Dormancy-specific imprinting underlies maternal inheritance of seed dormancy in Arabidopsis thaliana.

Urszula Piskurewicz,Daichi Susaki,Tetsu Kinoshita,Christian Megies,Luis Lopez-Molina,Mayumi Iwasaki

doi:10.7554/elife.19573

Urszula Piskurewicz, Daichi Susaki + Show 4 more

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https://doi.org/10.7554/elife.19573

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Journal: eLife	Publication Date: Dec 28, 2016
Citations: 48	License type: CC BY 4.0

Affiliation: University of Geneva, Yokohama City University

Abstract

Mature seed dormancy is a vital plant trait that prevents germination out of season. In Arabidopsis, the trait can be maternally regulated but the underlying mechanisms sustaining this regulation, its general occurrence and its biological significance among accessions are poorly understood. Upon seed imbibition, the endosperm is essential to repress the germination of dormant seeds. Investigation of genomic imprinting in the mature seed endosperm led us to identify a novel set of imprinted genes that are expressed upon seed imbibition. Remarkably, programs of imprinted gene expression are adapted according to the dormancy status of the seed. We provide direct evidence that imprinted genes play a role in regulating germination processes and that preferential maternal allelic expression can implement maternal inheritance of seed dormancy levels.

Highlights

Mature seeds are the endpoint of embryogenesis and highly resistant structures
To assess whether seed dormancy levels are determined by parental inheritance in these accessions, we measured the dormancy levels of F1 hybrid seeds generated after reciprocally crossing Cape Verde Islands-0 (Cvi) and C24 plants
We found that CYSTEINE PROTEASE1 (CP1) expression is stringently regulated upon seed imbibition according to seed dormancy levels and cold temperatures during seed development (Figure 3 and Figure 2—source data 5)

Summary

Introduction

Mature seeds are the endpoint of embryogenesis and highly resistant structures. In angiosperms, seed development is initiated after a double-fertilization event, which produces the endosperm and the zygote. Arabidopsis mature seeds consist of a desiccated and highly resistant embryo surrounded by a single cell layer of endosperm and an external layer, the testa, consisting of dead integumentary maternal tissues. Seed germination is a developmental transition that transforms the embryo into a fragile seedling This process is tightly controlled (Nonogaki, 2014; Yan et al, 2014). Dormancy is a vital trait that prevents germination out of season while maintaining the embryo in a protected state within the dry seed. As they age, dry seeds lose dormancy, a process known as dry after-ripening, i.e. they acquire the capacity to germinate under favorable germination conditions.

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