Prof. Dr. Ian T. Baldwin
Microbial mediation of plant-herbivore interactions

Abstract
For the past two decades, my group has been studying plant-herbivore, plant-pollinator, and plant-fungal interactions in the model plant ecological expression system, Nicotiana attenuata. We are now beginning to explore how these interactions can be modified by microbial players. For these studies, we have at our disposal a large collection of transformed plants, silenced in various components of their signaling, recognition or down-stream defense responses, microarray, proteomic and metabolomic analytical platforms to analyze the interactions. We are particularly interested in exploring the three following systems, but are open to other ideas as well:
1) The role of bacteria in the nectar of Nicotiana attenuata nectar. Nectar plays an important role in mediating gene flow in this species and the nectar contains a number of secondary metabolites and ROS (reactive oxygen species) producing proteins that dramatically alter the rate with which nectar is utilized by flower visitors. Given that sugar solutions will rapidly ferment at the high temperatures in which this plant normally grows, anti-microbial functions are clearly important. This project would involve characterize bacterial communities that colonize the nectar of plants with and without these secondary metabolites and ROS producing proteins to better understand how pollinator interactions are influenced by the sterility of the nectar.
2) Plant growth promoting rhizobacteria are well described in many systems and we have characterized the community of rhizobacteria that influence plant growth and germination in N. attenuata. This project would continue the analysis of isolates which influence growth, but do so without influencing the well characterized ethylene and auxin signaling systems.
3) Thorns, prickles and spines are a common form of mechanical defense amongst many of the plant species that inhabit the Great Basin Desert. It has been suggested that the effectiveness of this form of mechanical defense can be augmented by the colonization of these sharp protuberances by pathogenic bacteria, which can be interjected into wounds and significantly disable herbivores. This project would involve characterizing the bacterial communities on these protuberances and manipulate their occurrence to see if they alter the effectiveness of these mechanical defenses.
 

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