Starch accumulation in bean fruit pericarp is mediated by the differentiation of chloroplasts into amyloplasts
Por:
Belmont, Raymundo, Bernal, Lilia, Padilla-Chacon, Daniel, Coello, Patricia, Martinez-Barajas, Eleazar
Publicada:
1 mar 2022
Resumen:
The sucrose supply to bean fruits remains almost constant during seed
development, and the early stages of this process are characterized by a
significant amount of starch and soluble sugars (glucose, fructose and
sucrose) accumulated in the pericarp. Bean fruits are photosynthetically
active; however, our results indicated that starch synthesis in the
pericarp was largely dependent on the photosynthetic activity of the
leaves. The photosynthetic activity and the amount of the Rubisco large
subunit were gradually reduced in the fruit pericarp, and a large
increase in the amount of the ADP-glucose pyrophosphorylase small
subunit (AGPase SS) was observed. These changes suggested
differentiation of chloroplasts into amyloplasts. Pericarp chloroplasts
imported glucose 1-P to support starch synthesis, and their
differentiation into amyloplasts allowed the surplus sucrose to be used
in the synthesis of starch, which was later degraded to meet the needs
of fast-growing seeds. Starch stored in the bean fruit pericarp was not
degraded in response to drought stress, but it was rapidly used under
severe nutrient restriction. Together, this work indicated that starch
accumulation in the pericarp of bean fruits is important to adjust the
needs of developing seeds to the amount of sucrose that is provided to
fruits.
Filiaciones:
Belmont, Raymundo:
UNAM, Fac Quim, Dept Bioquim, Cdmx 04510, Mexico
Bernal, Lilia:
UNAM, Fac Quim, Dept Bioquim, Cdmx 04510, Mexico
Padilla-Chacon, Daniel:
CONACyT Colegio Posgrad, Bot, Km 36-5 Carretera Mexico Texcoco, Montecillo 56230, MX, Mexico
Coello, Patricia:
UNAM, Fac Quim, Dept Bioquim, Cdmx 04510, Mexico
Martinez-Barajas, Eleazar:
UNAM, Fac Quim, Dept Bioquim, Cdmx 04510, Mexico
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