Histone H3.3 deposition in seed is essential for the post-embryonic developmental competence in Arabidopsis

The acquisition of germination and post-embryonic developmental ability during seed maturation is vital for seed vigor, an important trait for plant propagation and crop production. How seed vigor is established in seeds is still poorly understood. Here, we report the crucial function of Arabidopsis histone variant H3.3 in endowing seeds with post-embryonic developmental potentials. H3.3 is not essential for seed formation, but loss of H3.3 results in severely impaired germination and post-embryonic development. H3.3 exhibits a seed-specific 5 gene end distribution and facilitates chromatin opening at regulatory regions in seeds. During germination, H3.3 is essential for proper gene transcriptional regulation. Moreover, H3.3 is constantly loaded at the 3 ' gene end, correlating with gene body DNA methylation and the restriction of chromatin accessibility and cryptic transcription at this region. Our results suggest a fundamental role of H3.3 in initiating chromatin accessibility at regulatory regions in seed and licensing the embryonic to post-embryonic transition.

Automated summary

This study reveals the crucial role of Arabidopsis histone variant H3.3 in endowing seeds with post-embryonic developmental potentials and regulating germination and post-embryonic development. H3.3 facilitates chromatin opening at regulatory regions, regulates gene transcriptional regulation during germination, and is associated with gene body DNA methylation and the restriction of chromatin accessibility and cryptic transcription at specific gene ends in seeds.