Double fertilization, uniquely observed in plants, requires successful sperm cell delivery by the pollen tube to the female gametophyte, followed by migration, recognition and fusion of the two sperm cells with two female gametic cells. The female gametophyte not only regulates these steps but also controls the subsequent initiation of seed development. Previously, we reported that loss of LORELEI, which encodes a putative glycosylphosphatidylinositol (GPI)-anchored protein, in the female reproductive tissues causes a delay in initiation of seed development. From these studies, however, it was unclear if embryos derived from fertilization of lre-5 gametophytes continued to lag behind wild type during seed development. Additionally, it was not determined if the delay in initiation of seed development had any lingering effects during seed germination. Finally, it was not known if loss of LORELEI function affects seedling development given that LORELEI is expressed in eight-day-old seedlings. Here, we showed that despite a delay in initiation, lre-5/lre-5 embryos recover, becoming equivalent to the developing wild-type embryos beginning at 72 hours after pollination. Additionally, lre-5/lre-5 seed germination, and seedling and root development are indistinguishable from wild type indicating that loss of LORELEI is tolerated, at least under standard growth conditions, in vegetative tissues.
Bibliographical noteFunding Information:
We thank Dr. Gary Drews for DD45:GFP seeds; Dr. Ramin Yadegari for provid ing access to the fluorescent microscope (Fig. 1); Shea Monihan and Dr. Karen Schumaker for assistance with root growth experiments (Fig. 2). We thank Dr. Jennifer Mach for critical reading of the manuscript. This work was supported by a NSF grant to R.P. (IOS-0723421).
- Glycosylphosphatidylinositol (GPI)-anchored protein
- Primary and lateral root growth
- Seed germination
- Seedling development