By Silvina Arias, Adjunct Assistant Professor Plant Pathology, Entomology and Microbiology, ISU

Project Collaborator:

• Jamie O’Rourke, Research Geneticist, Agronomy

Project Summary

Iron deficiency chlorosis (IDC) is the symptom typically observed in soybean growing in high-pH soils with high carbonate concentrations where iron availability is reduced. Currently, the most important management option is the selection of ID-resistant cultivars. Several studies have detected QTL that confers resistance to IDC.

Other limitations on soybean production are due to soybean diseases that reduce yield. Several species of Fusarium are well recognized as soybean pathogens, such as F. virguliforme, the causal agent of sudden death syndrome (SDS), F.  oxysporum causing Fusarium wilt or F. graminearum, a major necrotrophic pathogen causing severe root rot. F. graminearum also is the most frequently recovered species of Fusarium in fields in Iowa. Management of soil-borne diseases like Fusarium root rot depends mainly on genetic resistance or seed treatments during emergence and the seedling stages. Soybean resistance to F. graminearum was described in the soybean cultivar Conrad, and putative Quantitative Trait Loci (QTL) associated with resistance to F. graminearum.

Although soybean plants with IDC symptoms often display Fusarium root rot symptoms, currently the basis of this association is not clear. In general, research programs focus on identifying resistance to a particular stress and do not test susceptibility to other biotic or abiotic stresses. Consequently, improved varieties may respond unpredictably when grown in field conditions.

The objective of this study is to characterize soybean genes that are differentially regulated by the host during F. graminearum infection in an iron deficiency environment in order to identify new potential resistant mechanisms and candidate genes involved in the defense response. 

(1-year project funded fall 2023)