Scholarly Work - Plant Sciences & Plant Pathology
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/8870
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Item Exopolysaccharide is required for motility, stress tolerance, and plant colonization by the endophytic bacterium Paraburkholderia phytofirmans PsJN(Frontiers Media SA, 2023-08) Fu, Benzhong; Yan, QingParaburkholderia phytofirmans PsJN is an endophytic bacterium and has been shown to promote the growth and health of many different plants. Exopolysaccharide (EPS) plays important roles in plant-bacteria interaction and tolerance to environmental stresses. However, the function of EPS in PsJN and its interaction with plants remain largely unknown. In this study, a deletion mutation of bceQ gene, encoding a putative flippase for the EPS biosynthesis, was introduced in the genome of PsJN. The ΔbceQ mutant produced a significantly lower level of EPS than the wild type strain in culture media. Compared to the wild type PsJN, the ΔbceQ mutant was more sensitive to desiccation, UV damage, salt (NaCl) and iron (FeCl3) stresses, and bacteriophage infection. More importantly, the mutation of bceQ decreased the endophytic colonization of PsJN in camelina (Camelina sativa) and pea (Camelina sativa) under plant drought stress conditions. To the best of our knowledge, this is the first report that EPS production is required for the maximal colonization of an endophytic bacterium in the plant tissues under stress conditions.Item Optimized High Throughput Ascochyta Blight Screening Protocols and Immunity to A. pisi in Pea(MDPI AG, 2023-03) Annan, Emmanuel N.; Nyamesorto, Bernard; Yan, Qing; McPhee, Kevin; Huang, LiAscochyta blight (AB) is a destructive disease of the field pea (Pisum sativum L.) caused by necrotrophic fungal pathogens known as the AB-disease complex. To identify resistant individuals to assist AB resistance breeding, low-cost, high throughput, and reliable protocols for AB screening are needed. We tested and optimized three protocols to determine the optimum type of pathogen inoculum, the optimal development stage for host inoculation, and the timing of inoculation for detached-leaf assays. We found that different plant development stages do not affect AB infection type on peas, but the timing of inoculation affects the infection type of detached leaves due to wound-induced host defense response. After screening nine pea cultivars, we discovered that cultivar Fallon was immune to A. pisi but not to A. pinodes or the mixture of the two species. Our findings suggest that AB screening can be done with any of the three protocols. A whole-plant inoculation assay is necessary for identifying resistance to stem/node infection. Pathogen inoculation must be completed within 1.5 h post-detachment to avoid false positives of resistance for detach-leaf assays. It is essential to use a purified single-species inoculum for resistant resource screenings to identify the host resistance to each single species.