The root of the problem: diverse vulnerability to xylem cavitation found within the root system of wheat plants

The propagation of xylem embolism throughout the root systems of drought-affected plants remains largely unknown, despite this process being comparatively well characterized in aboveground tissues. We used optical and X-ray imaging to capture xylem embolism propagation across the intact root systems of bread wheat (Triticum aestivum L. 'Krichauff') plants subjected to drying. Patterns in vulnerability to xylem cavitation were examined to investigate whether vulnerability may vary based on root size and placement across the entire root system. Individual plants exhibited similar mean whole root system vulnerabilities to xylem cavitation but showed enormous 6 MPa variation within their component roots (c. 50 roots per plant). Xylem cavitation typically initiated in the smallest, peripheral parts of the root system and moved inwards and upwards towards the root collar last, although this trend was highly variable. This pattern of xylem embolism spread likely results in the sacrifice of replaceable small roots while preserving function in larger, more costly central roots. A distinct pattern of embolism-spread belowground has implications for how we understand the impact of drought in the root system as a critical interface between plant and soil.

Analysis of sloppiness in model simulations: Unveiling parameter uncertainty when mathematical models are fitted to data

This work introduces a comprehensive approach to assess the sensitivity of model outputs to changes in parameter values, constrained by the combination of prior beliefs and data. This approach identifies stiff parameter combinations strongly affecting the quality of the model-data fit while simultaneously revealing which of these key parameter combinations are informed primarily by the data or are also substantively influenced by the priors. We focus on the very common context in complex systems where the amount and quality of data are low compared to the number of model parameters to be collectively estimated, and showcase the benefits of this technique for applications in biochemistry, ecology, and cardiac electrophysiology. We also show how stiff parameter combinations, once identified, uncover controlling mechanisms underlying the system being modeled and inform which of the model parameters need to be prioritized in future experiments for improved parameter inference from collective model-data fitting.

Plant-Based Vaccines: The Way Ahead?

Severe virus outbreaks are occurring more often and spreading faster and further than ever. Preparedness plans based on lessons learned from past epidemics can guide behavioral and pharmacological interventions to contain and treat emergent diseases. Although conventional biologics production systems can meet the pharmaceutical needs of a community at homeostasis, the COVID-19 pandemic has created an abrupt rise in demand for vaccines and therapeutics that highlight the gaps in this supply chain's ability to quickly develop and produce biologics in emergency situations given a short lead time. Considering the projected requirements for COVID-19 vaccines and the necessity for expedited large scale manufacture the capabilities of current biologics production systems should be surveyed to determine their applicability to pandemic preparedness. Plant-based biologics production systems have progressed to a state of commercial viability in the past 30 years with the capacity for production of complex, glycosylated, "mammalian compatible" molecules in a system with comparatively low production costs, high scalability, and production flexibility. Continued research drives the expansion of plant virus-based tools for harnessing the full production capacity from the plant biomass in transient systems. Here, we present an overview of vaccine production systems with a focus on plant-based production systems and their potential role as "first responders" in emergency pandemic situations.