Effect of seed on ripening control components during avocado fruit development

Area of Science:

• Plant Physiology
• Fruit Ripening Biology
• Molecular Botany

Background:

• Avocado fruit ripening is a complex process influenced by various factors.
• The role of the seed in regulating fruit development and ripening remains incompletely understood.
• Cultivar Arad naturally produces both seeded and seedless avocados, offering a unique model for research.

Purpose of the Study:

• To investigate the inhibitory effect of avocado seeds on fruit ripening.
• To elucidate the molecular mechanisms by which seeds influence ethylene production and gene expression during ripening.
• To compare the ripening process between seeded and seedless avocados.

Main Methods:

• Comparative analysis of seeded and seedless avocados from cultivar Arad at different developmental stages.
• Measurement of ethylene production and carbon dioxide (CO₂) levels.
• Quantitative analysis of gene expression for ethylene response pathway components (PaETR, PaERS1, PaCTR1) and MADS-box genes (PaAG1, PaAGL9).

Main Results:

• Seedless avocados exhibited enhanced responses to exogenous ethylene and higher CO₂ production throughout development.
• An ethylene production peak was observed in seedless fruit at the fruitlet stage, but not in seeded fruit.
• While ethylene response pathway genes showed similar expression, MADS-box gene PaAGL9 was specifically induced in seedless fruit early in development.

Conclusions:

• Avocado seeds play a significant role in inhibiting the ripening process.
• The seed appears to regulate the induction of MADS-box genes (PaAGL9) involved in the climacteric response.
• These findings highlight the seed's crucial function in controlling normal avocado fruit ripening.