Wenchen Qiao

Leaf rust (LR), caused by Puccinia triticina, is a major constraint to global wheat production. Identifying quantitative trait loci (QTLs), conferring adult-plant resistance (APR), and developing breeder-friendly markers are essential for durable disease control. In this study, a recombinant inbred line (RIL) population derived from Liang66-S × Hengmai28 was evaluated for leaf rust severity across four environments. Maximum disease severity (MDS) showed continuous variation and moderate to high correlations among environments, indicating polygenic inheritance. Five APR QTLs were mapped on chromosomes 2BL, 3BS, 3BL, 7BL and 7DL, explaining 4.5–9.8% of the phenotypic variance (PVE) with LOD scores of 2.9–7.9. Among these, QLr.DFI-2BL, QLr.DFI-3BS, and QLr.DFI-7BL correspond to previously reported APR loci, whereas QLr.DFI-3BL and QLr.DFI-7DL represent potentially novel loci. QLr.DFI-3BL was detected across all four environments, while QLr.DFI-3BS and QLr.DFI-7BL showed the highest R² (7.7–8.5% and 8.4–9.8%). Multiple defense-related genes within the QTL intervals for LR were identified, including the putative NBS-LRR, the putative BTB/POZ-MATH, F-box, receptor-like kinase, polyphenol oxidase, calcium-dependent protein kinase, peroxidase, and ethylene-responsive transcription factors. Based on the flanking markers, five KASP markers were developed. K-LR-3BS (for QLr.DFI-3BS) and K-LR-7BL (for QLr.DFI-7BL) successfully genotyped a natural population with 120 accessions, with call rates of 100% and 94.2%, and showed significant association with reduced leaf rust severity. However, further validation in diverse genetic backgrounds and populations is required before they can be considered for routine marker-assisted selection. These results provide two KASP markers as promising markers that require further validation in diverse backgrounds and highlight QLr.DFI-3BS and QLr.DFI-7BL as promising targets for fine mapping and eventual cloning of APR genes in wheat.

Background: Heat stress (HS) during the grain-filling stage severely threatens wheat yield. While long non-coding RNAs (lncRNAs) are known to regulate plant stress responses, their specific roles in wheat grain filling under HS remain poorly understood. Results: In this study, we integrated population-scale transcriptomics to explore lncRNA-associated thermotolerance networks. Analysis of 41 diverse wheat genotypes under control and HS conditions identified 9,463 high-confidence lncRNA loci and thousands of differentially expressed transcripts. Weighted gene co-expression network analysis (WGCNA) uncovered modules closely linked to thousand-grain weight (TGW), highlighting 79 hub lncRNAs. Association analysis revealed 22 lncRNAs with haplotypes significantly correlated with TGW. Field phenotyping demonstrated that under HS, wheat genotypes the high expression of MSTRG.64082 exhibited significantly higher TGW than those with medium or low expression. A positive correlation between TGW and the expression level of MSTRG.64082 was also observed in the 2025 field trials. Furthermore, the heat-induced expression of MSTRG.64082 was accompanied by the specific upregulation of key heat-responsive genes. Genetic analysis indicated that MSTRG.64082 harbors a favorable haplotype (HapC) associated precisely with enhanced TGW under HS. Notably the HapC allele displays a temperature-associated latitudinal cline, with its frequency increasing significantly in warmer regions. These findings suggest that MSTRG.64082 potentially acts as a positive regulator of heat tolerance and may have been subjected to selection pressure in warm climates. Conclusions: This study provides a comprehensive population-level atlas of heat-responsive lncRNAs during wheat grain filling and highlights MSTRG.64082 as a promising candidate locus for breeding heat-tolerant wheat varieties.

At present, water shortage seriously affects wheat production in many parts of the world, and to solve this problem, water‐saving wheat breeding is an important research domain. The objective of this study was to evaluate water‐saving index (WSI), yield factors, and KASP (kompetitive allele specific polymerase chain reaction) markers in water‐saving wheat breeding carried out in Hengshui region, China. The result showed as follows: (1) The new index WSI could better indicate the water‐saving performance, including the yield potential and the stability of different wheat cultivars under water limited condition (WL). (2) Referring to the degree of heat stress (D) in that year, selecting one of the three yield factors as the focus will improve the breeding efficiency of water‐saving wheat cultivars. With the increase of the D within a certain range, high water‐saving wheat cultivars showed a high grain weight (GW) under WL. Meanwhile with the decreasing of D value, high water‐saving wheat cultivars showed high spike number under WL. (3) KASP aggregation breeding will significantly improve the efficiency of water‐saving breeding. The combination with the highest effective rate of selecting water‐saving varieties carried GS5‐2334‐SNP and Dreb_SNP favorable alleles, and GW2‐6B‐1709SNP, TaMoc‐2433, and 1fehw with adverse alleles, whereas GS5‐2334‐SNP and GW2‐6B‐1709SNP that related to GW were useful markers for water‐saving breeding. These results improved our knowledge on the usage of WSI, yield factors, and KASP markers on water‐saving wheat breeding.