Blocking the metabolism of starch breakdown products in Arabidopsis leaves triggers chloroplast degradation.

ABSTRACT: In most plants, a large fraction of photo-assimilated carbon is stored in the chloroplasts during the day as starch and remobilized during the subsequent night to support metabolism. Mutations blocking either starch synthesis or starch breakdown in Arabidopsis thaliana reduce plant growth. Maltose is the major product of starch breakdown exported from the chloroplast at night. The maltose excess 1 mutant (mex1), which lacks the chloroplast envelope maltose transporter, accumulates high levels of maltose and starch in chloroplasts and develops a distinctive but previously unexplained chlorotic phenotype as leaves mature. The introduction of additional mutations that prevent starch synthesis, or that block maltose production from starch, also prevent chlorosis of mex1. In contrast, introduct

SUBMITTER: Stettler M 

PROVIDER: S-EPMC2782796 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature