title: Wheat genotypic variation in dynamic fluxes of WSC components in different stem segments under drought during grain filling.
abstract: In wheat, stem water soluble carbohydrates (WSC), composed mainly of fructans, are the major carbon sources for grain filling during periods of decreasing photosynthesis or under drought stress after anthesis. Here, in a field drought experiment, WSC levels and associated enzyme activities were followed in different stem segments (peduncle, penultimate internode, lower parts of stem, and sheath) during grain filling. The focus was on two double haploid (DH) lines, DH 307 and DH 338, derived from a Westonia/Kauz cross, two drought-tolerant wheat varieties that follow different drought adaptation strategies during grain filling. The results showed that in irrigated plants, in the period between 20 and 30 days after anthesis (DAA), 70-80% of WSC were fructans. Before and after this period, the fructan proportion varied from 10 to 60%, depending on the location along the stem. Under drought, the fructan proportion changed, depending on genotype, and developmental stages. After anthesis, stem fructans accumulation occurred mainly in the peduncle and penultimate internode until 14 DAA in both DH lines, with clear genotypic variation in subsequent fructan degradation under drought. In DH 307 a significant reduction of fructans with a concomitant increase in fructose levels occurred earlier in the lower parts of the stem and the sheath, as compared to DH 338 or other stem segments in both lines. This was associated with an earlier increase of grain weight and thousand grain weight in DH 307. Spatiotemporal analysis of fructan dynamics and enzymatic activities in fructan metabolism revealed that several types of FEHs are involved in fructan remobilization to the grain under drought.
authors: Agricultural Sciences, School of Veterinary and Life Sciences, Murdoch University Murdoch, WA, Australia.
authors: Jingjuan
authors: J
authors: Zhang
authors: State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources Yangling, Shaanxi, China.
authors: Wei
authors: W
authors: Chen
authors: Agricultural Sciences, School of Veterinary and Life Sciences, Murdoch University Murdoch, WA, Australia.
authors: Bernard
authors: B
authors: Dell
authors: Lab of Molecular Plant Biology, Institute of Botany and Microbiology, KU Leuven Leuven, Belgium.
authors: Rudy
authors: R
authors: Vergauwen
authors: Agricultural Sciences, School of Veterinary and Life Sciences, Murdoch University Murdoch, WA, Australia.
authors: Xinmin
authors: X
authors: Zhang
authors: Grains Research and Development Corporation Barton, ACT, Australia.
authors: Jorge E
authors: JE
authors: Mayer
authors: Lab of Molecular Plant Biology, Institute of Botany and Microbiology, KU Leuven Leuven, Belgium.
authors: Wim
authors: W
authors: Van den Ende
keywords: 6-kestose; fructan exohydrolase (FEH); fructan remobilization; grain weight (GW); stem segments; stem water soluble carbohydrates (WSC)