The complete genome sequences of a number of multicelluar organisms such as Arabidopsis, human and mouse have been known for a while. The functions of most genes identified by genome sequencing are still unknown. With the complete genome sequence known and knockout mutants for almost every gene available, Arabidopsis is becoming a very powerful platform for systematic analysis of gene functions. The lab is currently analyzing a large number of genes in Arabidopsis using systems biology approaches. We would like to identify functions of genes with important roles in innate immunity and other biological processes shared between Arabidoposis and human. What they learned in Arabidopsis may help us better understand these processes in human.