Abstract
In flowering plants, the female gametophyte controls pollen tube reception immediately before fertilization and regulates seed development immediately after fertilization, although the controlling mechanisms remain poorly understood. Previously, we showed that LORELEI (LRE), which encodes a putative glycosylphosphatidylinositol-anchored membrane protein, is critical for pollen tube reception by the female gametophyte before fertilization and the initiation of seed development after fertilization. Here, we show that LRE is expressed in the synergid, egg, and central cells of the female gametophyte and in the zygote and proliferating endosperm of the Arabidopsis (Arabidopsis thaliana) seed. Interestingly, LRE expression in the developing seeds was primarily from the matrigenic LRE allele, indicating that LRE expression is imprinted. However, LRE was biallelically expressed in 8-d-old seedlings, indicating that the patrigenic allele does not remain silenced throughout the sporophytic generation. Regulation of imprinted LRE expression is likely novel, as LRE was not expressed in pollen or pollen tubes of mutants defective for MET1, DDM1, RNA-dependent DNA methylation, or MSI-dependent histone methylation. Additionally, the patrigenic LRE allele inherited from these mutants was not expressed in seeds. Surprisingly, and contrary to the predictions of the parental conflict hypothesis, LRE promotes growth in seeds, as loss of the matrigenic but not the patrigenic LRE allele caused delayed initiation of seed development. Our results showed that LRE is a rare imprinted gene that functions immediately after double fertilization and supported the model that a passage through the female gametophyte establishes monoalleleic expression of LRE in seeds and controls early seed development.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 758-773 |
| Number of pages | 16 |
| Journal | Plant physiology |
| Volume | 175 |
| Issue number | 2 |
| DOIs | |
| State | Published - Oct 2017 |
Bibliographical note
Funding Information:1This work was supported by grants from the U.S. National Science Foundation to R.P. (IOS-1146090) and R.A.M. (MCB-1243608). 2 Current address: Department of Biology, Washington University in St. Louis, St. Louis, MO 63130. 3 Current address: Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455. 4 Current address: 315 Life Sciences Center, Columbia, MO 65211. 5 Address correspondence to rpalaniv@e-mail.arizona.edu. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Ravishankar Palanivelu (rpalaniv@e-mail.arizona.edu). Y.W., T.T., X.L., J.A.N., R.A.M., and R.P. designed the experiments; Y.W., T.T., X.L., and J.A.N. performed the experiments; R.P., Y.W., and R.A.M. wrote the article. [OPEN] Articles can be viewed without a subscription. www.plantphysiol.org/cgi/doi/10.1104/pp.17.00427
Publisher Copyright:
© 2017 American Society of Plant Biologists. All Rights Reserved.