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Summary: De‐domestication is a unique evolutionary process during which crops re‐acquire wild‐like traits to survive and persist in agricultural fields without the need for human cultivation. The re‐acquisition of seed dispersal mechanisms is crucial for crop de‐domestication. Common wheat is an important cereal crop worldwide. Tibetan semi‐wild wheat is a potential de‐domesticated common wheat subspecies. However, the crucial genes responsible for its brittle rachis trait have not been identified.Genetic mapping, functional analyses and phylogenetic analyses were completed to identify the gene associated with Qbr.sau‐5A, which is a major locus for the brittle rachis trait of Tibetan semi‐wild wheat.The cloned Qbr.sau‐5A gene is a new Q allele (Qt) with a 161‐bp transposon insertion in exon 5. Although Qt is expressed normally, its encoded peptide lacks some key features of the APETALA2 family. The abnormal functions of Qt in developing wheat spikes result in brittle rachises. Phylogenetic and genotyping analyses confirmed that Qt originated from Q in common wheat and is naturally distributed only in Tibetan semi‐wild wheat populations.The identification of Qt provides new evidence regarding the origin of Tibetan semi‐wild wheat, and new insights into the re‐acquisition of wild traits during crop de‐domestication. See also the Commentary on this article by Ellstrand, 224: 550–551. [ABSTRACT FROM AUTHOR]

Background: Phytohormones are key regulators of plant growth, development, and signalling networks involved in responses to diverse biotic and abiotic stresses. Transcriptional reference maps of hormone responses have been reported for several model plant species such as Arabidopsis thaliana, Oryza sativa, and Brachypodium distachyon. However, because of species differences and the complexity of the wheat genome, these transcriptome data are not appropriate reference material for wheat studies. Results: We comprehensively analysed the transcriptomic responses in wheat spikes to seven phytohormones, including indole acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA), ethylene (ET), cytokinin (CK), salicylic acid (SA), and methyl jasmonic acid (MeJA). A total of 3386 genes were differentially expressed at 24 h after the hormone treatments. Furthermore, 22.7% of these genes exhibited overlapping transcriptional responses for at least two hormones, implying there is crosstalk among phytohormones. We subsequently identified genes with expression levels that were significantly and differentially induced by a specific phytohormone (i.e., hormone-specific responses). The data for these hormone-responsive genes were then compared with the transcriptome data for wheat spikes exposed to biotic (Fusarium head blight) and abiotic (water deficit) stresses. Conclusion: Our data were used to develop a transcriptional reference map of hormone responses in wheat spikes. [ABSTRACT FROM AUTHOR]

Fusarium graminearum causes Fusarium head blight (FHB), a devastating disease of wheat. Salicylic acid (SA) is involved in the resistance of wheat to F. graminearum. Cell wall mannoprotein (CWM) is known to trigger defense responses in plants, but its role in the pathogenicity of F. graminearum remains unclear. Here, we characterized FgCWM1 (FG05_11315), encoding a CWM in F. graminearum. FgCWM1 was highly expressed in wheat spikes by 24 h after initial inoculation and was upregulated by SA. Disruption of FgCWM1 (ΔFgCWM1) reduced mannose and protein accumulation in the fungal cell wall, especially under SA treatment, and resulted in defective fungal cell walls, leading to increased fungal sensitivity to SA. The positive role of FgCWM1 in mannose and protein accumulation was confirmed by its expression in Saccharomyces cerevisiae. Compared with wild type (WT), ΔFgCWM1 exhibited reduced pathogenicity toward wheat, but it produced the same amount of deoxynivalenol both in culture and in spikes. Complementation of ΔFgCWM1 with FgCWM1 restored the WT phenotype. Localization analyses revealed that FgCWM1 was distributed on the cell wall, consistent with its structural role. Thus, FgCWM1 encodes a CWM protein that plays an important role in the cell wall integrity and pathogenicity of F. graminearum. [ABSTRACT FROM AUTHOR]