Storage product synthesis and accumulation in developing grains of wheat

Polymerisation of gluten proteins in developing wheat grain as affected by desiccation

“…The majority of HMW-GS and LMW-GS were found in the F1* and F1 fractions at 40 DAA, which revealed that an increase in the molecular weight of glutenin were assembled to large polymers during grain desiccation after YR. This is in accordance with previous reports (Carceller and Aussenac, 1999;Gupta et al, 1996;Shewry et al, 2009). A similar polymerisation pattern was observed during the desiccation of premature grain harvested at 10 and 25 DAA in the 2011 season (Supplemental figure B (A), (B), (D), and (E)).…”

“…The results indicated that polymerisation of large glutenin polymers was not caused by desiccation itself, but desiccation obviously initiated the polymerisation process, which was also suggested previously (Carceller and Aussenac, 1999;Gupta et al, 1996;Shewry et al, 2009). The desiccation process probably activates enzyme activities that are involved in folding and polymerisation of glutenin polymers as Osipova et al It has been reported that the rheological properties of dough are influenced by the size distribution of glutenin polymers (Gupta et al, 1993).…”

“…Daniel and Triboi (2002) evaluated the effects of environmental factors, particularly temperature and drought, on the aggregation of gluten proteins and showed that drought caused the early onset of the rapid polymerisation of gluten proteins leading to poor solubility. From these results, Shewry et al (2009) suggested that grain desiccation at the end of grain development drives protein polymerisation, which leads to an increase in the molecular weight of glutenin polymers. However, the number of publications reporting the time course of the accumulation of gluten proteins as well as the polymerisation of glutenin subunits during grain development and desiccation, is still limited.…”

“…Tosi et al (2009) observed gluten protein bodies in developing grain as early as 8 days after anthesis (DAA). Shewry et al (2009) reported that low molecular weight-glutenin subunits (LMW-GS) and gliadins were synthesised and accumulated most rapidly between 12 DAA and 35 DAA, while high molecular weight-glutenin subunits (HMW-GS) accumulated more slowly but for a longer period during grain filling. Glutenin subunits are linked by intermolecular disulphide bonds and form large glutenin polymers with molecular weights ranging from about 500,000 to more than 10 million (Shewry and Tatham, 1997;Wahlund et al, 1996).…”

“…Moreover, the proportion of the largest glutenin polymers, known as sodium dodecylsulphate-(SDS) unextractable polymeric proteins (UPP) or glutenin macropolymer (GMP), are associated with the strength and the elasticity of dough (Don et al, 2003;Gupta et al, 1993). The size of these glutenin polymers is controlled to a large extent by genotype (the composition of HMW-GS as well as LMW-GS) but also by environmental effects (Gupta and MacRitchie, 1994;Moldestad et al, 2014) The initial assembly of glutenin subunits into glutenin polymers occurs shortly after synthesis, while the rapid increase in the molecular weight of glutenin polymers occurs during the desiccation/maturation phase at the end of grain development (Carceller andAussenac, 1999, 2001;Daniel and Triboi, 2002;Shewry et al, 2009). Carceller and Aussenac (2001) demonstrated the close relationship between the composition of glutenin polymers, particularly the ratio of HMW-GS to LMW-GS, and the polymerisation index (SDS-insoluble polymers/total polymers), when premature grains were desiccated during the cell enlargement phase.…”