EVALUATION OF TRICHODERMA SPP. AS BIOCONTROL AGENTS AGAINST FUSARIUM HEAD BLIGHT OF WHEAT

Author

• Halil POLAT, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2026

Degree Name

Doctor of Philosophy

Department

Agricultural Sciences

First Advisor

Fakhoury, Ahmad

Abstract

Wheat is extensively influenced by biotic pressures, such as pests and diseases. Pathogens, such as fungi, viruses, and bacteria, may be responsible for an average global decrease of 21.5% in wheat yield among biotic stressors. Fusarium Head Blight (FHB) has been called the most devastating wheat disease in the USA, resulting in a total loss of 17 billion U.S. dollars from 1993 to 2014. Fusarium graminearum, a member of the Fusarium graminearum species complex (FGSC), primarily causes FHB in wheat in the United States. Significant FHB outbreaks have occurred in various regions of the United States throughout each decade since the disease was first characterized by W. G. Smith in 1884. The economic and social impact of FHB worldwide have a profound effect due to the losses reaching billions of dollars because of yield reductions and mycotoxin contamination. The findings of this study indicate that the application of fungal biological control agents may be a powerful tool for managing FHB development in wheat production. The use of Trichoderma species as biocontrol agents demonstrated their efficiency to inhibit the development of F. graminearum and mycotoxin accumulation under field and greenhouse conditions. The development of an effective biocontrol program for managing FHB relies on understanding the biological mechanisms that take part in the interaction between biological control agents and F. graminearum. Thus, this research examined the Volatile Organic Compounds (VOCs) emitted during interaction between the two fungi to characterize volatilomes and to identify VOCs involved in antagonism as part of biological control and to detect the temporal shifts in VOC during confrontation. In addition, a dual RNA-seq experiment was conducted to uncover transcriptomic shifts in Trichoderma species and Pathogen to understand molecular mechanisms underlying antagonistic interactions. The transcriptomic analysis revealed that those significant shifts were discovered during 1-4 and 7 days of confrontation of both fungi. Therefore, these findings contribute to the developing biological control program aimed at managing F. graminearum and inhibiting mycotoxin production in wheat. Moreover, they offer insights that may contribute to the management of other plant fungal diseases.