|Jody Banks||Plant Molecular and Developmental Biology |
My research at Purdue focused on two questions. How is the fern Pteris vittata able to tolerate and hyperaccumulate arsenic in its fronds, and how is the sex of the Ceratopteris richardii gametophyte regulated?
|Leonor Boavida||Plant Cell and Developmental Biology|
Dr. Boavida’s lab investigates the cellular and molecular mechanisms that regulate one of the most impressive examples of cell-cell recognition in plant reproduction, the process of fertilization. Fertilization is defined by the fusion of two haploid sex cells or gametes, the sperm and egg which produce a diploid zygote that initiates a very sophisticated developmental program. But this definition does not capture the full scope of cellular events that evolved as a hallmark of flowering plants: the occurrence of two separate gametic fusions (double fertilization). In addition to the sperm-egg cell fusion, a second sperm fuse with a sister female gamete, the central cell to produce the endosperm whose function is to nurture the developing embryo within the seed. This means that flowering plants likely evolved a new signal transduction machinery to ensure a robust recognition between male and female gametes. However, for the majority of these signaling pathways, the function and the interactions of the molecular intermediates remain to be characterized. Our attention is currently focused on the function of Tetraspanins as scaffolding proteins, and other transmembrane partners that have been identified in the surface of plant gametes as potential mediators of gamete interactions. Our goal is to build a comprehensive “fertilization interactome” that will allow us not only to have a better understanding of gamete factors and signaling pathways controlling reproductive success, but also to quiz the network concerning evolutionary aspects of the fertilization process. The lab incorporates unique experimental tools in the research field using genetic, molecular, functional genomics and live cell imaging.
|Nicholas Carpita||Plant Cell Biology |
Dr. Nick Carpita’s research objectives are to characterize the structural and functional architecture of the plant cell wall, to understand the biochemical mechanisms of biosynthesis of its polysaccharides, and to identify the genes that encode the molecular machinery that synthesizes these components. Specific projects include identifying and characterizing cell wall mutants in Arabidopsis and maize by Fourier transform infrared spectra. Potential mutants identified by this novel spectroscopic method are characterized genetically to determine heritability. A systematic protocol was devised to use biochemical, cytological, and spectroscopic methods to characterize the function of cell-wall biogenesis-related genes in Arabidopsis and maize identified through the mutant screen. Dr. Carpita’s group is classifying mutants by artificial neural networks as a database to classify genes of unknown function. They also develop methods to investigate the biosynthesis and topology of cellulose and the mixed-linkage (1→3),(1→4)-β-D-glucan in maize. They use proteomic and immunological approaches to identify the catalytic machinery and its associated polypeptides. We have also begun a program to characterize the regulation by microRNAs and naturally occurring small interfering RNAs of cellulose synthases and suites of similarly regulated genes in networks that form primary and secondary walls. Finally, we desire to apply our knowledge of cell wall biology to solve practical problems in agriculture. Understanding wall composition and architecture and the regulation of the synthesis of its components is an essential tool in enhancing biomass quality and quantity for biofuel production.
|Zhixiang Chen||Molecular Plant-Pathogen Interactions |
Dr. Zhixiang Chen’s research interests are in two related areas of molecular plant stress responses. The first area concerns transcriptional regulation of plant responses to biotic and abiotic stresses. The second research area deals with protein quality control, trafficking and degradation pathways including autophagy and multivesicular bodies in plant stress responses.
|Peter Goldsbrough||Plant Molecular Biology |
Dr. Peter Goldsbrough’s research program is focused on two multigene families in Arabidopsis - metallothioneins (MTs) and glutathione S-transferases (GSTs). Metallothioneins are small metal binding proteins encoded by a small gene family. Recent studies with MT-deficient mutants indicates that MTs are involved in the accumulation of copper and zinc in various tissues including roots and shoots, and the redistribution of these metals during senescence and seed development. The primary reaction catalyzed by GSTs is conjugation of glutzthione to a toxic substrate. We have been studying how herbicide safeners induce the expression of GSTs and other components of the xenobiotic detoxification system, and how GSTs can be used to enhance herbicide tolerance in transgenic plants.
