Fructan Metabolism in Developing Wheat (Triticum aestivum L.) Kernels

Abstract

Although fructans play a crucial role in wheat kernel development, their metabolism during kernel maturation is far from being understood. In this study, all major fructan-metabolizing enzymes together with fructan content, fructan degree of polymerization and the presence of fructan oligosaccharides were examined in developing wheat kernels (Triticum aestivum L. var. Homeros) from anthesis until maturity. Fructan accumulation occurred mainly in the first 2 weeks after anthesis, and a maximal fructan concentration of 2.5 ± 0.3 mg fructan per kernel was reached at 16 days after anthesis (DAA). Fructan synthesis was catalyzed by 1-SST (sucrose:sucrose 1-fructosyltransferase) and 6-SFT (sucrose:fructan 6-fructosyltransferase), and to a lesser extent by 1-FFT (fructan:fructan 1-fructosyltransferase). Despite the presence of 6G-kestotriose in wheat kernel extracts, the measured 6G-FFT (fructan:fructan 6G-fructosyltransferase) activity levels were low. During kernel filling, which lasted from 2 to 6 weeks after anthesis, kernel fructan content decreased from 2.5 ± 0.3 to 1.31 ± 0.12 mg fructan per kernel (42 DAA) and the average fructan degree of polymerization decreased from 7.3 ± 0.4 (14 DAA) to 4.4 ± 0.1 (42 DAA). FEH (fructan exohydrolase) reached maximal activity between 20 and 28 DAA. No fructan-metabolizing enzyme activities were registered during the final phase of kernel maturation, and fructan content and structure remained unchanged. This study provides insight into the complex metabolism of fructans during wheat kernel development and relates fructan turnover to the general phases of kernel development.

Spatio-Temporal Dynamics of Fructan Metabolism in Developing Barley Grains

“…This behavior contrasts with that in total wheat grains, where the highest concentrations of 1-kestose and nystose have been detected before the onset of starch accumulation (Verspreet et al, 2013c). The quantities of 6-kestose and bifurcose (levan-and graminan-type) declined in both the cavity and in the whole grain, consistent with observed spatio-temporal transcript profiles of the genes encoding (A) Scheme of a half-sectioned barley grain at storage stage with enlargement of tissues responsible for nutrient transfer into the endosperm.…”

Stem Reserve Mobilization in Relation to Yield under Different Drought and High Temperature Stress Conditions in Wheat (Triticum aestivum L.) Genotypes

“…Genotype DHTW-60, HD-2967, WH-1105 and HTW-11 was found maximum in yield per square meter (Table 4) under drought situation with delayed sowing. Similar findings have also been reported by various workers (Verspreet, 2015;Munjal & Dhanda, 2016;Zampieri et al, 2017;andRam et al, 2017a, 2017b). Dwivedi et al, (2017) also reported higher reduction in grain yield (60.3%).…”

Soluble carbohydrates in developing and mature diaspores of polar Caryophyllaceae and Poaceae

“…In the generative phase and during kernel development, fructans synthesized and accumulated in shoots are remobilized to supply kernels with additional sucrose (Amiard et al 2003;Zhang et al 2015). Fructans (like 1-kestose) present in immature kernels are used up during starch synthesis during reserve accumulation (Verspreet et al 2013;Peukert et al 2014). In mature cereal kernels, 1-kestose (a-D-glucopyranosyl-(1 ?…”