" Epidermal integrity in the Arabidopsis fruit receptacle.”.

Abstract :

Organ abscission is a pivotal process by which leaves, fruits, flowers, and seeds are shed in response to specific developmental programs or environmental cues. Abscission results in a newly exposed surface that had been thought to form a protective layer enriched in suberin and lignin. Our previous study unexpectedly revealed that residuum cells (RECs) in the abscission zone of Arabidopsis receptacles instead accumulate a protective cuticle layer after floral organ shedding, suggesting the hypothesis that epidermal cells are specified de novo during abscission. We establish why and how RECs transdifferentiate into epidermal cells following abscission using single-cell RNA-seq analysis. We reveal that REC trans-differentiation occurs through three distinct stages to acquire epidermal cell identity. We demonstrate that MYB74 is a key transcriptional regulator that guides REC trans-differentiation. Our results indicate that, contrary to wound-healing mechanisms that may restrict future growth at the site, epidermal trans-differentiation contributes to the subsequent growth of the fruit at the abscission site. Current progress on accidental cell fate changes and fruit development after abscission will be discussed.