No abstract

Analysis of the interaction of pathogens with plant roots is often complicated by the growth of plants in a soil substrate. A soil-free plant growth system (SPS) was developed that removes the need for a substrate while supporting the growth of seedlings in a nutrient rich, oxygenated environment. The model legume Lupinus angustifolius was used to compare the growth of seedlings within soil and the SPS. Seedlings grown under both conditions were similar in morphology, anatomy and health (measured by leaf chlorophyll abundance) and importantly there was little difference in root growth and development although straighter and fuller root systems were achieved in the SPS. The ease of access to the root system proved efficient for the analysis of root and pathogen interactions with no interference from soil or adhering particulate matter. Following inoculation of L. angustifolius roots with Phytophthora cinnamomi the host ⁄ pathogen interaction was easily observed and tissues sampled undamaged.

In order to discover phytochemicals that are potentially bioactive against Phytophthora cinnamomi, (a soilborne plant pathogen) a metabolite profiling protocol for investigation of metabolic changes in Lupinus angustifolius L. plant roots in response to pathogen challenge has been established. Analysis of the metabolic profiles from healthy and P. cinnamomi-inoculated root tissue with high resolution mass spectrometry and nuclear magnetic resonance spectroscopy confirmed that although susceptible, L. angustifolius upregulated a defence associated genistein and 2 0 -hydroxygenisteinbased isoflavonoid and a soyasapogenol saponin at 12 h post inoculation which increased in concentration at 72 h post inoculation. In contrast to the typical susceptible interaction, the application of a phosphorous-based treatment to L. angustifolius foliage 48 h before P. cinnamomi challenge negated the ability of the pathogen to colonise the root tissue and cause disease. Importantly, although the root profiles of water-treated and phosphite-treated plants post pathogen inoculation contained the same secondary metabolites, concentration variations were observed. Accumulation of secondary metabolites within the P. cinnamomi-inoculated plants confirms that pathogen ingress of the root interstitially occurs in phosphite-treated plants, confirming a direct mode of action against the pathogen upon breaching the root cells.Additional keywords: mass spectrometry, NMR, plant defence mechanisms, plant defense mechanisms, phosphite.

A STEM-based faculty in an Australian university leveraged online educational technology to help address student and academic concerns associated with team-based assessment. When engagement and contribution of all team members cannot be assured, team-based assessment can become an unfair and inaccurate measure of student competency. This case study explores the design and capacity of an online self and intra-team peer-assessment of teamwork strategy to measure student engagement and enable peers to hold each other accountable during team-based assessments. Analysis of student interactions across 39 subjects that implemented the strategy in 2020, revealed that an average of 94.4% of students completed the self and intra-team peer-assessment task when designed as part of a summative team-based assessment. The analysis also revealed that an average of 10.3% of students were held accountable by their peers, receiving feedback indicating their teamwork skills and behaviours were below the required minimum standard. Furthermore, the strategy was successfully implemented in cohorts ranging from seven to over 700 students, demonstrating scalability. Thus, this online self and intra-team peer-assessment strategy provided teaching teams with evidence of student engagement in a team-based assessment while also enabling students to hold each other accountable for contributing to the team task. Lastly, as the online strategy pairs with any discipline-specific team-based assessment, it provided the faculty with a method that could be used consistently across its schools to support management and engagement in team-based assessments.

No abstract