservative in phylogeny, which encoding a WD40-repeat protein. is expressed in actively dividing tissues. AtNLE-GFP is localized in the nucleus. AtNLE physically interacts with the MIDAS domain of AtMDN1, a protein involved in the biogenesis of the 60S ribosomal subunit in Arabidopsis. The underexpressing mutant shows short roots and reduced cell number in the root meristem. In addition, the null mutant is embryo lethal, and defective embryos are arrested at the early globular stage. This work suggests that AtNLE interacts with AtMDN1, and AtNLE functions in root and embryo development.