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Bramsiepe J, Krabberød AK, Bjerkan KN, Alling RM, Johannessen IM, Hornslien KS, Miller JR, Brysting AK, Grini PE. Structural evidence for MADS-box type I family expansion seen in new assemblies of Arabidopsis arenosa and A. lyrata. Plant J 2023; 116:942-961. [PMID: 37517071 DOI: 10.1111/tpj.16401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 05/24/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023]
Abstract
Arabidopsis thaliana diverged from A. arenosa and A. lyrata at least 6 million years ago. The three species differ by genome-wide polymorphisms and morphological traits. The species are to a high degree reproductively isolated, but hybridization barriers are incomplete. A special type of hybridization barrier is based on 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 is 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 its 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 in the endosperm of A. arenosa and A. lyrata ssp. petraea, suggesting a genetic cause for the endosperm-based hybridization barrier between A. arenosa and A. lyrata ssp. petraea.
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Affiliation(s)
- Jonathan Bramsiepe
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
- CEES, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | - Anders K Krabberød
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | - Katrine N Bjerkan
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
- CEES, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | - Renate M Alling
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
- CEES, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | - Ida M Johannessen
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | - Karina S Hornslien
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | - Jason R Miller
- College of STEM, Shepherd University, Shepherdstown, West Virginia, 25443-5000, USA
| | - Anne K Brysting
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
- CEES, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
| | - Paul E Grini
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316, Oslo, Norway
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Bjerkan KN, Alling RM, Myking IV, Brysting AK, Grini PE. Genetic and environmental manipulation of Arabidopsis hybridization barriers uncovers antagonistic functions in endosperm cellularization. Front Plant Sci 2023; 14:1229060. [PMID: 37600172 PMCID: PMC10433385 DOI: 10.3389/fpls.2023.1229060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/12/2023] [Indexed: 08/22/2023]
Abstract
Speciation involves reproductive isolation, which can occur by hybridization barriers acting in the endosperm of the developing seed. The nuclear endosperm is a nutrient sink, accumulating sugars from surrounding tissues, and undergoes coordinated cellularization, switching to serve as a nutrient source for the developing embryo. Tight regulation of cellularization is therefore vital for seed and embryonic development. Here we show that hybrid seeds from crosses between Arabidopsis thaliana as maternal contributor and A. arenosa or A. lyrata as pollen donors result in an endosperm based post-zygotic hybridization barrier that gives rise to a reduced seed germination rate. Hybrid seeds display opposite endosperm cellularization phenotypes, with late cellularization in crosses with A. arenosa and early cellularization in crosses with A. lyrata. Stage specific endosperm reporters display temporally ectopic expression in developing hybrid endosperm, in accordance with the early and late cellularization phenotypes, confirming a disturbance of the source-sink endosperm phase change. We demonstrate that the hybrid barrier is under the influence of abiotic factors, and show that a temperature gradient leads to diametrically opposed cellularization phenotype responses in hybrid endosperm with A. arenosa or A. lyrata as pollen donors. Furthermore, different A. thaliana accession genotypes also enhance or diminish seed viability in the two hybrid cross-types, emphasizing that both genetic and environmental cues control the hybridization barrier. We have identified an A. thaliana MADS-BOX type I family single locus that is required for diametrically opposed cellularization phenotype responses in hybrid endosperm. Loss of AGAMOUS-LIKE 35 significantly affects the germination rate of hybrid seeds in opposite directions when transmitted through the A. thaliana endosperm, and is suggested to be a locus that promotes cellularization as part of an endosperm based mechanism involved in post-zygotic hybrid barriers. The role of temperature in hybrid speciation and the identification of distinct loci in control of hybrid failure have great potential to aid the introduction of advantageous traits in breeding research and to support models to predict hybrid admixture in a changing global climate.
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Affiliation(s)
- Katrine N. Bjerkan
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Renate M. Alling
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Ida V. Myking
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Anne K. Brysting
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Paul E. Grini
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
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