Spatio-Temporal Dynamics of Fructan Metabolism in Developing Barley Grains. Issue 9 (30th September 2014)

• Record Type: Journal Article
• Authors: Peukert, Manuela; Thiel, Johannes; Peshev, Darin; Weschke, Winfriede; Van den Ende, Wim; Mock, Hans-Peter; Matros, Andrea
• Is Part Of: The Plant Cell. Volume 26:Issue 9(2014)
• Page Start: 3728
• Page End: 3744
• Publication Date: 2014-09-30
• DOI: 10.1105/tpc.114.130211
• Languages: English
• ISSNs: 1040-4651

Abstract

Abstract : Fructan metabolism in barley grains is developmental stage and tissue specific. Levans/graminans accumulate in the cellularized endosperm at the prestorage phase, while inulins are enriched in the transfer tissues around the endosperm cavity at the storage phase. This tight partitioning suggests that different fructans have distinct functions in various tissues during barley grain development. Abstract: 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 profiling 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.