CRWN nuclear lamina components maintain the H3K27me3 landscape and promote successful reproduction in Arabidopsis

The nuclear lamina, a crucial sub-nuclear protein matrix, maintains nuclear structure and genomic function. Our study centers on the Arabidopsis lamina component CROWDED NUCLEIs (CRWNs), unveiling their extensive role in the development of the reproductive system with a specific focus on the endosperm, which is pivotal in seed development. We showed that quadruple crwn null gametophytes exhibit limited viability, and crwn1 crwn2 (crwn1/2) mutations lead to defective seeds often having enlarged chalazal cysts and variable timing of endosperm cellularization. crwn1/2 endosperm also exhibit perturbations of level of tri-methylation of lysin 27 on histone H3 (H3K27me3) and transcriptomics. In addition, we found that PHERES1 (PHE1) targets and defense-related genes are mis-regulated in crwn1/2 endosperm, showing that both development and stress responses are affected by CRWNs simultaneously. The data also suggest that CRWNs affect various aspects of physiology of both vegetative and reproductive tissues but there are tissue-specific roles. To assess effect of loss of plant nuclear lamina protein CRWN1 and CRWN2 in endosperm, H3K27me3 CUT&RUN libraries for WT and crwn1/2 mutants in both endosperm (6C nuclei) and leaf tissues (combining 2,4,8,16C nuclei) were sequenced. mRNA-seq libraries were also sequenced for WT and crwn1/2 mutants in endosperm (6C nuclei). mRNA-seq libraries for leaves are available as 'SRA BioProject ID PRJNA485018'.