The expression of the gene associated with β-glucan content, β-amylase and limit dextrinase synthesis as affected by post-heading heat stress in barley

Abstract

Background: Malt barley shows a dramatic deterioration of malt quality when exposed to heat or high temperature stress during grain-filling stage (post heading), and global change results in the more frequent occurrence of high temperature, posing a severe threat to high-quality malt barley production. In a previous study, we found heat stress during grain-filling stage caused the significant reduction of kernel weight, and the significant increase of protein and β-glucan content, and βamylase and limit dextrinase (LD) activities, and the effect varied with barley genotypes and the time of heat stress exposure.Results: In this study, we determined the relative expressions of HvCslF6 and HvCslF9 for β-glucan, HvBmy1 for β-amylase and LD gene for limit dextrinase of two barley cultivars ZU9 and Hua30 under the two heat stress (HS) treatments (32/26℃, day/night), initiated from the 7th day (early grain-filling stage) and the14th day (middle grain-filling stage) after heading. In comparison with normal temperature (24/18℃, day/night), HS treatments significantly up-regulated the relative expression of all four genes, and Hua30 being larger than ZU9. The change pattern of each examined gene for the two barley genotypes under heat stress treatments is completely consistent with that of corresponding malt quality trait as affected by heat stress. Conclusion:The results indicate that the enhancement of β-glucan content, and β-amylase and limit dextrinase activities under high temperature during grain filling stage is at least in part attributed to increased expression of the relevant genes. BackgroundHeat or high temperature stress is one of the most common natural disasters affecting crop production, and is becoming more severe because of global climate change, posing a great threat to agricultural sustainability [1]. Heat stress not only reduces crop yield due to its direct damage on plant growth and development, but also deteriorates quality of end products through disordering metabolisms and metabolite transportation [2][3].

Effect of terminal heat stress on osmolyte accumulation and gene expression during grain filling in bread wheat (Triticum aestivum L.)

“…Ni et al. (2019) studied the relative expression of HvCslF6 in two barley cultivars (Hua30 and ZU9) at 32°C during the early and late grain filling stages. A significant increase in the relative expression of HvCslF6 was noticed in both cultivars under heat stress compared to the control temperature (24°C).…”

“…Previously, it has been shown that the overexpression of CslF6 gene caused a greater than 80% increase in 1,3;1,4β-glucan in transgenic barley grains (Burton et al, 2011). Ni et al (2019) studied the relative expression of HvC-slF6 in two barley cultivars (Hua30 and ZU9) at 32˚C during the early and late grain filling stages. A significant increase in the relative expression of HvCslF6 was noticed in both cultivars under heat stress compared to the control temperature (24˚C).…”