Aleurones from a Barley with Low [alpha]-Amylase Activity Become Highly Responsive to Gibberellin When Detached from the Starchy Endosperm

Abstract

The physiological and molecular bases for contrasting a-amylase phenotypes were examined in germinating seeds of two barley (Hordeum vurgare 1.) cultivars, Morex and Steptoe. Morex is a high-quality malting barley that develops high a-amylase activity soon after germination. Steptoe is a feed barley that develops only low a-amylase activity levels during this period. l h e expression of all high-and low-isoelectric point (pl) a-amylase isozymes is reduced in Steptoe. The amount of a-amylase mRNA per gram of seedling tissue is correspondingly lower in Steptoe. Southern blot analysis revealed that the cultivars have the same copy number and organization for most high-and low-pl genes. Steptoe seedlings or embryoless half-seeds produce little a-amylase in response to exogenous applications of gibberellic acid (CA,) compared with Morex. However, when isolated aleurones of both cultivars are treated with GA3, they produce similar amounts of high-and lowpl a-amylase RNAs. This suggests that a factor in the starchy endosperm is responsible for lowered a-amylase response in Steptoe. l h e factor is probably not abscisic acid (ABA), since the two cultivars have similar concentrations of ABA during germination.

Integrated control of seed maturation and germination programs by activator and repressor functions of Viviparous-1 of maize.

“…This view is supported by our results showing that overexpression of VP1 in aleurone of germinating maize seeds was effective in repressing Amy-GUS (Table 2). A role of VP1 in maintaining seed dormancy is also consistent with the finding that dormancy in barley is correlated with a reduced GA inducibility of a-amylase genes in the aleurone (Schuurink et al 1992;Skadsen 1993). Hence, we suggest that VP1 plays a role in integrating the control of seed maturation, dormancy, and germination programs.…”

Improving the Field Emergence Performance of Super Sweet Corn by Sand Priming

“…Farooq et al (2006) considered that the higher the α-amylase activity the higher would be metabolic activity in seeds, which indicated the higher germination ability. Skadsen (1993) reported that higher quality malting barley showed high α-amylase activity soon after germination, whereas a poor malting quality variety showed little α-amylase activity. In this study, sand priming improved α-amylase activity and accelerated the increase of α -amylase activity during seed germination.…”

Spatial and Temporal Divergence of Expression in Duplicated Barley Germin-Like Protein-Encoding Genes

“…Ovary and anther RNAs were extracted using an RNeasy kit (QIAGEN). Seed RNAs were extracted as described (Skadsen 1993). Pericarp RNA for differential display was extracted from Morex seeds at the early dough stage of development.…”