Dr. Goldsbrough is currently not accepting graduate students.
|Anjali Iyer-Pascuzzi||Plant Biology|
Dr. Iyer-Pascuzzi’s research investigates the mechanisms that plant roots use to perceive and respond to the environment. There are two primary areas of research in the lab. The first is focused on understanding the molecular basis of plant resistance to bacterial wilt, caused by Ralstonia solanacearum. Ralstonia is a devastating soil-borne pathogen that first infects root systems. Despite the devastation it causes, little is known regarding the networks that underlie resistance or susceptibility, and root responses to R. solanacearum are unclear. Using both tomato and Arabidopsis, we focus on understanding resistance responses at three levels of root development: root cell types, root developmental stages, and root architecture. Current questions include, what are the spatio-temporal dynamics of pathogen invasion in resistant and susceptible genotypes? How are different root cell types and developmental stages affected by bacterial wilt? What are the gene regulatory networks involved in the response to bacterial wilt within each cell type? We use a combination of cell biology, genetics, and genomics approaches to address these questions. The major goal of this research is to identify novel forms of resistance to bacterial wilt. Our second area of research is centered around the role of Nodule Inception-Like Proteins (NLPs) in root development. NLP proteins are a unique family of transcription factors found in a wide diversity of plant species. We are studying the molecular mechanisms through which these proteins mediate root development and stress responses in Arabidopsis.
|Gurmukh Johal||Molecular Pathology and Genetics|
Dr. Guri Johal’s interests and expertise are in maize pathology and genetics, and he is involved in three areas of research. The first concerns maize’s interaction with Cochliobolus carbonum, which causes a lethal leaf blight and ear mold disease. A key factor in this pathosystem is HC-toxin, a cyclic tetrapeptide, which is absolutely needed by the pathogen to colonize maize tissues. Exactly how HC-toxin evades maize defenses remains elusive, and unlocking this mystery using a combination of genetic, genomic and molecular approaches constitutes a major thrust of the Johal lab. Efforts include an investigation into the evolutionary origin of the Hm1 disease resistance gene. This gene evolved naturally in maize and it confers complete resistance to C. carbonum by inactivating HC-toxin. An allele of Hm1 confers adult plant resistance, as does the functional allele at the hm2 locus. Why and how these genes behave this way is also pursued. Dr. Johal’s second project concerns a class of mutations that are collectively known as disease lesion mimics (DLMs). These mutants are recognized by their ability to produce symptoms that mimic those that are normally produced during maize’s encounter with various pathogens. The Johal lab has contributed substantially in revealing the biological underpinnings some of these DLMs and is continuing to do so for more and more of these mutants. In addition, DLMs are being used as reporters to uncover natural variation capable of suppressing or enhancing their severity. The cloning and characterization of such natural variants are expected to provide valuable tools and targets for coping with a variety of stresses, both biotic and abiotic. The third project area concerns genes and mechanisms that impact the height and quality of the maize stalk. Again, the approach is to generate and/or identify natural mutants that compromise these stalk traits. The genes underlying these variants are then cloned either by transposon tagging or by map-based cloning approaches. Two recent accomplishments in this area include the cloning of the brittle stalk -2 (bk2) and brachytic-2 (br2) genes. While bk2 encodes a COBRA-like protein required to assemble secondary cell walls, br2 encodes a multidrug resistance protein involved in the polar movement of auxins from the top of the plant to the bottom. An ortholog of the br2 gene was shown to be defective in the sorghum dw3 mutant, which despite its instability has been used extensively in sorghum breeding programs. The molecular mechanism underlying dw3 instability and ways to correct it were also revealed.
|Sharon Kessler||Plant Biology|
The Kessler Lab studies the cell and molecular mechanisms that control pollination and seed yield in flowering plants.
|Damon Lisch||Plant Biology|
I am interested in the regulation and evolution of plant transposable elements. Transposable elements, or transposons, are, by far, the most dynamic part of the eukaryotic genome, and the majority, often the vast majority, of plant genomes are composed of these genomic parasites. Although they are an important source of genetic novelty, transposons can also be a significant source of detrimental mutations. Because of this, plants (and indeed all eukaryotes) have evolved a sophisticated “immune system” whose function is to detect and epigenetically silence them. My research centers on determining the means by which transposons are detected and then maintained in a silenced state. To do this, the my lab has focused on MuDR, a transposon in maize that can be reliably and heritably silenced by a naturally occurring derivative of that element. In addition to its role in transposon control, epigenetic silencing is employed by plants and animals for a wide variety of other purposes, and epigenetic silencing pathways in plants are particularly diversified. However, whatever else they do, all of these pathways appear to be involved in transposon silencing as well, making transposons an excellent model for understanding how epigenetic information is encoded and propagated. Finally, transposon mobilization and subsequent silencing can have dramatic effects on the expression of plant genes. Current work in the my lab combines a detailed analysis of MuDR transposon silencing with a global analysis of the effects of transposon silencing on plant gene function and phenotypic variation.
