Structural evidence for MADS-box type I family expansion seen in new assemblies of A. arenosa and A. lyrata

Bramsiepe, J.; Krabberod, A. K.; Bjerkan, K. N.; Alling, R. M.; Johannessen, I. M.; Hornslien, K. S.; Miller, J. R.; Brysting, A. K.; Grini, P. E.

doi:10.1101/2023.05.30.542816

bioRxiv · 10.1101/2023.05.30.542816

Structural evidence for MADS-box type I family expansion seen in new assemblies of A. arenosa and A. lyrata

Bramsiepe, J.·Krabberod, A. K.·Bjerkan, K. N.·Alling, R. M.·Johannessen, I. M.·Hornslien, K. S.·Miller, J. R.·Brysting, A. K.·Grini, P. E.

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Abstract

Arabidopsis thaliana diverged from A. arenosa and A. lyrata at least 6 million years ago and are identified by genome-wide polymorphisms or morphological traits. The species are to a high degree reproductively isolated, but hybridization barriers are incomplete. A special type of hybridization barrier is based in the triploid endosperm of the seed, where embryo lethality is caused by endosperm failure to support the developing embryo. The MADS-box type I family of transcription factors are specifically expressed in the endosperm and has been proposed to play a role in endosperm-based hybridization barriers. The gene family is well known for a high evolutionary duplication rate, as well as being regulated by genomic imprinting. Here we address MADS-box type I gene family evolution and the role of type I genes in the context of hybridization. Using two de-novo assembled and annotated chromosome-level genomes of A. arenosa and A. lyrata ssp. petraea we analyzed the MADS-box type I gene family in Arabidopsis to predict orthologs, copy number and structural genomic variation related to the type I loci. Our findings were compared to gene expression profiles sampled before and after the transition to endosperm cellularization in order to investigate the involvement of MADS-box type I loci in endosperm-based hybridization barriers. We observed substantial differences in type-I expression between A. arenosa and A. lyrata ssp. petraea in the endosperm, suggesting a genetic cause for the endosperm-based hybridization barrier in A. arenosa and A. lyrata ssp. petraea hybrid seeds.

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Bramsiepe, J., Krabberod, A. K., Bjerkan, K. N., Alling, R. M., Johannessen, I. M., Hornslien, K. S., Miller, J. R., Brysting, A. K., Grini, P. E.. 2023-05-31. Structural evidence for MADS-box type I family expansion seen in new assemblies of A. arenosa and A. lyrata. https://doi.org/10.1101/2023.05.30.542816

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