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AS1 Transcription Factor in Arabidopsis Floral Organ Abscission Zone Shifts Lignin Deposition in an inverted V-Shape

Start Date

30-4-2025 11:30 AM

Document Type

Event

Description

Poster Presenter: Dikshya Niraula

Research Team: Dikshya Niraulaand and Sarah Liljegren

Abstract: Plants have a natural ability to shed organs like leaves, flowers and fruit at specific points during their life cycle. Flowers of the model plant, Arabidopsis thaliana, release their sepals, petals, and stamens after fertilization. Cell separation within specialized abscission zones allows detachment of these floral organs. Within the sepal abscission zone, lignification of a set of cells forms a structural brace that prevents the diffusion of cell wall degrading enzymes. Previous studies have shown that the ASYMMETRIC LEAVES (AS1) transcription factor plays a critical role in flower and leaf formation by restricting expression of BREVIPEDICELLUS (BP). In as1 mutant flowers, ectopic BP activity shifts the position of the sepal abscission zone, which is restored in as1 bp flowers. In this study we examined whether placement of the lignin brace is regulated by AS1-mediated regulation of BP. Using confocal microscopy and basic fuchsin staining, we observed that deposition of lignin in as1 sepals occurs in an inverted V-shape corresponding to the altered position of the abscission zone. However, while the basal position of these lignified cells is rescued in as1 bp sepals, a distally expanded region of lignified cells was observed in as1 sepals as compared to wild type and other mutants. Taken together, these results suggest that ectopic activity of bp alter the lignification of cells adjacent to the sepal abscission zone.

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Apr 30th, 11:30 AM

AS1 Transcription Factor in Arabidopsis Floral Organ Abscission Zone Shifts Lignin Deposition in an inverted V-Shape

Poster Presenter: Dikshya Niraula

Research Team: Dikshya Niraulaand and Sarah Liljegren

Abstract: Plants have a natural ability to shed organs like leaves, flowers and fruit at specific points during their life cycle. Flowers of the model plant, Arabidopsis thaliana, release their sepals, petals, and stamens after fertilization. Cell separation within specialized abscission zones allows detachment of these floral organs. Within the sepal abscission zone, lignification of a set of cells forms a structural brace that prevents the diffusion of cell wall degrading enzymes. Previous studies have shown that the ASYMMETRIC LEAVES (AS1) transcription factor plays a critical role in flower and leaf formation by restricting expression of BREVIPEDICELLUS (BP). In as1 mutant flowers, ectopic BP activity shifts the position of the sepal abscission zone, which is restored in as1 bp flowers. In this study we examined whether placement of the lignin brace is regulated by AS1-mediated regulation of BP. Using confocal microscopy and basic fuchsin staining, we observed that deposition of lignin in as1 sepals occurs in an inverted V-shape corresponding to the altered position of the abscission zone. However, while the basal position of these lignified cells is rescued in as1 bp sepals, a distally expanded region of lignified cells was observed in as1 sepals as compared to wild type and other mutants. Taken together, these results suggest that ectopic activity of bp alter the lignification of cells adjacent to the sepal abscission zone.