Sugar metabolism in developing lupin seeds is affected by a short-term water deficit.
A short-term water deficit (WD) imposed during the pre-storage phase of lupin seed development [15-22 d after anthesis (DAA)] accelerated seed maturation and led to smaller and lighter seeds. During seed development, neutral invertase (EC 3.2.1.26) and sucrose synthase (EC 2.4.1.13) have a central role in carbohydrate metabolism. Neutral invertase is predominant during early seed development (up to 40 DAA) and sucrose synthase during the growing and storage phase (40-70 DAA). The contribution of acid invertase is marginal. WD decreased sucrose synthase activity by 2-fold and neutral invertase activity by 5-6-fold. These changes were linked to a large decrease in sucrose ( approximately 60%) and an increase of the hexose:sucrose ratio. Rewatering restored sucrose synthase activity to control levels while neutral invertase activity remained depressed (30-60%). A transient accumulation of starch observed in control seeds was abolished by WD. Despite the several metabolic changes the final seed composition was largely unaltered by WD except for approximately 60% increase in stachyose and raffinose (raffinose family oligosaccharides). This increase in raffinose family oligosaccharides appears as the WD imprinting on mature seeds.
Pinheiro
Carla
C
Instituto de Tecnologia Química e Biológica, Apartado 127, 2781-901 Oeiras, Portugal.
Rodrigues
Ana Paula
AP
de Carvalho
Isabel Saraiva
IS
Chaves
Maria Manuela
MM
Ricardo
Cândido Pinto
CP
D050260:Carbohydrate Metabolism; D003890:Desiccation; D005964:Glucosyltransferases / Q000378:metabolism; D031297:Lupinus / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000378:metabolism; D012639:Seeds / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism*; D014867:Water / Q000032:analysis / Q000378:metabolism*; D043324:beta-Fructofuranosidase / Q000378:metabolism
D014867:Water; D013395:Sucrose; D005964:Glucosyltransferases; C022699:sucrose synthase; D043324:beta-Fructofuranosidase