|Dr. Scott McAdam||Plant Evolutionary Physiology|
Evolution of drought tolerance and response in plants, from stomatal behavior to xylem physiology and hormones
|Gordon McNickle||Plant Ecology|
Dr. McNickle's research investigates the strategies used by plants to acquire resources, how interactions among competitors, enemies and mutualistic partners alter these strategies, and how all of these interactions shape species coexistence and community structure - with an emphasis on below ground interactions. Most ecological interactions take on all the essential features of a game, and most work in the lab relies on evolutionary game theory as a central tool to make predications about plant systems. Dr. McNickle relies on a mixture of mathematical modeling to develop explicit hypotheses and field or greenhouse experiments as appropriate to test these hypotheses.
|Tesfaye Mengiste||Molecular Genetics of Plant Immunity to Fungal Pathogens|
Research in Mengiste lab focuses on molecular-genetics of fungal resistance in model and crop plants.
|Christopher Oakley||Ecological and evolutionary genetics of plants|
The Oakley lab is broadly interested in the ecological and evolutionary genetics of plants. One main focus of our research is the genetic basis of local adaptation. Local genotypes are often found to grow, survive, and/or reproduce better than non-local genotypes, suggesting that adaptation to one environment is costly in other environments (fitness tradeoffs across environments). Despite much empirical study, little is known about the mechanisms and genetic basis of local adaptation. Using locally adapted populations of Arabidopsis thaliana from near the northern and southern edge of the native rage, we investigate the genetic basis of local adaptation, adaptive traits (e.g., freezing tolerance), and genetic tradeoffs (fitness tradeoffs attributable to individual loci). We have developed a variety of genetic stocks that we use in field and growth chamber experiments in concert with genetic and genomic approaches.
A second main focus of our research is the consequences of genetic drift for adaptation and population persistence. A number of factors common in natural populations (e.g., a history of population bottlenecks) can increase both the chance loss of beneficial mutations and the chance fixation of deleterious mutations. Heterosis, the increased fitness in crosses between populations relative to fitness within populations, is thought to be due in part to the masking of these fixed deleterious recessive alleles in the heterozygous state. We are investigating the geographic pattern and genetic basis of heterosis in natural populations of A. thaliana to study the balance between selection and genetic drift in nature.
|Robert Pruitt||Plant Molecular Biology|
Bacterial interactions with plants, with a particular focus on human pathogens that contaminate fresh produce and how that affects food safety. The goals of this research are to understand how pathogenic bacteria are introduced into the plant system and what bacterial, plant and environmental factors allow them to survive and proliferate.
|Christopher Staiger||Plant Cell Biology|
The Staiger lab uses state-of-the art imaging and quantitative cell biology approaches to investigate how a dynamic network of cytoskeletal filaments coordinates cell growth and response to phytopathogens.
|Dan Szymanski||Cell Biology|
The use of multivariate live cell imaging and finite element computational modeling to discover how plant cells dynamically reorganize the cytoskeleton and the cell wall during cell morphogenesis. Another major project in the lab is the development of a proteomics pipeline that can be used to broadly discover and analyze protein complexes in both model and crop species.
|Gyeongmee Yoon||Plant Biology|
Dr. Yoon’s research focuses on unraveling the molecular mechanisms that control plant hormone ethylene function and its role in plant stress responses.
Chunhua Zhang’s lab uses a combination of chemical genetics and live cell imaging approaches to understand the mechanisms of plant vesicle trafficking.
|Yun Zhou||Plant Cell and Developmental Biology|
We explore the cellular and molecular mechanisms in control of meristem development and stem cell homeostasis in Arabidopsis and in ferns, using both experimental and computational approaches.