Researchers reveal a new epigenetic mechanism in creating seed vigor

Researchers reveal a new epigenetic mechanism in creating seed vigor

H3.3 establishes an appropriate chromatin regulatory landscape and endows seeds with post-embryonic development potential. Credit: IGDB

In plants, the production of highly vigorous seeds capable of germinating and establishing seedlings is vital to their propagation and is a valuable trait in crops. Plant seeds gain germination ability during the late seed maturation stage. However, it is not known how germination and post-embryonic developmental competence is established.

Epigenetic reprogramming is a highly temporal and spatial process essential for cell differentiation and evolutionary transition in animals and plants. Researchers led by Dr Jiang Danhua of the Institute of Genetics and Developmental Biology (IGDB) of the Chinese Academy of Sciences (CAS) have found that the incorporation of a histone H3.3 variant into chromatin is the key to the formation of germination and post-embryonic development ability in seeds.

In this study, they found that a complete loss of H3.3 in Arabidopsis thaliana strongly impairs seed germination and subsequent seedling development, even though it apparently does not affect seed formation.

Further analyzes revealed that H3.3 is highly expressed towards the end of seed maturation and its expression at this stage is essential and sufficient for seed germination.

They then demonstrated that a temporal deposition of H3.3 in the regulatory regions of the 5′ gene in mature seed establishes chromatin accessibility that foreshadows transcriptional competence for germination and post-embryonic development genes.

Intriguingly, although H3.3 is gradually removed from the 5′ gene ends during germination, the gene transcription competence established by H3.3 is maintained by sustained access of chromatin likely to transcription factors.

They also found that H3.3 is consistently loaded at the 3′ gene ends, correlating with gene body DNA methylation and restriction of chromatin accessibility and cryptic transcription in this region.

Their findings reveal an epigenetic mechanism that ‘unlocks’ post-embryonic developmental potentials in mature seeds. It will provide a basis for further investigations on seed vigor, a less studied field especially at the molecular level, but of fundamental importance for agriculture and the seed industry.

This work entitled “Histone H3.3 deposition in seed is essential for the post-embryonic developmental competence in Arabidopsis” was published in Nature communications on December 13th.

More information:
Ting Zhao et al, histone H3.3 deposition in seed is essential for post-embryonic developmental competence in Arabidopsis, Nature communications (2022). DOI: 10.1038/s41467-022-35509-6

Provided by the Chinese Academy of Sciences

Citation: Researchers reveal new epigenetic mechanism in creating seed vigor (2022, Dec 20) Retrieved Dec 20, 2022 from https://phys.org/news/2022-12-reveal-epigenetic-mechanism-seed-vigor. html

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