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United States Department of Agriculture

Agricultural Research Service

Research Project: RESPONSE OF DIVERSE RICE GERMPLASM TO BIOTIC AND ABIOTIC STRESSES Title: Structural and expressional analysis of the B-hordein genes in Tibetan hull-less barley

Authors
item Han, Zhaoxue - CHINESE ACAD. OF SCIENCE
item Wu, Fang - CHINESE ACAD. OF SCIENCE
item Deng, Guangbing - CHINESE ACAD. OF SCIENCE
item Qian, Gang - CHINESE ACAD. OF SCIENCE
item Yu, Maoqun - CHINESE ACAD. OF SCIENCE
item Jia, Yulin

Submitted to: Genetica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 9, 2009
Publication Date: October 24, 2009
Citation: Han, Z., Wu, F., Deng, G., Qian, G., Yu, M., Jia, Y. 2009. Structural and expressional analysis of the B-hordein genes in Tibetan hull-less barley. Genetica. 138-227-239.

Interpretive Summary: The B-hordeins protein, the major storage protein in the endosperm is one of the major factors affecting food processing, malting and feed quality of barley. In cooperation with scientists at Chengdu Institute of Biology, the Chinese Academy of Sciences, the B-hordein gene family was sequenced from two Tibetan hull-less barley cultivars, Z09 and Z26 (Hordeum vulgare subsp. vulgare). A total of fourteen B-hordein genes, designated BZ09-2 to BZ09-5 (from Z09) and BZ26-1 to BZ26-10 (from Z26), were analyzed. A common motif was identified from these putative proteins, however, a large variation was observed between numbers of repeat units of predicted B-hordeins in cvs Z26 and Z09. Phylogenetic analysis revealed that all BZ26 clones were clustered in a subgroup, and BZ09-1 formed another subgroup by itself in the putative eight active genes. In addition, six 5’-upstream regulatory sequences of the B-hordein genes were isolated by the use of single oligonucleotide nested PCR technology, and several mutations were identified in the cis-acting element and two distinctive sequences (Z09P-2 and Z26P-3). Quantitative real time PCR analysis indicates distinct expression levels of B-hordein genes in four developing stages of developing grains in these two cultivars. These findings suggest the B-hordein genes have intrinsic expression differences between accessions, and this knowledge is useful for incorporating the B-hordeins protein in barley breeding programs.

Technical Abstract: The B-hordein gene family was analyzed from two Tibetan hull-less barley cultivars, Z09 and Z26 (Hordeum vulgare subsp. vulgare). Fourteen B-hordein genes, designated BZ09-2 to BZ09-5 (from Z09) and BZ26-1 to BZ26-10 (from Z26), were sequenced. Seven of them similar to a previously reported BZ09-1 from Z09 were predicted to encode putative active proteins each with a signal peptide, a repetitive domain, a C-terminal region, and seven of them were predicted to be pseudogenes. The B-hordein gene family was analyzed using all known representatives of B-hordein sequences, and two most similar LMW-GSs of Triticum aestivum. Alignment of these seven putative proteins with known B-hordeins and two most similar LMW-GSs of T. aestivum revealed that they shared a common motif. A large variation was observed between numbers of repeat units of predicted B-hordeins of Z26 and Z09. Phylogenetic analysis revealed that all BZ26 clones were clustered in a subgroup, and BZ09-1 formed another subgroup by itself in the putative eight active genes. In addition, six 5’-upstream regulatory sequences of the B-hordein genes were isolated from the two accessions by single oligonucleotide nested PCR (SON-PCR), and several different mutations were identified in the cis-acting element GLM and two distinctive sequences (Z09P-2 and Z26P-3). Phylogenetic analysis of 5’-upstream regulatory regions of the B-hordein genes showed the members from the same accession were clustered together with the exception of two distinctive members. Quantitative real time PCR analysis indicates distinct expression levels of B-hordein genes in four developing stages of developing grains in two accessions. These findings suggest B-hordein genes have intrinsicdifferences between accessions. This knowledge is useful for incorporating the B-hordeins protein in barley breeding programs.

Last Modified: 11/27/2014
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