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Polyspermy produces tri-parental seeds in maize


Grossniklaus, Ueli (2017). Polyspermy produces tri-parental seeds in maize. Current Biology, 27(24):1300-1302.

Abstract

In flowering plants, two pairs of gametes participate in double fertilization. One of the two sperm delivered by the pollen tube (PT) fuses with the egg cell to form the zygote, whereas the second unites with the central cell to produce the endosperm [1]. Most animal species prevent polyspermy through a transient, fast block established by the depolarization of the egg membrane within milliseconds after encountering the first sperm, followed by a slow block generated through enzymatic changes in the extracellular matrix surrounding the egg [2]. Although in vitro fertilization experiments suggest that the maize zygote starts cell wall deposition within 30 seconds after fusion with a sperm [3], thereby preventing further fertilization events, it is unknown whether plant gametes prevent polyspermy by a fast block. Here, using a genetic approach, the absence of a fast block preventing polyspermy in the maize central cell is demonstrated. A putative polyspermy event involving the egg indicates the existence of tri-parental individuals, which may provide an alternative route to polyploidy, distinct from the one involving unreduced gametes.

Abstract

In flowering plants, two pairs of gametes participate in double fertilization. One of the two sperm delivered by the pollen tube (PT) fuses with the egg cell to form the zygote, whereas the second unites with the central cell to produce the endosperm [1]. Most animal species prevent polyspermy through a transient, fast block established by the depolarization of the egg membrane within milliseconds after encountering the first sperm, followed by a slow block generated through enzymatic changes in the extracellular matrix surrounding the egg [2]. Although in vitro fertilization experiments suggest that the maize zygote starts cell wall deposition within 30 seconds after fusion with a sperm [3], thereby preventing further fertilization events, it is unknown whether plant gametes prevent polyspermy by a fast block. Here, using a genetic approach, the absence of a fast block preventing polyspermy in the maize central cell is demonstrated. A putative polyspermy event involving the egg indicates the existence of tri-parental individuals, which may provide an alternative route to polyploidy, distinct from the one involving unreduced gametes.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Plant and Microbial Biology
07 Faculty of Science > Zurich-Basel Plant Science Center
Dewey Decimal Classification:580 Plants (Botany)
Language:English
Date:2017
Deposited On:10 Jan 2018 15:03
Last Modified:10 Jan 2018 15:07
Publisher:Cell Press (Elsevier)
ISSN:0960-9822
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1016/j.cub.2017.10.059
PubMed ID:29257958

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