The nuclear lamina is a reticular network of filaments that lie under the inner nuclear membrane in eukaryotic cells. I investigated the roles of the nuclear lamina in plant cells, which were previously implicated in control of nuclear morphology and genome organization. CROWDED NUCLEIs (CRWNs) are Arabidopsis thaliana homologs of plant nuclear lamina proteins NUCLEAR MATRIX CONSTITUENT PROTEINs (NMCPs). In this dissertation, I demonstrated that loss of CRWNs induces a wide range of gene expression changes and the spontaneous induction of immunity responses. At least two double mutants, crwn1 crwn2 and crwn1 crwn4, exhibit salicylic acid mediated (SA) defense responses and cell death lesion formation. I further discovered that short-day conditions can partially suppress dwarfism and cell death in crwn1 crwn2 mutants. I found that long-day conditions are necessary to produce reactive oxygen species (ROS), which contributes to cell death and dwarfism in crwn1 crwn2 mutants, indicating that CRWNs are necessary to regulate light-mediated ROS generation and cell death. Finally, I examined roles of NMCPs/CRWNs in Solanum lycopersicum cv. M82 to check if functional similarities of NMCPs/CRWNs are present among different species. The Richards group found that nmcp2 single mutants and nmcp1a nmcp1b double mutants are not recoverable, demonstrating that NMCPs are indispensable for viability of plants. In addition, pollen abortion was found in NMCP1A/nmcp1a-1; nmcp1b-1/nmcp1b-1 mutants, which raised the possibility of NMCPs roles in male fertility. Collectively, these studies shed light on the role of plant nuclear lamina in pathogen response and development.