The mission of the Crop Production and Pest Control Research Unit is to conduct research to minimize crop losses due to insects and pathogens and improve soybean quality. Specific projects are directed toward discovering the genetic, biochemical, and molecular mechanisms that confer insect resistance in cereals, disease resistance in grain crops and soybeans, and influence the chemical composition of soybean seeds. The information is applied to devise innovative strategies for insect and disease control and develop germplasm with improved quality traits, pest resistance, and agronomic characteristics.

Enhancing Soybean Pest Resistance

T. Scott Abney (Research Plant Pathologist) - The soybean pathology lab personnel consists of Wad Crochet and Brian Foss (ARS Technicians), David Smith (Graduate Student), Debra Hall and Caroline Logan (Purdue Technicians), and Scott Abney (ARS Research Plant Pathologist). The primary focus of the project is to identify and define the role(s) of fungal pathogens infecting soybeans. Host resistance is a major emphasis for Phytophthora root rot and sudden death syndrome. In order to evaluate soybean germplasm and breeding lines for disease resistance, a culture collection of soybean pathogens is maintained and utilized to identify and describe mycological and physiological characteristics of the biotypes associated with each disease. An additional activity involved in improving disease resistance and yield in soybeans is the project's responsibility for coordinating the Uniform Soybean Tests for the Northern Region.

Hessian Fly Resistance in Soft Winter Wheat

Brandon J. Schemerhorn (Research Entomologist) - Population biology of Hessian fly.

Richard H. Shukle (Research Entomologist) - Pervious phylogenetic studies in our lab have indicated Hessian fly populations from Israel were divergent compared to populations from North Africa, Europe, and North America. Our original culture of Israeli flies was lost through a chamber malfunction about a year ago. We have just received new shipments of Hessian fly from Israel and hope to establish robust cultures of populations from different regions of Israel. The Israeli flies will be used in a number of studies both in our lab as well as in Dr. Stuart’s lab at Purdue and in collaborations with Dr. Chen USDA-ARS at Manhattan, KS. Hopefully, this interaction with scientists in Israel will lead to future collaborations between ARS scientists at West Lafayette, IN and scientists with the Israeli Agricultural Ministry, Gilat, Israel.

Christie E. Williams (Research Molecular Biologist) - The general objective of Dr. Williams’ research, as specified by the USDA-ARS, is to broaden understanding of wheat resistance and susceptibility to the Hessian fly through the use of molecular genetics. Dr. Williams’ assigned research focus is on developing wheat molecular markers for use in marker-assisted breeding with new Hessian fly-resistance genes. Dr. Williams’ project plans focus on elucidating mechanisms of resistance and susceptibility in wheat responding to Hessian fly infestation. This innovative research, using cutting edge techniques such as quantitative real-time PCR, microarrays, functional proteomics and viral-induced gene silencing, has provided some of the first key insights into plant biochemical pathways and mechanisms leading to induced resistance and susceptibility against a non-chewing insect. Dr. Williams disproved the simplistic conjecture that the same mechanisms of resistance were used against microbes and insects by characterizing a highly specific and elegantly efficient response of wheat against Hessian fly larvae.

Manipulation of the Quality and Flavor of Soybean Proteins

Karen Kaczorowski (Research Molecular Biologist) - The goal of Dr. Kaczorowski’s research is to improve multiple aspects of soybean seed composition including protein and oil content. They will be using expression microarrays to characterize gene expression during soybean seed development in subdomains of the developing seed, as well as to identify genes that are regulated by diurnal cycles in developing soybean embryos. This will further our understanding of how these processes within the seed itself influence composition traits. They are focusing on studying the function, expression and effects on soybean seed of a number of transcription factors known to affect seed development in Arabidopsis. This translational research aims to study the effects of these regulatory genes on accumulation of seed storage proteins in order to develop biotechnology and conventional approaches to fine-tune soybean protein composition.
Soybean TILLInG
Dr. Kaczorowski’s lab is developing a chemically mutagenized TILLInG population that will allow us to study the function of genes that are required for normal soybean seed development. The population will allow us to take a reverse-genetic approach to determine what effect the loss of a given gene has on soybean seed development and composition.

