Fusarium head blight (FHB), mainly caused by fungus Fusarium graminearum, is a devastating wheat disease worldwide, leading to reduced yield production and compromised grain quality due to contamination by mycotoxins, such as deoxynivalenol (DON). Manipulating the specific gene expression in microorganisms through RNA interference (RNAi) presents an opportunity for new-generation double-stranded RNA (dsRNA)-based formulations to combat a large number of plant diseases. Here, we applied both spray-induced gene silencing (SIGS) and host-induced gene silencing (HIGS) to target five virulence-related and DON-synthesized genes in F. graminearum, including protein kinase gene Gpmk1, zinc finger protein gene FgChy1, transcription factor FgSR, DON synthesis gene TRI5 and the cell-end marker protein gene FgTeaA, aiming to effectively control FHB in wheat. Direct spraying of individual or combined small interfering RNA (siRNAs) from the fungus showed reduced expression of target genes and suppressed pathogenic symptoms during F. graminearum infection in wheat leaves, with the combination of all five siRNAs demonstrating superior resistance. Furthermore, we generated transgenic wheat lines expressing chimeric RNAi cassettes targeting these five genes, and two independent lines exhibited strong resistance to FHB and Fusarium crown rot, and the reduced DON accumulation. Notably, the HIGS transgenic lines did not adversely impact plant growth and yield traits. Collectively, our findings support that SIGS and HIGS represent effective strategies targeting key pathogenic genes for bolstering disease resistance in crops.

In flowering plants, the inflorescence meristem (IM) provides founder cells to form successive floral meristems, which are precursors of fruits and seeds. The activity and developmental progression of IM are thus critical for yield production in seed crops. In some cereals, such as rice (Oryza sativa) and maize (Zea mays), the size of undifferentiated IM, which is located at the inflorescence apex, is positively associated with yield traits such as spikelet number. However, the relationship between IM size and yield-related spike traits remains unknown in the Triticeae tribe. Here we report that IM size has a negative correlation with yield traits in barley (Hordeum vulgare). Three FASCIATED EAR (FEA) orthologs, HvFEA2, HvFEA3, and HvFEA4, regulate IM size and spike morphogenesis and ultimately affect yield traits. Three HvFEAs genes are highly expressed in developing spikes, and all three loss-of-function mutants exhibit enlarged IM size, shortened spikes, and reduced spikelet number, which may lead to reduced grain yield. Natural variations identified in HvFEAs indicate selection events during barley domestication. We further reveal that HvFEA4, as a transcription factor, potentially targets multiple pathways during reproductive development, including transcriptional control, phytohormone signaling, and redox status. The roles of barley FEA genes in limiting IM size and promoting spikelet formation suggest the potential of increasing yield by manipulating IM activity.