Molecular interaction between PHO2 and GIGANTEA reveals a new crosstalk between flowering time and Pi homeostasis in rice

Using a yeast to hybrid screen, it was found that PHO2, a key regulator of phosphate homeostasis, could interact with GIGANTEA, a key regulator of flowering time. In addition, mutant analysis revealed that both the pho2 and gi mutants shared similar phenotypes, both at the phosphate and flowering time levels. We used microarrays to analyse the effects of each mutation (pho2 or gi) on global gene expression, and assessed the proportion of genes similalry regulated in both mutants, in both shoots and roots. Wild-type (Nipponbare), pho2 and gi knock-out rice plants were grown to 21-days before harvesting root and shoot separately.