PT  - JOURNAL ARTICLE
AU  - Niittylä, Totte
AU  - Messerli, Gaëlle
AU  - Trevisan, Martine
AU  - Chen, Jychian
AU  - Smith, Alison M.
AU  - Zeeman, Samuel C.
TI  - A Previously Unknown Maltose Transporter Essential for Starch Degradation in Leaves
AID  - 10.1126/science.1091811
DP  - 2004 Jan 02
TA  - Science
PG  - 87--89
VI  - 303
IP  - 5654
4099  - http://science.sciencemag.org/content/303/5654/87.short
4100  - http://science.sciencemag.org/content/303/5654/87.full
SO  - Science2004 Jan 02; 303
AB  - A previously unknown maltose transporter is essential for the conversion of starch to sucrose in Arabidopsis leaves at night. The transporter was identified by isolating two allelic mutants with high starch levels and very high maltose, an intermediate of starch breakdown. The mutations affect a gene of previously unknown function, MEX1. We show that MEX1is a maltose transporter that is unrelated to other sugar transporters. The severe mex1 phenotype demonstrates that MEX1is the predominant route of carbohydrate export from chloroplasts at night. Homologous genes in plants including rice and potato indicate that maltose export is of widespread significance.