The Histone Chaperone HIRA Is a Positive Regulator of Seed Germination

The Histone Chaperone HIRA Is a Positive Regulator of Seed Germination

Histone chaperones regulate the flow and dynamics of histone variants and ensure their assembly into nucleosomal structures, thereby contributing to the repertoire of histone variants in specialized cells or tissues. To date, not much is known on the distribution of histone variants and their modifi...

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Bibliographic Details
Main Authors: Elodie Layat, Marie Bourcy, Sylviane Cotterell, Julia Zdzieszyńska, Sophie Desset, Céline Duc, Christophe Tatout, Christophe Bailly, Aline V. Probst
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:International Journal of Molecular Sciences
Subjects:
seed dormancy and germination
chromatin
histone variants
histone chaperones
seed vigor
Online Access:https://www.mdpi.com/1422-0067/22/8/4031
Description
Summary:Histone chaperones regulate the flow and dynamics of histone variants and ensure their assembly into nucleosomal structures, thereby contributing to the repertoire of histone variants in specialized cells or tissues. To date, not much is known on the distribution of histone variants and their modifications in the dry seed embryo. Here, we bring evidence that genes encoding the replacement histone variant H3.3 are expressed in Arabidopsis dry seeds and that embryo chromatin is characterized by a low H3.1/H3.3 ratio. Loss of HISTONE REGULATOR A (HIRA), a histone chaperone responsible for H3.3 deposition, reduces cellular H3 levels and increases chromatin accessibility in dry seeds. These molecular differences are accompanied by increased seed dormancy in <i>hira-1</i> mutant seeds. The loss of HIRA negatively affects seed germination even in the absence of HISTONE MONOUBIQUITINATION 1 or TRANSCRIPTION ELONGATION FACTOR II S, known to be required for seed dormancy. Finally, <i>hira-1</i> mutant seeds show lower germination efficiency when aged under controlled deterioration conditions or when facing unfavorable environmental conditions such as high salinity. Altogether, our results reveal a dependency of dry seed chromatin organization on the replication-independent histone deposition pathway and show that HIRA contributes to modulating seed dormancy and vigor.
ISSN:1661-6596
1422-0067

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