Spring 2023

Moisture variations alter the formation and biological stability of mineral-associated organic matter

Dr. Jilling earned a B.Sc. degree in Agricultural and Environmental Science from McGill University in 2011. After working on a series of vegetable farms in Quebec, Connecticut and New Hampshire, she then conducted doctoral work at the University of New Hampshire as a member of Dr. Stuart Grandy’s research group. Dr. Jilling draws from soil biochemistry, ecology and mineralogy to inform our fundamental and practical understanding of soil fertility and soil health. Research and teaching efforts focus on soil organic matter dynamics and soil-plant-microbe interactions.

Implications of Space Platforms for Soil Research and Management on Earth

Morgan’s research interests are in understanding how biogeochemical cycles and feedbacks are initially established in regolith and degraded soils from Earth and other planetary bodies. Her PhD research specifically looks at soil organic matter stabilization, organo-mineral interactions, and microbiome dynamics in soil aggregates experiencing Earth gravity, microgravity, and different environmental stressors.

In tomato, resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) is determined by the immune receptor Prf, yet the mechanism by which transmission of the signal from Prf to downstream immune responses is largely unknown. We found that activated Prf interacts with and stabilizes the defense-related SlNAC1 transcription factor, which otherwise is highly unstable due to ubiquitin ligase SlSINA3-mediated ubiquitination. The activated Prf interfered with the ubiquitination of SlNAC1.  Particularly, the binding of activated Prf to SlNAC1 prevented SlNAC1 interaction with SlSINA3, thereby disrupting the SlSINA3-mediated ubiquitination of SlNAC1. Thus, our findings reveal a mechanism utilized by an NLR protein to activate immune signaling via manipulation of a defense-related transcription factor. 

New role of the plant vascular system to improve the crop yield

Application of nutrient fertilizers enables achievement of increased agricultural crop productivity. It has been important research programs to enhance nutrient use efficiency in crop species for permitting sustainable crop yield and, thereby ensure global food security under limited nutrient fertilizer input. During reduced mineral nutrient availability, plant roots are the first organs to recognize these stress conditions through root-localized mechanisms. These stresses can be converted into root-derived signals that are transported via the xylem for communicating these challenging conditions to the shoot. The root-derived signals, delivered into vegetative tissues, elicits generation of specific output signals that enter the phloem to transfer commands from the shoot to the root for integrating the demands for various developmental and physiological processes. Therefore, it has been proposed that the plant vascular system functions as an effective shoot-root communication route in mineral nutrient homeostasis. Recent studies have been discussed in the content of information macromolecules, including proteins and various forms of RNAs, in phloem, which function as mediators to integrate sophisticated regulatory networks between shoots and roots. It raised the question as to whether the phloem has evolved the delivery capacity of specific stress-signaling molecules for regulation of adaptive developmental responses when plants face mineral nutrient limitation. We will discuss the function of the phloem as an integrator to operate long-distance gene regulation for optimizing plant developmental and physiological processes under mineral nutrient-stress conditions, by delivering a cascade of signaling agents to various developing sink tissues.