| In this thesis, I investigate the phenomena of DNA damage induced arrest in the Arabidopsis thaliana seedling and analyze the genes that may be involved in this arrest. In a separate vein, I also sought to confirm whether the Uvh1 gene product is involved in Agrobacterium tumefaciens mediated T-DNA transformation of plants.; The uvh1 mutant of Arabidopsis is a homolog of the Saccharomyces cerevisiae repair endonuclease RAD1 and is hypersensitive to gamma and UV radiation (Fidantsef et al., 2000; Liu et al., 2000). As a result of an arrest of meristem cells in G2, gamma irradiation of uvh1 plants triggers a cessation of seedling development. Mutants, termed suppressor of gamma (sog), were recovered in the uvh1 background that suppress this radiation induced arrest phenomena. Following gamma irradiation of uvh1 seedlings, a number of apoptotis-related and homeotic genes are increasingly expressed while many of the apoptotic genes are no longer up-regulated in the irradiated uvh1 sog1 double mutant seedlings. In the absence of any DNA damaging treatment, the uvh1 sog1 double mutant plants have decreased fertility, exhibit meiotic defects and have high levels of genomic instability. Finally, we demonstrate that the uvh1 gene is not required for T-DNA integration. |
