文章基本信息

标题：Dynamic Evolution of α-Gliadin Prolamin Gene Family in Homeologous Genomes of Hexaploid Wheat
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作者：Naxin Huo ; Tingting Zhu ; Susan Altenbach 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2018
卷号：8
期号：1
页码：5181
DOI：10.1038/s41598-018-23570-5
语种：English
出版社：Springer Nature
摘要：Wheat Gli-2 loci encode complex groups of α-gliadin prolamins that are important for breadmaking, but also major triggers of celiac disease (CD). Elucidation of α-gliadin evolution provides knowledge to produce wheat with better end-use properties and reduced immunogenic potential. The Gli-2 loci contain a large number of tandemly duplicated genes and highly repetitive DNA, making sequence assembly of their genomic regions challenging. Here, we constructed high-quality sequences spanning the three wheat homeologous α-gliadin loci by aligning PacBio-based sequence contigs with BioNano genome maps. A total of 47 α-gliadin genes were identified with only 26 encoding intact full-length protein products. Analyses of α-gliadin loci and phylogenetic tree reconstruction indicate significant duplications of α-gliadin genes in the last ~2.5 million years after the divergence of the A, B and D genomes, supporting its rapid lineage-independent expansion in different Triticeae genomes. We showed that dramatic divergence in expression of α-gliadin genes could not be attributed to sequence variations in the promoter regions. The study also provided insights into the evolution of CD epitopes and identified a single indel event in the hexaploid wheat D genome that likely resulted in the generation of the highly toxic 33-mer CD epitope.