Spatio-temporal dynamics of fructan metabolism in developing barley grains
Peukert, Manuela × Thiel, Johannes Peshev, Darin Weschke, Winfriede Van den Ende, Wim Mock, Hans-Peter Matros, Andrea #
American Society of Plant Physiologists
The Plant Cell vol:26 pages:3728-3744
Barley (Hordeum vulgare) grain development follows a series of defined morphological and physiological stages and depends on the supply of assimilates (mainly sucrose) from the mother plant. Here, spatio-temporal patterns of sugar distributions were investigated by mass spectrometric imaging, targeted metabolite analyses, and transcript profi
ling of microdissected grain tissues. Distinct spatio-temporal sugar balances were observed, which may relate to differentiation and grain filling processes. Notably, various types of oligofructans showed specific distribution patterns. Levan- and graminan-type oligofructans were synthesized in the cellularized endosperm prior to the commencement of starch biosynthesis, while during
the storage phase, inulin-type oligofructans accumulated to a high concentration in and around the nascent endosperm
cavity. In the shrunken endosperm mutant seg8 , with a decreased sucrose flux toward the endosperm, fructan accumulation was impaired. The tight partitioning of oligofructan biosynthesis hints at distinct functions of the various fructan types in the young endosperm prior to starch accumulation and in the endosperm transfer cells that accomplish the assimilate supply toward the endosperm at the storage phase.