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About the Authors:
Olin D. Anderson
* E-mail: [email protected]
Affiliation: Genomics and Gene Discovery Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, California, United States of America
Lingli Dong
Affiliations Genomics and Gene Discovery Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, California, United States of America, The Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
Naxin Huo
Affiliations Genomics and Gene Discovery Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, California, United States of America, Department of Plant Sciences, University of California Davis, Davis, California, United States of America
Yong Q. Gu
Affiliation: Genomics and Gene Discovery Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, California, United States of America
Introduction
The γ-type seed prolamins are widely distributed within the Triticeae, have been studied most extensively in wheat (γ-gliadins), barley (γ-hordeins), and rye (γ-secalins), and have been proposed to be the most ancestral of the Triticeae prolamins [1]. The wheat γ-gliadins are estimated of to be encoded by 15–40 genes [2], and there are some 200 γ-gliadin sequences in Genbank for Triticum aestivum (bread wheat) plus more from other Triticum species and Triticeae genera. The barley γ-hordeins are not as well studied, but have been tentatively separated into γ1, γ2, and γ3 classes based on limited data from electrophoretic mobility of barley seed proteins, N-terminal sequences, and antibody specificity [3], [4]. However, there are relatively few gene sequences for barley γ-hordeins in Genbank; e.g., only two Hordeum vulgare γ3-hordein sequences – one covering a complete coding region (AK251750, [5]) and a partial sequence (X72628, [6]) along with 21 partial or complete more divergent H. chilense coding sequences [7]. Both γ1 and γ2 barley probes of Genbank return the same three matches (X13508 [8], M36378 [8], and AJ580585 [9]: M36378 and X13508 are the same sequence. The reports and Genbank entries assign AJ580585 as a γ2-hordein and M36378 as a γ1-hordein. The original classification was initially based on factors which have only a potential relationship to evolutionary connection of gene sequences and are not definitive....