Location: Cereal Crops Improvement Research
Project Number: 3060-21000-046-037-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 31, 2024
End Date: Aug 30, 2026
Objective:
1) Develop transgenic barley plants expressing FHB resistance genes; and 2) score disease response of transgenic plants in FHB nursery field.
Approach:
FHB1, a QTL in the Chinese wheat variety Sumai3, confers durable and broad-spectrum resistance to Fusarium species, and it has been extensively used as the best source of FHB resistance in wheat. The recent breakthrough on FHB research is that the FHB1 gene has been successfully cloned and functionally characterized in wheat. It was revealed that the FHB1, encoding a putative histidine-rich calcium-binding protein (TaHRC), is probably required for disease susceptibility. Isolation of this major QTL provides novel perspective to control this devastating disease, and FHB immunity may be achieved by manipulation of the FHB1 orthologs in other species. Therefore, knocking out of the barley ortholog of FHB1 may disrupt FHB susceptibility for this species. BLAST searches showed that the barley ortholog HvHRC is a single copy gene and resides within the genomic region syntenic to the wheat FHB1 locus. To characterize the Fhb1 ortholog and determine if this gene is also required for FHB susceptibility in barley, we will use the CRISPR technology to knock out the HvHRC gene in barley cv Conlon. Homozygous knockouts have been obtained. Disease levels in the derived knockout mutants will be investigated in UMN nursery.
Another major FHB resistance gene cloned is FHB7 encodes glutathione S-transferase detoxifying the trichothecene toxin. and, when expressed in wheat, confers resistance to FHB. Thus, Fhb7 resistance is different from Fhb1 resistance, although both are notable for durable resistance. Sequence homologies between fungal and plant Fhb7 suggested that this gene may be horizontally transferred from an Epichloë species that establishes symbiosis with grasses. The homozygous T1 plants overexpressing FHB7 or driven by the native promoter have been obtained. FHB severity will be also assessed under filed conditions in a randomized complete block with three replicates. After counting the number of infected spikelets from at least 50 spikes for both wild type and transgenic, the severity will be expressed as a percentage of the total spikelets checked.
