Central-cell-produced attractants control fertilization recovery.

Area of Science:

• Plant reproduction
• Molecular biology
• Angiosperm fertilization

Background:

• Angiosperm fertilization involves double fertilization, with only two sperm cells delivered by a single pollen tube.
• Failure of this process can jeopardize seed production and plant survival.
• Unfertilized gamete-controlled extra pollen tube entry is an evolved mechanism to salvage fertilization.

Purpose of the Study:

• To elucidate the molecular mechanism behind unfertilized gamete-controlled extra pollen tube entry in Arabidopsis.
• To identify the signaling molecules involved in salvaging fertilization when the primary attraction fails.

Main Methods:

• Investigated peptide signaling in Arabidopsis ovules.
• Analyzed the role of secreted peptides in pollen tube attraction.
• Utilized genetic analysis to assess the function of identified peptides in fertilization recovery.

Main Results:

• The central cell secretes SALVAGER1 and SALVAGER2 peptides.
• These peptides attract additional pollen tubes directionally when synergid-dependent attraction fails or is compromised.
• Loss of SAL peptides significantly impairs the ovule's ability to recover fertilization.

Conclusions:

• Discovered a novel female gamete-attraction system mediated by SALVAGER peptides.
• This system acts as a crucial backup mechanism for reproductive assurance in plants.
• Identified a key molecular pathway that salvages seed production.