Cell type-specific gene expression underpins remodelling of cell wall pectin in exocarp and cortex during apple fruit development.
J Exp Bot
; 70(21): 6085-6099, 2019 11 18.
Article
en En
| MEDLINE
| ID: mdl-31408160
ABSTRACT
In apple (Malus×domestica) fruit, the different layers of the exocarp (cuticle, epidermis, and hypodermis) protect and maintain fruit integrity, and resist the turgor-driven expansion of the underlying thin-walled cortical cells during growth. Using in situ immunolocalization and size exclusion epitope detection chromatography, distinct cell type differences in cell wall composition in the exocarp were revealed during apple fruit development. Epidermal cell walls lacked pectic (1â4)-ß-d-galactan (associated with rigidity), whereas linear (1â5)-α-l-arabinan (associated with flexibility) was exclusively present in the epidermal cell walls in expanding fruit and then appeared in all cell types during ripening. Branched (1â5)-α-l-arabinan was uniformly distributed between cell types. Laser capture microdissection and RNA sequencing (RNA-seq) were used to explore transcriptomic differences controlling cell type-specific wall modification. The RNA-seq data indicate that the control of cell wall composition is achieved through cell-specific gene expression of hydrolases. In epidermal cells, this results in the degradation of galactan side chains by possibly five ß-galactosidases (BGAL2, BGAL7, BGAL10, BGAL11, and BGAL103) and debranching of arabinans by α-arabinofuranosidases AF1 and AF2. Together, these results demonstrate that flexibility and rigidity of the different cell layers in apple fruit during development and ripening are determined, at least in part, by the control of cell wall pectin remodelling.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Pared Celular
/
Pectinas
/
Regulación de la Expresión Génica de las Plantas
/
Malus
/
Frutas
Idioma:
En
Revista:
J Exp Bot
Asunto de la revista:
BOTANICA
Año:
2019
Tipo del documento:
Article
País de afiliación:
Nueva Zelanda