Progress 10/01/10 to 09/30/13
Outputs
Target Audience: Plant scientists interested in the evolutionary processes that contribute to the diversity of land plants. Changes/Problems: Michael Zanis effectively left Purdue University in the summer of 2012 although he retained a partial appointment (approximately 20% FTE) until his contract ended in May 2013. As a result, there has been very limited progress on this project during the last year. What opportunities for training and professional development has the project provided? One PhD student and one MS students completed their degrees under Dr. Zanis's supervision while working on aspects of this project. How have the results been disseminated to communities of interest? Some of the results from this project have been presented at various scientific meetings. Research papers for publication in journals are in preparation. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
- Michael Zanis effectively left Purdue University in the summer of 2012 although he retained a partial appointment (approximately 20% FTE) until his contract ended in May 2013. As a result, there has been very limited progress on this project during the last year.
Publications
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: My research at Purdue focuses on the role of mutational events in diversifying aspects of satmen and carpel development. The stamen and carpel represent the reproductive structures responsible for the production of pollen and fruit. My most recent work has shown that specific genes regulating reproductive organ development have been duplicated independently in multiple flowering plant species - including those that are or agricultural importance. My research examines a set of MADS-box transcription factors that play a critical role in regulating male (stamens) and female (carpel) reproductive organ development. These genes underlying reproductive organ development are master genes ultimately regulating fruit and pollen production. These MADS-box transcription factors play an important role in regulating a complex network of down stream genes that initiate and control stamen and carpel development. We are now testing the role of these duplicate genes in diversifying genetic and developmental pathways in a broad range of plants. The plants we study include agriculturally important plants (maize, Sorghum, oats) and emerging or poorly studied crops such as Miscanthus, and Zizania (North American Wild Rice). PARTICIPANTS: Dr. Renate Wuresig TARGET AUDIENCES: Botanist, systematist, and horticulturalists. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
My students and I are using a combination of approaches to study the diversification of genes controlling stamen and carpel (fruit) production across flowering plants. These approaches include transgenic approaches using the model plant species Arabidopsis, comparisons of DNA sequences to identify significant mutations between duplicate genes and species and finally we use in situ hybridizations and RT-PCR to examine expression variation across species and duplicate genes. We have identified sets of MADS box genes from diverse flowering plant species that are able to ectopically convert petals into stamens and also a set genes that can cause sepals to develop carpel like features. These findings will provide greater detail into our understanding of the genetic regulation of stamen and fruit development. By identifying important mutations in these MADS box genes, our research also opens new possibilities into the manipulation of stamen and fruit genetic pathways for the increase of fruit production. My first Ph.D. student completed and successfully defended her dissertation this last summer, 2012. We are currently working on submitting her thesis chapters as manuscripts.
Publications
- No publications reported this period
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: My research at Purdue studies the evolution of female and male reproductive organ development and genetics in flowering plants, including agriculturally important grass species. The male (stamen) and female (carpel) organs of flowering plants responsible for the production of pollen and fruit, respectively. My lab's research has shown that genes regulating reproductive organ development have been duplicated independently in multiple flowering plant species, including those that are of agricultural importance. These genes are MADS-box transcription factors, named C class MADS-box genes, and regulate early and late stamen and carpel development. We have reconstructed the evolutionary history, through phylogenetic analysis, of C class MADS-box genes. We have also completed a survey of C class MADS-box gene expression patterns in distantly related flowering plants. Finally, we have examined the consequence of constitutively expressing duplicate C class MADS-box genes in the model plant species Arabidopsis thaliana. This research is the foundation of one of my Ph.D. students who successfully defended her thesis. PARTICIPANTS: Walker, Sheryl A., M.S. student (trained in Dr. Zanis' lab) Wuersig, Renate, Ph.D. student (trained in Dr. Zanis' lab) Zanis, Michael, J. Ph.D. - Principal Investigator TARGET AUDIENCES: Botanists and plant scientists. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The phylogeny of these C class MADS-box genes shows that gene duplication mutations (or even whole genome duplications) have played a significant role in the evolutionary diversification of these genes in flowering plants. Our survey of C class MADS-box gene expression in a broad sample of distantly related flowering plants shows that these C class MADS-box genes are expressed in male and female reproductive organs in all flowering plants. However, our expression work has also found that in some species these genes are expressed in non-reproductive organs such as leaves. The expression of C class MADS-box genes in leaves in some non-model plant species is a novel finding and has not been reported in the model plant species such as Arabidopsis or rice. The constitutive expression of C class MADS-box genes from different flowering plant species in the model plant Arabidopsis has a number of phenotypic effects. We have confirmed previous research showing petals can be homeotically converted into stamens. We have also found that the constitutive expression of C class MADS-box genes can also result in failure of ovules (which when mature are the seed) to develop. Our research and results indicate possible mechanisms by which stamen and carpel developmental programs may be modified to enhance pollen, fruit, or seed production.
