Recent research reveals that starch degradation in Arabidopsis leaves at night is significantly different from the "textbook" version of this process. Although parts of the pathway are now understood, other parts remain to be discovered. Glucans derived from starch granules are hydrolyzed via β-amylase to maltose, which is exported from the chloroplast. In the cytosol maltose is the substrate for a transglucosylation reaction, producing glucose and a glucosylated acceptor molecule. The enzyme that attacks the starch granule to release glucans is not known, nor is the nature of the cytosolic acceptor molecule. An Arabidopsis-type pathway may operate in leaves of other species, and in nonphotosynthetic organs that accumulate starch transiently. However, in starch-storing organs such as cereal endosperms and legume seeds, the process differs from that in Arabidopsis and may more closely resemble the textbook pathway. We discuss the differences in relation to the biology of each system.

Item Type:	Refereed Article
Keywords:	amylase, Arabidopsis, cereal endosperm, chloroplast, maltose
Research Division:	Biological Sciences
Research Group:	Plant Biology
Research Field:	Plant Physiology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Biological Sciences
Author:	Smith, SM (Professor Steven Smith)
ID Code:	101520
Year Published:	2005
Web of Science® Times Cited:	305
Deposited By:	Plant Science
Deposited On:	2015-06-25
Last Modified:	2015-09-25
Downloads:	0