Molecular and Genetic Mechanisms of Fungal Disease Resistance in Grain Crops

Larry D. Dunkle (Supervisory Research Plant Pathologist) - Research in the Corn and Sorghum Pathology Lab is focused on analyzing genes involved in light-regulated conidiation and secondary metabolism in the maize gray leaf spot pathogen, Cercospora zeae-maydis. Light conditions during growth and development of this fungus influence these two processes differentially. Blue light suppresses sporulation but promotes biosynthesis of the phytotoxin cercosporin, while red light has the opposite effects. Mutants disrupted in genes encoding putative blue-light receptors, cryptochrome (CRY-1) and white collar (CWC-1), have recently been obtained and phenotypically characterized. The other major project involves a microarray approach to analyze gene expression during gene-for-gene responses that determine the outcome of the interaction between maize and the northern leaf blight pathogen, Setosphaeria turcica. ARS post-doc Burt Bluhm and lab tech Corie Shaner do the real work!

Stephen B. Goodwin (Research Plant Pathologist) - Classical and molecular genetics of host-pathogen interactions between wheat and the Septoria tritici blotch pathogen, Mycosphaerella graminicola; Pathogen phylogenetics and speciation mechanisms; Genetic mapping and analysis of resistance genes; Gene expression during R-gene and non-host resistance responses of wheat and barley; Genomics.

Charles F. Crane (Geneticist - Bioinformatics) - Currently Dr. Crane is investigating cell-wall degrading enzyme loci and repetitive elements in the genomes of Mycosphaerella graminicola and Mycosphaerella fijiensis, which respectively cause destructive diseases of wheat and banana. He is also investigating the relationship of microsatellite motif frequency and codon usage in EST collections from 25 plant genera. All of this work is computational, and the microsatellite study involves extensive simulation of EST collections generated at random according to codon usage frequencies.

Molecular and Genetic Mechanisms of Resistance to Barley Yellow Dwarf Virus

Joseph M. Anderson (Research Molecular Biologist) - The primary focus Small Grain Virus-Host Interaction Laboratory is to identify and integrate into small grain germplasm, disease resistance traits with a primary focus on resistance to Barley and Cereal Yellow Dwarf viruses (YDV). The disease caused by this set of viruses has been particularly severe this year, reaching epidemic proportions in many parts of Indiana and surrounding states and resulting in significantly lower yields. This disease was the focus of an article in the May 25th issue of AgriNews Indiana. The good news is that through a collaborative project with the Purdue University small grains breeder, Dr. Ohm, wheat varieties have been developed that are highly resistant to these viruses. These lines are available for planting by wheat producers. We have determined that this host plant resistance blocks the virus from spreading from the initial site of infection by YDV-carrying aphids. In addition to analyzing the mechanism of this resistance, we have also developed a virus detection method which will determine if wheat leaf samples contain any of eight different viruses that infect wheat. This method was developed to determine which of these viruses are present in wheat fields. Understanding more about the virus diseases within a field and across a state such as Indiana will determine which viruses we need to have resistance to in future elite wheat lines. Our initial results show that wheat plants expressing virus disease symptoms typically contain two and as many as four different viruses. Producers and wheat scientists are very interested in this disease test and we are currently examining samples from many Indiana counties and research plots in West Lafayette, Indiana, Georgia and North Carolina.

Steven R. Scofield (Research Geneticist) - Our research program is focused on achieving two major objectives: increasing our understanding of the molecular signaling pathways that lead to the activation of defense pathways in plants, and applying this knowledge to improve disease resistance in cereal crops. Our work is carried out in collaboration with the other researchers of the USDA-ARS Crop Production and Pest Control Unit and the Small Grains Research Group, at Purdue, that study a range of agriculturally significant fungal, viral and insect diseases of cereals.

To achieve the first goal, our group has developed a high-throughput virus-induced gene silencing (VIGS) system to identify genes encoding functions required for disease resistance. We will then begin to investigate how the gene products function in resistance, and determine if they may be useful in achieving the second objective. Our VIGS system is based on barley stripe mosaic virus (BSMV) and has proven very useful in the analysis of disease resistance pathways in hexaploid wheat. Our work employing this system to identify genes required for leaf rust resistance in wheat was recently published (Scofield et. al., 2005).

Our approach to the second goal is to harness the power of naturally occurring disease resistance pathways, which are able to provide highly effective resistance to specific pathogens. These resistance systems have been used for decades to provide protection against particular “target” pathogens. Unfortunately, there are many significant pathogens for which no corresponding plant resistance systems are known. However, recent work demonstrates that some resistance pathways can, in fact, provide resistance to a broad-spectrum of “non-target” pathogens when they are engineered to be activated when the plant is attacked by “non-target” pathogens. To this end, we are using the tools of genetic engineering to test existing resistance pathways for the ability to provide defense against agriculturally important “non-target” pathogens, and developing strategies so that these pathways can be appropriated activated by these “non-target” pathogens.