Publications
- Wuersig, Renate; Zanis, Michael, J. 2010. The Natural History of C- and D-class MADS-box Genes: Insights from Phylogenetic Analyses. Botanical Society of America, Providence (Abstract: Meeting)
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: My research at Purdue focuses on the role of mutational events in diversifying aspects of stamen and carpel development. The stamen and carpel represent the reproductive structures responsible for the production of pollen and fruit. My most recent work has shown that specific genes regulating reproductive organ development have been duplicated independently in multiple flowering plant species - including those that are of agricultural importance. My research examines a set of MADS-box transcription factors, C class MADS-box genes, that play a critical role in regulating male (stamens) and female (carpel) reproductive organ development. These genes underlying reproductive organ development are master genes ultimately regulating fruit and pollen production. These MADS-box transcription factors play an important role in regulating a complex network of down stream genes that initiate and control stamen and carpel development. PARTICIPANTS: Sheryl A. Walker is a graduate student in my lab working on her Masters degree Rebecca C. Tucker is a graduate student in my lab working on her Masters degree Renate Wuersig is a graduate student in my lab working on her Ph.D. TARGET AUDIENCES: This research targets a a diverse audience including colleagues at the Botanical Society of America, graduate students, and undergraduate students. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We are now testing the role of these duplicate genes in diversifying genetic and developmental pathways in a broad range of plants. The plants we study include agriculturally important plants (maize, Sorghum, oats) and emerging or poorly studied crops such as Miscanthus, and Zizania (North American Wild Rice).
Publications
- No publications reported this period
- Wuersig, Renate; Zanis, Michael, J. 2010. The Natural History of C- and D-class MADS-box Genes: Insights from Phylogenetic Analyses. Botanical Society of America, Providence (Abstract: Meeting)
- Walker, Sheryl A.; Tucker, Rebecca C. ; Zanis, Michael, J. 2010. Patterns of Molecular Evolution Across Developmental Genes in Zizania Species (North American wild rice). Botanical Society of America, Providence (Abstract: Meeting)
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Progress 11/07/08 to 10/30/09
Outputs
OUTPUTS: My research at Purdue focuses on the role of mutational events in diversifying species and populations of plants. My most recent work has shown that specific genes regulating reproductive organ development have been duplicated independently in multiple flowering species. My current research examines a set of MADS-box transcription factors that play a critical role in regulating male (stamens) and female (carpel) reproductive organ development. These genes underlying reproductive organ development are master genes ultimately regulating fruit and pollen production. These MADS-box transcription factors play an important role in regulating a complex network of down stream genes that initiate and control stamen and carpel development. We are now testing the role of these duplicate genes in diversifying genetic and developmental pathways in a broad range of plants. The plants we study include agriculturally important plants (maize, sorghum, oats) and emerging or poorly studied crops such as Miscanthus, and Zizania (North American Wild Rice). PARTICIPANTS: I have worked with both graduate and undergraduate students. Renate Wursig is a graduate student in my lab who has played a pivotal role in the study of genes underlying reproductive organ development in plants. Her work is the basis of her dissertation. Sheryl Walker is an undergraduate researcher in my lab and has helped characterize genes underlying development (including reproductive organ development) in North American Wild Rice. She anticipates going to graduate school in Genetic Counseling. TARGET AUDIENCES: My audience is both basic and applied plant biology scientists. My work is routinely presented at meetings that have a mixture of basic and applied scientist from both academia, government, and industry. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
I and my students are using a combination of approaches to study the duplicate gene evolution. We use a comparative approach, sampling pre-duplication species, with one gene copy, and post-duplication, species that have have two gene copies. By comparing the gene sequences of pre and post-duplication species we are able to differentiate the types of mutations that underlie the long-term evolutionary maintenance of gene duplicates. We examine the functional role of these genes using gene expression and transgenic complementation experiments. My work has revealed that the genomes of grasses are composed of a mosaic of temporally spaced ancient and recent gene duplications. My work has also revealed that the genetic pathway controlling reproductive organ development has diversified via gene duplications in the agriculturally important grass family (Poaceae) as well as other major flowering plant lineages. Through sequence comparisons we have identified several independent gene duplications in C class genes - genes that control reproductive development in plants. Plants that have single C class gene are able to specify both stamen and carpel development with this single gene. Plants that have two C class genes appear to specify male and female reproductive organ development differentially; one C class gene specifies stamens and the other specifies carpels. We are now functionally characterizing the changes that specifically lead to this partition of gene function. Our sequence comparisons on non-coding DNA have revealed a site of conserved DNA sequences that may be responsible for regulating the differential gene expression of these C class genes. Our results have resulted in several interesting insights that will have applications to a broad range of crop plants in terms of understanding and improving fruit and seed production.
