Abiotic stresses are major constraints limiting crop growth and production. Heat shock factors (Hsfs) play significant roles in mediating plant resistance to various environmental stresses, including heat, drought and salinity. In this study, we explored the biological functions and underlying mechanisms of wheat TaHsfA6f in plant tolerance to various abiotic stresses. Gene expression profiles showed that TaHsfA6f has relatively high expression levels in wheat leaves at the reproductive stage. Transcript levels of TaHsfA6f were substantially up-regulated by heat, dehydration, salinity, low temperature, and multiple phytohormones, but was not induced by brassinosteroids (BR). Subcellular localization analyses revealed that TaHsfA6f is localized to the nucleus. Overexpression of the TaHsfA6f gene in Arabidopsis results in improved tolerance to heat, drought and salt stresses, enhanced sensitivity to exogenous abscisic acid (ABA), and increased accumulation of ABA. Furthermore, RNA-sequencing data demonstrated that TaHsfA6f functions through up-regulation of a number of genes involved in ABA metabolism and signaling, and other stress-associated genes. Collectively, these results provide evidence that TaHsfA6f participates in the regulation of multiple abiotic stresses, and that TaHsfA6f could serve as a valuable gene for genetic modification of crop abiotic stress tolerance.

Wheat powdery mildew is one of the most destructive diseases threatening global wheat production. The wild relatives of wheat constitute rich sources of diversity for powdery mildew resistance. Here, we report the map-based cloning of the powdery mildew resistance gene Pm13 from the wild wheat species Aegilops longissima. Pm13 encodes a mixed lineage kinase domain-like (MLKL) protein that contains an N-terminal-domain of MLKL (MLKL_NTD) domain in its N-terminus and a C-terminal serine/threonine kinase (STK) domain. The resistance function of Pm13 is validated by mutagenesis, gene silencing, transgenic assay, and allelic association analyses. The development of introgression lines with significantly reduced chromosome segments of Ae. longissima encompassing Pm13 enables widespread deployment of this gene into wheat cultivars. The cloning of Pm13 may provide valuable insights into the molecular mechanisms underlying Pm13-mediated powdery mildew resistance and highlight the important roles of kinase fusion proteins (KFPs) in wheat immunity.

Powdery mildew is a devastating disease that affects wheat yield and quality. Wheat wild relatives represent valuable sources of disease resistance genes. Cloning and characterization of these genes will facilitate their incorporation into wheat breeding programs. Here, we report the cloning of Pm57, a wheat powdery mildew resistance gene from Aegilops searsii. It encodes a tandem kinase protein with putative kinase-pseudokinase domains followed by a von Willebrand factor A domain (WTK-vWA), being ortholog of Lr9 that mediates wheat leaf rust resistance. The resistance function of Pm57 is validated via independent mutants, gene silencing, and transgenic assays. Stable Pm57 transgenic wheat lines and introgression lines exhibit high levels of all-stage resistance to diverse isolates of the Bgt fungus, and no negative impacts on agronomic parameters are observed in our experimental set-up. Our findings highlight the emerging role of kinase fusion proteins in plant disease resistance and provide a valuable gene for wheat breeding.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), reduces wheat yields and grain quality, thus posing a significant threat to global food security. Wild relatives of wheat serve as valuable resources for resistance to powdery mildew. Here, the powdery mildew resistance gene Pm6Sl is cloned from the wild wheat species Aegilops longissima. It encodes a nucleotide-binding leucine-rich repeat (NLR) protein featuring a CC-BED module formed by a zinc finger BED (Znf-BED) domain integrated into the coiled-coil (CC) domain. The function of Pm6Sl is validated via mutagenesis, gene silencing, and transgenic assays. In addition, we develop a resistant germplasm harbouring Pm6Sl in a very small segment with no linkage drag along with the diagnostic gene marker pm6sl-1 to facilitate Pm6Sl deployment in wheat breeding programs. The cloning of Pm6Sl, a resistance gene with BED-NLR architecture, will increase our understanding of the molecular mechanisms underlying BED-NLR-mediated resistance to various pathogens.

Environmental stresses, especially heat and drought, severely limit plant growth and negatively affect wheat yield and quality worldwide. Heat shock factors (Hsfs) play a central role in regulating plant responses to various stresses. In this study, the wheat heat shock factor gene TaHsfA2e-5D on chromosome 5D was isolated and functionally characterized, with the goal of investigating its role in responses to heat and drought stresses. Gene expression profiling showed that TaHsfA2e-5D was expressed constitutively in various wheat tissues, most highly in roots at the reproductive stage. The expression of TaHsfA2e-5D was highly up-regulated in wheat seedlings by heat, cold, drought, high salinity, and multiple phytohormones. The TaHsfA2e-5D protein was localized in the nucleus and showed a transcriptional activation activity. Ectopic expression of the TaHsfA2e-5D in yeast exhibited improved thermotolerance. Overexpression of the TaHsfA2e-5D in Arabidopsis results in enhanced tolerance to heat and drought stresses. Furthermore, RT-qPCR analyses revealed that TaHsfA2e-5D functions through increasing the expression of Hsp genes and other stress-related genes, including APX2 and GolS1. Collectively, these results suggest that TaHsfA2e-5D functions as a positive regulator of plants’ responses to heat and drought stresses, which may be of great significance for understanding and improving environmental stress tolerance in crops.