A.B., Biology, University of Chicago
Ph.D., Zoology, University of Washington
General Research Themes
The goal of the Schultz-Appel Chemical Ecology Laboratory (http://schultz-appel.missouri.edu/) is to explain patterns we see in nature by their underlying mechanisms. This requires a multidisciplinary approach including ecology, biochemistry, and molecular biology. Our research is not system-driven and we select systems on the basis of their utility in answering questions. We currently are focusing on herbivory in Arabidopsis and poplar because of the genetic advantages for gene-expression work. As access to tools and information grows, we hope to be able to support more projects on non-model organisms. We generally aim to take what we see outdoors into the lab to test hypotheses about causal factors under controlled conditions, then take what we learn back into the field to see if we're right.
Our current research has several major themes:
First, we are interested in interactions between plants and their insect herbivores. Because these interactions are strongly influenced by plant chemistry, we have developed a strong focus on natural products chemistry, especially phenolics and glucosinolates, including their activities, regulation of their synthesis, and their ecological significance in a wide range of environmental settings. We have developed a strong plant chemistry analysis lab, provide analyses on a collaborative basis with other researchers, and host students and visiting scientists to learn methods.
Second, we are interested in dynamic "induced" responses by plants to attack by insects, which are likely to be more important ecologically and evolutionarily than are constitutive traits. Issues we address include how plants perceive and identify attackers, how systemic responses are coordinated by the plant, constraints on dynamic responses, and the community and ecosystem impacts. We approach this with measures of defensive chemistry the expression of genes required for their synthesis.
Third, we want to know how some insects mask their attack or even manipulate plant defenses; this has led to an interest in the congruence between plants and animals in chemical signaling cascades and mechanisms. We work with the biochemical signals that may be involved in these interactions, including plant hormones, plant sensory systems, and insect secretions.
Fourth, we take a multitrophic point of view to understand know how plant responses to insect herbivores influences their responses to other stresses. We want to know how the influences of plant chemistry and plant responses cascade upward and downward through the ecosystem. This interest includes understanding how overlapping plant responses to multiple stimuli (e.g., microbes and various insects) may influence pest community structure, as one species influences another via hostplant changes. We are interested in whether responses to the physical environment (light, touch, soils) can influence plant defenses, altering the performance of and interactions among microbes and herbivores. This work is important to successful integrated pest management.
Specific Research Projects Now Underway
Project 1. Chemical ecology of Arabidopsis and its pests
Project 2. Spatially-explicit responses to herbivores (Populus, Arabidopsis)
Project 3. Molecular and biochemical ecology of plant galls.
Mewis, I, H.M. Appel, A. Hom, R. Raina and J.C. Schultz. 2005. Major signaling pathways modulate Arabidopsis thaliana (L.) glucosinolate accumulation and response to both phloem feeding and chewing insects. Plant Physiology 138:1149-1162.
Mewis I; Tokuhisa J; Schultz JC; Appel HM; Ulrichs C; Gershenzon J. 2006. Gene expression and glucosinolate accumulation in Arabidopsis thaliana in response to generalist and specialist herbivores of different feeding guilds and the role of defense signaling pathways. Phytochemistry 67: 2450-2462.
Fine, P.V.A., Miller, Z., Mesones, I., Irazuzta, S., Appel, H.M., Stevens, M. H. H., Sääksjärvi, I., Schultz, J.C., and Coley, P.D. 2006. The growth-defense tradeoff and habitat specialization by plants in Amazonian forests. Ecology 87:S150-S162.
Jagadeeswaran G., S. Raina, B. R. Acharya, S. B. Maqbool, S. L. Mosher, H. M. Appel, J. C. Schultz, D. F. Klessig and R. Raina. 2007. Arabidopsis GH3-LIKE DEFENSE GENE 1 is required for accumulation of salicylic acid, activation of defense responses and resistance to Pseudomonas syringae. Plant J 51: 234-46.
Acharya BR, Raina S, Maqbool SB, Jagadeeswaran G, Mosher SL, Appel HM, Schultz JC, Klessig DF, Raina R. 2007. Overexpression of CRK13, an Arabidopsis cysteine-rich receptor-like kinase, results in enhanced resistance to Pseudomonas syringae. Plant J. 50: 488-99.
Frost, CJ, Appel, HM, Carlson, JE, De Moraes, CM, Mescher, MC, Schultz, JC. 2007. Within-plant signalling via volatiles overcomes vascular constraints on systemic signalling and primes responses against herbivores, Ecol. Letters 10: 490-498.
Engelberth J, Seidl-Adams I, Schultz JC, Tumlinson JH. 2007. Insect elicitors and exposure to green leafy volatiles differentially upregulate major octadecanoids and transcripts of 12-oxo phytodienoic acid reductases in Zea mays. Mol Plant-Microbe Interact. 20: 707-716.
Havens, Timothy C., James M. Keller, Erin MacNeal Rehrig, Heidi M. Appel, Mihail Popescu, Jack C. Schultz, and James C. Bezdek. 2008. Fuzzy Cluster Analysis of Bioinformatics Data Composed of Microarray Expression Data and Gene Ontology Annotations. Proceedings of NAFIPS2008 Conference.