Publications
- Sindhu, A, Chintamanai, S, Brandt, AS, Zanis, MJ, Scofield, SR, Johal, GS. 2008. Guardian of Grasses: Specific Origin and Conservation of a Unique Disease Resistance Gene in the Grass Lineage. PNAS. 105: 1762-1767.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: My lab looks at the control of organs that ultimately produce pollen (stamens - male reproductive organ) and organs that produce seeds (carpels - female reproductive organs) by genes that have duplicated. These genes are called C class genes and represent transcription factors that regulate stamen and carpel development. Genes that have duplicated, such as C class genes, may have split their function into distinct roles. We have identified multiple independent duplications of C class genes across flowering plants. These independent duplicate C class genes duplicated from a single gene sequence. We are now investigating how these genes have changed function following a gene duplication event. We are also using comparative genomics and have identified regions of DNA, in these C class genes, that may regulate the expression of these duplicate genes.
TARGET AUDIENCES: Plant breeders and molecular biologists
Impacts
Through sequence comparisons we have identified several independent gene duplications in C class genes - genes that control reproductive development in plants. Plants that have single C class gene are able to specify both stamen and carpel development with this single gene. Plants that have two C class genes appear to specify male and female reproductive organ development differentially; one C class gene specifies stamens and the other specifies carpels. We are now examining what changes specifically lead to this partition of gene function. Our sequence comparisons on non-coding DNA have revealed a site of conserved DNA sequences that may be responsible for regulating the differential gene expression of these C class genes.
Publications
- Zanis, MJ. 2007. Grass spikelet genetics and duplicate gene comparisons. International Journal of Plant Sciences. 168:93-110.
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Progress 10/01/05 to 09/30/06
Outputs
I am investigating duplications in gene that are essential to stamen and carpel development in flowering plants. These genes are C class genes as defined by the ABC model of flower development. My primary focus is on the grasses, including maize and rice, however my lab is also exploring other flowering plant lineages that have had independent duplications of C class genes. I am examining both cis-regulatory changes (non-coding DNA) and coding changes in these duplicate C class genes. Many of the duplicate genes appear to have partitioned gene function. Thus those species that have a single C class gene regulate both stamen and carpel development with one gene. Species with two C class genes, one copy regulates stamen development and the other regulates carpel development. We are using mutant Arabidopsis, in which all C class genes have been knocked-out, as a heterologous system with which to over-express duplicate C class genes from a range of different species. With
this research we will be able to identify the key amino acid changes that have occurred following a gene duplication event that resulted in a partition of gene function. I have been at Purdue for one year, in this time I have had two graduate students join my lab. My lab and I have isolated single copy and duplicate C class genes from several diverse species of flowering plants with a emphasis on grasses. Many of these genes have been cloned into binary vectors and either have or will be transformed into Arabidopsis. We have also examined the patterns of gene expression of both single and duplicate C class genes using RT-PCR and in situ hybridizations.
Impacts
My research is likely to have large impact on: 1) our basic understanding of how genes change through gene duplication events and 2) how we may be able to use naturally occurring variation in duplicate genes regulating development to modify and improve crop yields. These modifications and improvements may most notably be detected or implemented in crops used for biofuel production. For example we may be able to enhance the number of kernels produced on an ear of corn using naturally occurring duplicate C class genes. Alternatively we will be able to target a specific gene to be expressed only in the ear of corn using cis-regulatory elements identified in our work on C class genes. My research on the diversification of genes regulating stamen (male) and carpel (female) development will provide fundamental insights into gene changes following a gene duplication event and will provide useful information for modification of plants used in the production of biofuels.
Publications
- No publications reported this period
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