Abstract
During the embryo maturation phase in Arabidopsis, cell division is arrested around 8 DAP. The fus3 mutants have been shown to fail to undergo such arrest. However, little is known about the molecular mechanisms underlying this process. We have been analyzing the downstream events regulated by FUS3 using transgenic plants, in which ectopic expression of FUS3 was induced artificially by estrogen. Ectopic expression of FUS3 during early seedling development resulted in the reduction of cell division activity and caused auxin-insensitivity. These results indicate that FUS3 negativelly regulates auxin-signal transduction, whereby cell division may be arrested during embryo maturation. We screened a mutagenized population of above transgenic plants for novel mutants defective in the FUS3-imposed growth arrest in seedling and isolated several lines that are impaired in embryonic growth arrest. Presentlly, we are investigating of alterations in auxin-signalling in the isolated mutants during the embryonic growth arrest phase.
