Characterization of a plant lamin-like protein in liverwort. Marchantia polymorpha strain:Tak-1

The nuclear lamina (NL) is a complex network of nuclear lamins and lamin-associated nuclear membrane proteins, which scaffold the nucleus to maintain structural integrity. In animals, type V intermediate filaments are the main constituents of nuclear lamina. Plant genomes do not encode any homologs of these intermediate filaments, yet plant nuclei contain lamina-like structures. In Arabidopsis thaliana, Nuclear Matrix Constituent proteins (NMCPs), which are required for maintaining structural integrity of the nucleus and specific perinuclear chromatin anchoring, function as nuclear lamins. Recent studies revealed additional roles of Arabidopsis NMCPs in modulating plant response to pathogen and abiotic stress. However, detailed analyses of Arabidopsis NMCP activities are difficult due to the presence of multiple homologs and their functional redundancy. In this study, we investigated the sole NMCP gene in the liverwort Marchantia polymorpha (MpNMCP). We found that MpNMCP proteins preferentially were localized to the nuclear periphery. Using CRISPR-Cas9 techniques, we generated MpNMCP loss-of-function mutant, which displayed reduced growth rate and curly thallus lobe. Transcriptome analyses indicated that MpNMCP was involved in regulating biotic and abiotic stress responses. Besides, a highly repetitive genomic region on the male sex chromosome, which was preferentially tethered at the nuclear periphery in wild-type thalli, decondensed and located in the nuclear interior. This perinuclear chromatin anchoring, however, was not directly controlled by MpNMCP. Altogether, our results unveiled that NMCP in plants have conserved functions in modulating stress responses.