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Title: Comparative expression analysis of hordein and beta-amylase in developing barley grains

item Vinje, Marcus

Submitted to: Proceedings International Barley Genetics Symposium
Publication Type: Proceedings
Publication Acceptance Date: 1/7/2016
Publication Date: 6/26/2016
Citation: Vinje, M.A. 2016. Comparative expression analysis of hordein and beta-amylase in developing barley grains. Proceedings International Barley Genetics Symposium. #203.

Interpretive Summary:

Technical Abstract: Hordeins are the major seed storage proteins (SSP) in the barley grain. They account for the majority of all proteins in the mature grain. Hordeins accumulate and are stored during grain development. Their primary function is to act as nitrogen, carbon, and sulfur reserves. Beta-amylase is a starch degrading enzyme that is important to fermentable sugar production during malting. Beta-amylase is different from the other enzymes involved in fermentable sugar production in that it is expressed and stored in the developing grain in a similar pattern as the hordeins. Previous studies have shown an increased amount of hordein and beta-amylase in the mature grain when barley is exposed to nitrogen, drought, and heat. Beta-amylase has been long speculated to be a SSP or have a dual function as an enzyme and a SSP. High beta-amylase activity is a desirable trait as it is positively and significantly correlated to diastatic power. However, high levels of beta-amylase are correlated to high levels of hordeins and total protein. In order for barley to meet malting quality standards protein levels must be within a defined range. Increased beta-amylase levels can potentially lead to barley not making malting quality due to high total protein levels. The expression patterns of hordein and beta-amylase were determined in developing barley caryopsis from 5 days after anthesis (DAA) to 35 DAA to assess whether there is an exploitable difference between hordein and beta-amylase accumulation.