Early disruption of maternal-zygotic interaction and activation of defense-like responses in Arabidopsis interspecific incompatibility
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ABSTRACT: Hybridization of diverged taxa often result in lethality or sterility. We previously described natural variation for postzygotic incompatibility in the cross of diploid Arabidopsis thaliana to Arabidopsis arenosa. Hybrid seed death in this system has a complex genetic basis, involving many non-additive interactions. While activation of AGAMOUS-LIKE genes (AGL) and Athila elements have been detected 5-8 days after pollination (DAP), the molecular basis of death remains mysterious. To address this problem, we compared 3DAP transcriptomes in interspecific hybrids from two A. thaliana ecotypes, one compatible, the other incompatible. Relative to self crosses of the respective A. thaliana seed parent, hybrids displayed differential expression of key developmental regulators in both the endosperm and maternal seed coat as well as natural variation for stress response genes. Ribosomal protein genes and a photosynthetic cluster of genes were hyperactivated, presumably in response to growth signals. Suppressing endosperm growth factor IKU1 and defense response regulators such as NON-EXPRESSOR OF PATHOGENESIS RELATED1 (NPR1) improved hybrid seed survival. Therefore, in incompatible hybrids disruption of seed development most likely initiates in the endosperm, rapidly affecting embryo and seed coat. The activation of putative POLYCOMB REPRESSIVE COMPLEX (PRC) gene targets, together with a twenty-fold reduction in expression of the FERTILIZATION INDEPENDENT SEED 2 gene, indicates a PRC role. Examination of differential gene expression of incompatible A. thaliana eco. Col-0 X A. arenosa and compatible A. thaliana eco. C24 X A. arenosa hybrid seeds plus corresponding A. thaliana and A. arenosa control crosses.
ORGANISM(S): Arabidopsis thaliana
SUBMITTER: Isabelle Henry
PROVIDER: E-GEOD-42957 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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