A study of bacterial endophytes in barley under Fusarium Head Blight infection

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dc.contributor.authorWeerasinghe, Vinuri
dc.contributor.examiningcommitteeBadea, Ana (Plant Science)
dc.contributor.examiningcommitteeBakker, Matthew (Microbiology)
dc.contributor.supervisorFernando, Dilantha
dc.contributor.supervisorWijekoon, Champa
dc.date.accessioned2025-01-10T15:40:29Z
dc.date.available2025-01-10T15:40:29Z
dc.date.issued2024-12-12
dc.date.submitted2024-12-13T02:22:05Zen_US
dc.degree.disciplinePlant Science
dc.degree.levelMaster of Science (M.Sc.)
dc.description.abstractEndophytes are microorganisms that exist in the internal plant tissues without substantial harm to the host plant, and they are suggested to confer beneficial roles in promotion of plant growth and protection from phytopathogens. Fusarium Head Blight (FHB) is a devastating plant disease affecting cereal crops worldwide, predominantly caused by Fusarium graminearum. Barley production and subsequently the feed and malting industries can be severely affected by FHB as the pathogen may diminish both the yield and quality of grains. Apart from that, FHB may also influence the endophytic microbiome of barley, particularly in the infected tissues. In this study, we collected grains, stems and roots from cultivated and wild barley genotypes with varying resistance to FHB that were artificially infected with F. graminearum in the field. Plant samples from control plots (i.e., non-FHB-infected) were also obtained. Sampling was conducted at the booting (S1), mid-dough (S2) and physiological maturity (S3) stages of barley in 2021 and 2022. Source grains of 2021 field experiments were also incorporated for the analyses. The endophytic bacterial community profiles of grains of four cultivated barley genotypes sampled at S2 and S3 from FHB-infected and non-FHB-infected plots were analyzed by metabarcoding of the 16S rRNA gene. In addition to FHB, the effects on the microbiome from the sampling year, barley growth stage at sampling, and the barley genotype were tested. We observed a significant change in the overall bacterial endophytic community structure with FHB and the plant growth stage, but not with the barley genotype or the year of sampling. Seven bacterial taxa were significantly associated with FHB, plant growth stage and barley genotype. Further, bacteria that belong to 27 genera were shared among all three years, and 122 more genera were shared between 2021 and 2022, whereas very few genera were unique to a particular year. Moreover, bacterial endophytes were isolated from grains, stems and roots of cultivated and wild barley genotypes sampled at S1, S2 and S3 in 2022 from FHB-infected and non-FHB-infected field plots. They were characterized in vitro for the inhibition of seven pathogen species/chemotypes causing FHB, including F. graminearum. Species, mainly Serratia and Bacillus isolated from barley tissues inhibited the mycelial growth of FHB-causing pathogens up to 75%. Altogether, these findings demonstrate the importance of exploring bacterial endophytes in barley to understand the microbial shifts as well as to determine biological control agents for FHB.
dc.description.noteFebruary 2025
dc.description.sponsorshipEvolution of Fungal Pathogens (EvoFunPath) Fellowship University of Manitoba
dc.identifier.urihttp://hdl.handle.net/1993/38775
dc.language.isoeng
dc.rightsopen accessen_US
dc.subjectHordeum vulgare
dc.subjectmicrobiome
dc.subjectbacterial endophytes
dc.subjectFusarium head blight
dc.subjectdeoxynivalenol
dc.subjectmetabarcoding
dc.subjectantifungal properties
dc.titleA study of bacterial endophytes in barley under Fusarium Head Blight infection
dc.typemaster thesisen_US
local.subject.manitobayes
project.funder.nameAgriculture and Agri-Food Canada
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