Hongya Wu

Strigolactones (SLs), a novel class of plant hormones, play a crucial role in plant growth and development. SMXL (SUPPRESSOR OF MAX2 1-like) is a key gene in the SL signaling pathway, regulating its function by inhibiting the reception of SL signals. Therefore, investigating how SMXL regulates SL to influence wheat growth, development, and stress resistance is of significant importance. In this study, 22 SMXL genes were identified in the Chinese Spring wheat reference genome. Bioinformatics analysis revealed that these genes belong to the Group II subfamily, exhibiting similar physicochemical properties and conserved motifs. Ka/Ks analysis indicated that these genes have undergone purifying selection during evolution. Cis-acting element analysis showed that the promoter regions of TaSMXL genes are enriched with light-responsive elements and regulatory elements related to growth, development, and stress responses. Expression pattern analysis demonstrated that TaSMXL genes exhibit significant differential expression under drought, salt, and cold stress conditions, revealing the potential molecular mechanisms of wheat’s response to multiple abiotic stresses. This study provides a theoretical foundation for understanding the functional roles of SMXL genes in wheat and offers valuable candidate gene resources for breeding stress-resistant wheat varieties.

Chromosomal recombination is a pivotal biological mechanism for generating novel genetic diversity, essential for plant breeding and genetic research endeavors. This study investigated the genetic loci involved in chromosomal recombination through analyzing five published recombinant inbred line (RIL) populations and four double haploid (DH) populations. Great phenotypic variations in recombination frequency were observed between populations and chromosomes. A total of 29 QTL were mapped, which were predominantly located on the B genome. Notably, one QTL on chromosome 6AL was identified from two RIL populations and one QTL on chromosome 3B was identified in both RIL and DH populations. Additionally, a map delineating recombination hotspot regions was developed, and these regions were observed on all chromosomes except for 6B. Recombination hotspot regions tended to locate on chromosomes 1D, 3A, 3B, 6A, and 7D compared to chromosomes 1B, 5B, and 6B. In addition, most hotspot regions were located at chromosome termini, with some clustering in specific regions. Besides genetic factors, the study also explored the impact of chip size and population type on the number of identifiable chromosomal recombination events. Overall, this work improves our understanding of the molecular mechanisms for the chromosomal recombination rate and may contribute to the optimization of breeding strategies in wheat.

Weak-gluten wheat is the main raw material for crisp and soft foods such as cookies, cakes, and steamed breads in China. However, it remains challenging to find an appropriate fertilization regime to balance the yield and quality of wheat for special uses (such as cookie making). Here, four nitrogen (N) fertilizer treatments were compared in terms of effects on the yield-, grain-, flour-, and dough-related traits and cookie quality of nine weak-gluten wheat varieties. Compared with other treatments, the treatment M (which had 180 kg ha⁻¹ N fertilizers with basal fertilizer:tillering fertilizer:jointing fertilizer = 5:1:4) was a superior fertilization strategy as it could ensure a higher yield (4.46 kg block⁻¹) and proper traits related to cookie quality. Moreover, environmental conditions and wheat genotypes exhibited significant effects on many quality-related traits. The quality of Chinese crisp biscuits showed a significant association with unit weight, redness, and solvent retention capacity in lactic acid solution, while that of American cookies was influenced by thousand-grain weight, hardness, rate of yield flour, and formation time as indicated by the Mantel test. Additional Pearson correlation analysis demonstrated that thousand-grain weight, hardness, and rate of yield flour can affect the quality of American cookies. Our findings demonstrate that it is necessary to comprehensively consider local conditions, variety selection, and optimal fertilization to achieve high-quality weak-gluten wheat for cookie making.