Fusarium head blight (FHB) is a devastating fungal disease caused by Fusarium graminearum. Pectin lyase, a pectinase, acts on the α-1,4-glycosidic linkage of galacturonic acid primarily by β-elimination. In this study, three pectin lyase genes (FgPel1, 2, 3) in F. graminearum were selected, and deletion mutants (ΔFgPel1, 2, 3) were constructed by homologous recombination for functional characterization. The gene deletions affected the morphology and growth rate of F. graminearum on pectin medium at various concentrations, with the growth rate of ΔFgPel1 being more significant. The growth of ΔFgPel1 colonies slowed at pH 4, with optimal growth at pH 6.5, whereas ΔFgPel2 and ΔFgPel3 exhibited greater inhibition at pH 8. Colony morphology and diameter of the deletion mutants showed no significant differences compared to the wild-type strain PH-1, and there was no effect on conidial production or germination rate. Pathogenicity assays demonstrated that gene deletion significantly reduced the ability of F. graminearum to infest corn silks and wheat ears, and that ΔFgPel2 showed a more pronounced reduction in pathogenicity on wheat spikes. In summary, the pectin lyase genes (FgPel1, 2, 3) are involved in pectin utilization and are influenced by external pH conditions, which attenuate the pathogenicity of F. graminearum without affecting its vegetative growth or asexual spore formation. These findings elucidate the roles of these genes and provide a basis for controlling FHB.

Glutaredoxins (GRXs) are widely distributed oxidoreductase enzymes that play important roles in plant growth, development, and responses to various stresses. In this study, bioinformatics methods were used to identify and analyze the wheat GRX gene family and predict their properties and potential functions. RNA-seq and RT-qPCR expression analyses were used to investigate their regulatory functions under hormone treatment and fungal diseases. In this study, 86 GRX genes were identified in wheat and classified into CC-type, CGFS-type, and CPYC-type categories with no TaGRX located on chromosome 4B. The results show that TaGRXs regulate wheat transcriptional responses and have an integrative role in biotic and abiotic stress responses. TaGRXs are involved in wheat responses to Fusarium graminearum, Puccinia striiformis, and Erysiphe graminis diseases. TaGRX73-7D, TaGRX20-3A, and TaGRX29-3B play a negative regulatory role in E. graminis infection but a positive regulatory role in F. graminearum and P. striiformis infection. These TaGRXs play potential regulatory functions in wheat responses to the plant hormones and signaling molecules, including IAA, ABA, H₂O₂, and SA. The findings of this study lay the groundwork for further investigation of the functions of wheat GRX genes and their potential use as candidate genes for molecular breeding of stress-resistant wheat varieties.

Context: Wheat (Triticum aestivum L.) is one of the world’s most vital food crops. Drought stress is a significant physiological challenge for wheat, leading to reduced productivity. As a polygenic stress, drought poses one of the major threats to crop yields in agriculture. Aim: Advances in sequencing technology have shown that long non-coding RNAs (lncRNAs) play important roles in plant growth and stress responses. Methods: This study analyzed 11 RNA-seq datasets from wheat subjected to drought treatment over various time points. Functional enrichment annotation and quantitative reverse transcription polymerase chain reaction (RT-qPCR) analyses were employed to explore the regulatory responses of lincRNAs during drought stress. Key results: The results identified 740 candidate lincRNAs, which were found to be shorter and have fewer exons compared to mRNAs. Differential expression analysis revealed 310 differentially expressed lincRNAs (DE-lincRNAs) responsive to drought stress. Conclusions: Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the lincRNAs and their target mRNAs were enriched in terms and pathways associated with photosystems and photosynthesis. Expression analysis demonstrated a positive correlation between lincRNA expression levels and those of their target genes, suggesting their potential involvement in regulating drought stress in wheat. Implications: The findings of this study lay the groundwork for future research on the regulatory mechanisms of lincRNAs in wheat stress responses, which is important for the breeding of drought-resistant wheat varieties.

Fusarium head blight caused by Fusarium graminearum is a serious fungal disease on wheat and maize worldwide, resulting in a significant economic loss. DUG3-mediated glutathione utilization has been revealed to play important roles in fungal differentiation, metabolism, stress adaptation, and plant infection. However, functional roles of the DUG3 homolog in F. graminearum remain uncharacterized. In the present study, FgDUG3 was knocked-out via homologous recombination to investigate functions of this gene. The deletion mutant (ΔFgDUG3) was normal in mycelial growth, but showed impairments in conidiation, conidial germination, and plant infection, compared to the wild-type strain. The defects of ΔFgDUG3 were recovered in the complemented strain (ΔFgDUG3-C). Transcriptomic analysis revealed that deletion of FgDUG3 caused significantly differential expression of genes, mainly related to metabolism, catabolism, cellular structure organization, and signal transduction. Taken together, these results suggest that FgDUG3 plays important roles in the differentiation and pathogenicity of F. graminearum.