Sea urchin eggs contain a plastid-derived structure that contributes to their development

Area of Science:

• Marine Biology
• Developmental Biology
• Cell Biology

Background:

• Marine invertebrate development is often limited by nutritional availability.
• The transfer of non-metazoan organelles into the germline was previously considered improbable.

Purpose of the Study:

• To investigate the presence and function of plastid components in sea urchin eggs.
• To determine the impact of these components on offspring development and survival.

Main Methods:

• Microscopy and metabolite analysis to identify chromoplast components in Arbacia lixula eggs.
• DNA analysis to detect plastid DNA in eggs of multiple sea urchin species.
• Assessing the influence of plastid components on offspring traits.

Main Results:

• Chromoplast-derived carotenoid crystals and metabolites were found in sea urchin eggs.
• Plastid DNA, primarily from diatoms, was detected in 11 sea urchin species, correlating with egg size.
• These components influenced phytohormone and lipid metabolism, enhancing offspring development, plasticity, and survival.

Conclusions:

• Sea urchin eggs can incorporate and utilize plastid components, primarily from diatoms.
• This represents a novel form of maternal provisioning, enhancing offspring dispersal and survival.
• The findings challenge established concepts regarding intergenerational organelle transfer.