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. 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. Our data were used to develop a transcriptional reference map of hormone responses in wheat spikes.

Wheat grain serves as the primary raw material for producing medium-high temperature (MT)-Daqu, a fermentation starter crucial for Chinese Baijiu production, characterized by spontaneous fermentation without the inoculation of exogenous substances. However, the interactions among wheat varieties, cultivation environments, and the resulting Daqu quality remain poorly understood. This study evaluates three wheat varieties harvested from three distinct cultivation environments, examining wheat grain quality, grain-associated endophytes, and physicochemical properties and microbial communities of MT-Daqu at 0, 9, and 90 days of fermentation. The results revealed the cultivation environment had the most pronounced impact on wheat fungal endophytes. The physicochemical properties of Daqu were primarily impacted by variety, namely, the enzyme activity impacted by environmental factors. Pantoea, Aspergillus, and Stephylium are key microbial genera shared between wheat grains and MT-Daqu. Redundancy analysis highlighted the critical roles of moisture content, starch content, and amino acid nitrogen levels in driving microbial succession in Daqu. Mantel analysis demonstrated significant correlations between the abundance of dominant fungal endophytes in wheat grains and Daqu quality parameters, including starch content (r = 0.45; p < 0.01), saccharifying activity (r = 0.41), liquefying activity (r = 0.31), and esterifying activity (r = 0.30) (p < 0.05). Spearman correlation analysis indicated that Nesterenkonia, Aspergillus, Cryptococcus, Dioszegia, Golubevia, Udeniomyces and Stemphylium are the dominant wheat-derived bacterial genera associated with the abundance of microorganisms in MT-Daqu. This study elucidated the “cultivation environment–grain endophyte–Daqu microorganism” microbial transmission pathway, providing a theoretical foundation for breeding wheat varieties optimized for Daqu production and identifying suitable production regions.

Chinese wheat landrace Anyuehong (AYH) has displayed high levels of stable adult plant resistance (APR) to stripe rust for >15 years. To identify quantitative trait loci (QTLs) for stripe rust resistance in AYH, a set of 110 recombinant inbred lines (RILs) was developed from a cross between AYH and susceptible cultivar Taichung 29. The parents and RILs were evaluated for final disease severity (FDS) in six field tests with a mixture of predominant Puccinia striiformis f. sp. tritici races at the adult plant stage and genotyped via the wheat 55K single-nucleotide polymorphism (SNP) array to construct a genetic map with 1,143 SNP markers. Three QTLs, designated as QYr.AYH-1AS, QYr.AYH-5BL, and QYr.AYH-7DS, were mapped on chromosome 1AS, 5BL, and 7DS, respectively. RILs combining three QTLs showed significantly lower FDS compared with the lines in other combinations. Of them, QYr.AYH-5BL and QYr.AYH-7DS were stably detected in all environments, explaining 13.6 to 21.4% and 17.6 to 33.6% of phenotypic variation, respectively. Compared with previous studies, QYr.AYH-5BL may be a new QTL, whereas QYr.AYH-7DS may be Yr18. Haplotype analysis revealed that QYr.AYH-5BL is probably present in 6.2% of the 323 surveyed Chinese wheat landraces. The kompetitive allele specific PCR (KASP) markers for QYr.AYH-5BL were developed by the linked SNP markers to successfully confirm the effects of the QTL in a validation population derived from a residual heterozygous line and were further assessed in 38 Chinese wheat landraces and 92 cultivars. Our results indicated that QYr.AYH-5BL with linked KASP markers has potential value for marker-assisted selection to improve stripe rust resistance in breeding programs.

Stripe rust (yellow rust), caused by Puccinia striiformis f. sp. tritici, is one of the most destructive diseases of wheat worldwide. Chinese wheat landrace Guangtoumai (GTM) exhibited a high level of resistance against predominant P. striiformis f. sp. tritici races in China at the adult plant stage. The objective of this research was to identify and map the major locus/loci for stripe rust resistance in GTM. A set of 212 recombinant inbred lines (RILs) was developed from a cross between GTM and Avocet S. The parents and RILs were evaluated in three field tests (2018, 2019, and 2020 at Chongzhou, Sichuan) with the currently predominant P. striiformis f. sp. tritici races for final disease severity and genotyped with the Wheat 55K single nucleotide polymorphism (SNP) array to construct a genetic map with 1,031 SNP markers. A major locus, named QYr.GTM-5DL, was detected on chromosome 5DL in GTM. The locus was mapped in a 2.75-cM interval flanked by SNP markers AX-109855976 and AX-109453419, explaining up to 44.4% of the total phenotypic variation. Since no known Yr genes have been reported on chromosome 5DL, QYr.GTM-5DL is very likely a novel adult plant resistance locus. Haplotype analysis revealed that the resistance allele displayed enhanced levels of stripe rust resistance and is likely present in 5.3% of the 247 surveyed Chinese wheat landraces. The derived cleaved amplified polymorphic sequence (dCAPS) marker dCAPS-5722, converted from a SNP marker tightly linked to QYr.GTM-5DL with 0.3 cM, was validated on a subset of RILs and 48 commercial wheat cultivars developed in Sichuan. The results indicated that QYr.GTM-5DL with its linked dCAPS marker could be used in marker-assisted selection to improve stripe rust resistance in breeding programs, and this quantitative trait locus will provide new and possibly durable resistance to stripe rust.