NDR/LATS-family protein kinase genes are indispensable for embryogenesis in Arabidopsis

NDR/LATS-family protein kinases are conserved among eukaryotes. These protein kinases in yeast and animals phosphorylate specific targets and regulate the cell cycle. Arabidopsis thaliana has eight NDR/LATS-family protein kinase genes (NDR1-8), of which NDR2, NDR4, and NDR5 are involved in regulating pollen development. However, the functions of the other NDR/LATS-family protein kinase genes in plants are unclear. Here, we show that three putative phosphorylation sites of an Arabidopsis basic leucine zipper transcription factor, VIP1, correspond to NDR/LATS-family protein kinase phosphorylation motifs and that two of these three sites are phosphorylated by NDR2, NDR3, or NDR8 in vitro. Expression of NDR1-8 was detected in various tissues. An NDR4 NDR6 NDR7 NDR8 quadruple mutation caused embryonic lethality These results suggest that different NDR/LATS-family protein kinases in plants have distinct physiological roles.