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Wheat grain Avenin-like protein dynamics in relation to genotypes and environments

Zhang, Yujuan (2018) Wheat grain Avenin-like protein dynamics in relation to genotypes and environments. PhD thesis, Murdoch University.

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Abstract

The recently discovered non-gluten prolamins, avenin-like proteins (ALPs) in wheat can improve flour baking qualities. In our study, 15 TaALP genes were identified and mapped to chromosomes 7A, 4A and 7D. Phylogenetic analysis showed that TaALP genes formed three major clades, types a, b, and c. The allelic variation of ALP genes in a wild emmer wheat (Triticum turgidum ssp. dicoccoides) populations from Israel were investigated to study the evolution of TdALP genes under different micro environments. In total, 49 alleles were identified at 4 TdALP loci. Correlations between the sites in which wild emmer wheat accessions were collected in Israel and the diversity of their ALP allelles suggested that at least some alleles were selected for by environmental factors.

In this project, we found that TaALP genes are pathogen-inducible. Bioinformatics predicted the presence of pathogenesis-related nucleotide motifs in the promoter regions of TaALP genes. Expression levels of TaALP genes and some PR genes were analysed by quantitative RT-PCR in developing caryopses at 7, 13 and 42 days after pollination. Differential expression patterns of TaALP genes were identified in plants infected by Fusarium graminearum. Recombinant TaALP-encoded proteins significantly inhibited the fungal growth in vitro. mRNA in situ hybridization confirmed that TaALP transcripts were upregulated in aleurone, sub-aleurone, and embryos after infection. Genome-wide Fusarium head blight (FHB) index association analysis indicated that certain TaALP alleles were significantly correlated with FHB resistance. The ALPs may act as pathogen resistance proteins mediated by systemic acquired resistance (SAR). Our research indicated that TaALP genes, characterized by typical gliadin domains, are broad-spectrum, partial-resistance genes that contribute to sustainable control of wheat pathogen disease and possibly other fungus-induced disease in wheat. This exciting finding will be applicable for breeding broad range of disease-tolerant and high-quality wheat varieties for sustainable wheat production.

Item Type: Thesis (PhD)
Murdoch Affiliation: School of Veterinary and Life Sciences
United Nations SDGs: Goal 12: Responsible Consumption and Production
Supervisor(s): Ma, Wujun, Dell, Bernard and Wylie, Steve
URI: http://researchrepository.murdoch.edu.au/id/eprint/43015
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