Document Type

Thesis - Open Access

Award Date

2023

Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

Gazala Ameen

Abstract

Fusarium head blight (FHB), commonly called scab is the most devastating disease of wheat and barley caused by the ascomycete fungus, Fusarium graminearum. FHB affects both the quality and quantity of cereal grains affecting the supply chain of the food and feed industry and the marketability of the produce. Barley (Hordeum vulgare L.) is among the several crop species most vulnerable to FHB infection. An estimated 25% of Spring barley grain production in the United States is used to make malted beverages such as beer. Malting barley is a relatively high-value crop with high demands regarding grain quality. FHB directly damages barley spikes affecting yield besides contamination with trichothecene mycotoxins like deoxynivalenol (DON), posing a food safety concern to maltsters and brewers. Even the best source of resistance in barley is still found to harbor DON content above the specifications of the brewing industry (< 0.5 ppm). Our research is an attempt to bridge this gap and identify resistant lines and sources of resistance to incorporate into the breeding programs. The first chapter comprises a review detailing the host as well as the pathogen aspects involved in the causal and establishment of the pathogen in causing the disease. It also provides insights into the role of secondary metabolites in pathogenicity due to Fusarium head blight (FHB) and the consequent employment of host defense machinery in resultant resistance responses. The host resistance strategies to overcome the dynamics of the pathogen are examined and summarized. The key findings from the FHB-Barley pathosystem are incorporated, offering a valuable scientific understanding of FHB in barley crops, and exploring opportunities for improved management strategies. The review identifies knowledge gaps in the FHB-Barley pathosystem and summarizes current strategies recommended for controlling FHB in the pre-and post-harvest phases of barley production. The second objective of our research is to identify the barley lines which offer resistance against FHB. This study focuses on the host-pathogen interaction addresses the growing concern and global priority for safe food supply. For this, Field trials were conducted against 29 lines and 32 lines in spring 2022 and 2023 respectively. The barley used for our screening studies are received from different breeding programs across the United States. The results suggest variability for FHB resistance in the germplasm in 2022 and 2023. The third objective of my research is to evaluate the fg isolates collected at different time points during the last decade and identify the genomic diversity in pathogen isolates that leads to changes in virulence, toxigenicity, and host adaptation. Twenty (20) fg isolates collected from 2012 to 2022 are sequenced through Illumina and the data is analyzed to track changes in the genes leading to diversity. Allelic Variations in the mycotoxin producing TRI gene cluster are reported in some of the isolates through this study.

Library of Congress Subject Headings

Barley -- Disease and pest resistance.
Fusarium diseases of plants.

Publisher

South Dakota State University

Download

Share

COinS
 

Rights Statement

In Copyright