AUTHOR=Zhang Qisen , Li Chengdao 

TITLE=Comparisons of Copy Number, Genomic Structure, and Conserved Motifs for α-Amylase Genes from Barley, Rice, and Wheat

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.01727

DOI=10.3389/fpls.2017.01727

ISSN=1664-462X

ABSTRACT=<p>Barley is an important crop for the production of malt and beer. However, crops such as rice and wheat are rarely used for malting. α-amylase is the key enzyme that degrades starch during malting. In this study, we compared the genomic properties, gene copies, and conserved promoter motifs of α-amylase genes in barley, rice, and wheat. In all three crops, α-amylase consists of four subfamilies designated <italic>amy1, amy2</italic>, <italic>amy3</italic>, and <italic>amy4</italic>. In wheat and barley, members of <italic>amy1</italic> and <italic>amy2</italic> genes are localized on chromosomes 6 and 7, respectively. In rice, members of <italic>amy1</italic> genes are found on chromosomes 1 and 2, and <italic>amy2</italic> genes on chromosome 6. The barley genome has six <italic>amy1</italic> members and three <italic>amy2</italic> members. The wheat B genome contains four <italic>amy1</italic> members and three <italic>amy2</italic> members, while the rice genome has three <italic>amy1</italic> members and one <italic>amy2</italic> member. The B genome has mostly <italic>amy1</italic> and <italic>amy2</italic> members among the three wheat genomes. <italic>Amy1</italic> promoters from all three crop genomes contain a GA-responsive complex consisting of a GA-responsive element (CAATAAA), pyrimidine box (CCTTTT) and TATCCAT/C box. This study has shown that <italic>amy1</italic> and <italic>amy2</italic> from both wheat and barley have similar genomic properties, including exon/intron structures and GA-responsive elements on promoters, but these differ in rice. Like barley, wheat should have sufficient amy activity to degrade starch completely during malting. Other factors, such as high protein with haze issues and the lack of husk causing Lauting difficulty, may limit the use of wheat for brewing.</p>