Semester of Graduation

Summer, 2026

Degree

Master of Science (MS)

Department

Department of Plant Pathology and Crop Physiology

Document Type

Thesis

Abstract

Bacterial panicle blight (BPB), caused by Burkholderia glumae, is a major rice disease with limited management options and limited sources of strong resistance. This study characterized BPB resistance using QTL mapping in a defense-primed Jupiter × Bengal recombinant inbred line population and transcriptomic analysis of the BPB-resistant line LM1 and susceptible cultivar Lemont. A total of 164 RILs were evaluated for BPB response under defense-primed field conditions following seed treatment with an avirulent strain of B. glumae. Disease severity showed continuous variation across the population, confirming the quantitative nature of BPB resistance. QTL mapping identified resistance-associated regions on chromosome 4. qBPB4.1 was detected in 2021 and in the combined mean analysis, while qBPB4.2 was detected in 2023. These QTLs explained 8.06% to 16.23% of the phenotypic variation. This region including both loci was located near a previously reported BPB resistance-associated QTL in the same population under non-primed conditions, but the QTL detected in this study showed a greater estimated effect. Candidate genes within this region included genes associated with transcriptional regulation, receptor-like kinase signaling, reactive oxygen species metabolism, and protein regulation. RNA-seq analysis showed that the strongest transcriptional difference between LM1 and Lemont occurred at 6 hours post inoculation. LM1 showed stronger early activation of genes related to cellular development, secondary metabolism, and cell death, while Lemont showed a weaker and delayed response. WGCNA identified a module strongly associated with the early LM1 response, suggesting coordinated regulation of defense-related genes. Collectively, these results provide valuable genetic and transcriptomic targets for future breeding, fine mapping, and functional validation to support the development of rice cultivars with improved BPB resistance and greater disease resilience.

Date

7-16-2026

Committee Chair

Ham, Jong Hyun

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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Available for download on Friday, July 16, 2027

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