A two-way molecular dialogue between embryo and endosperm is required for seed development

Area of Science:

• Plant biology
• Developmental biology
• Molecular signaling

Background:

• The plant embryonic cuticle is crucial for seedling survival, preventing water loss during germination.
• Cuticle formation is regulated by a signaling pathway involving ABNORMAL LEAF SHAPE1 (ALS1) and GASSHO (GSO) receptor-like kinases.

Purpose of the Study:

• To identify the ligand for GASSHO receptor-like kinases involved in embryonic cuticle formation.
• To elucidate the molecular dialogue between the embryo and endosperm in regulating cuticle integrity.

Main Methods:

• Identification of TWISTED SEED1 (TWS1) as a sulfated peptide ligand.
• Analysis of subtilase localization and function in the endosperm.
• Investigating the processing of TWS1 precursor and its effect on GASSHO signaling.

Main Results:

• TWISTED SEED1 (TWS1) is a sulfated peptide that functions as a GASSHO ligand.
• The subtilase ALS1, required for TWS1 activation, is produced in the endosperm, not the embryo.
• Endosperm-derived subtilase processes embryo-derived TWS1 precursor, triggering GASSHO-dependent cuticle reinforcement.

Conclusions:

• A bidirectional molecular dialogue between embryo and endosperm is essential for safeguarding embryonic cuticle integrity.
• This signaling pathway ensures proper cuticle development, critical for plant survival upon germination.