Plant Molecular Biology Consortium
The Plant Molecular Biology Consortium sponsors monthly seminars featuring nationally recognized academic and industrial plant scientists. Membership is open to plant scientists associated with any of North Carolina's colleges or universities and any representatives from companies involved in plant molecular biology.
31st Annual Plant Molecular Biology Retreat
September 8-10, 2017
Keynote Speaker: Joe Noel, Salk Institute
Full weekend schedule coming soon!
2016-2017 Seminar Series
Meetings are held from 6 to 8 p.m. at the North Carolina Biotechnology Center.
Meetings begin promptly at 6, light refreshments served at 7. No registration required to attend.
Download 2016-17 Seminar Series flier
|October 17, 2016||
Dr. Dani Zamir
Plant breeders advance food security by linking genes and genomes to traits affecting crop productivity. The availability of whole genome DNA markers made it possible to map quantitative trait loci (QTL) affecting complex traits such as yield and its stability and to deploy them in breeding, in our case, better tomatoes. Now we have the tools to move beyond ‘one gene at a time’ and address a higher level of organization: the role of interacting gene communities in determining the phenotype. Mapping of epistatic genes is difficult because typically the populations are small and the two-dimensional genome scans carry a heavy statistical penalty due to the multiple comparisons. Yet, epistasis is the bread and butter of daily breeding where successful hybrids maximize the benefits from the introduced trait into the right genetic context. To zoom-in on epistatic QTL, we developed backcross-inbred lines (BILs) between the drought tolerant wild tomato species Solanum pennellii and the cultivated tomato (Solanum lycopersicum). After two backcrosses the BILs, composed of 3000 lines, were selfed and these are being phenotyped for diversity of traits. The results clearly show that it is possible to identify interacting genomic regions that lead to epistatic morphological species-specific phenotypes as well as influencing total yield in the field.
|November 14, 2016||
Dr. Scott Michaels
"Large-Scale Heterochromatic Remodeling Facilitates DNA Repair"
Arabidopsis pericentromeric heterochromatin is condensed into structures called chromocenters that are enriched in histone H3 lysine 27 monomethylation (H3K27me1). Previously, we have shown that this mark is deposited by the homologous proteins ARABIDOPSIS TRITHORAX RELATED 5 (ATXR5) and ATXR6. We have used loss of function and gain of function mutants in these two proteins to investigate the role of H3K27 methylation in chromatin structure and gene regulation. atxr5,6 double mutants show a loss in H3K27me1 that results in the over replication of heterochromatin. This over replication results in DNA damage and extensive chromocenter remodeling into unique structures we have named Over Replication-Associated Centers (RACs). Super-resolution microscopy shows that RACs have a highly ordered structure, with an outer layer of condensed heterochromatin, an inner layer enriched in the histone variant H2Ax, and a low-density core containing foci of phosphorylated H2Ax (a marker of double-strand breaks) and the DNA-repair enzyme RAD51. These results suggest a novel mechanism for heterochromatic DNA-damage repair that involves large-scale chromatin remodeling. Using gain-of-function mutants in ATXR5/6, we are able to replace heterochromatic H3K27me1 with H3K27me2 or H3K27me3. In this way, we have been begun to investigate the functional significance of H3K27 methylation level on chromatin structure, DNA replication, and gene regulation.
|February 13, 2017||
Dr. Ralph Panstruga
“Mlo-Based Resistance: A Seemingly Universal “Weapon” to Combat Powdery Mildew Disease”
Loss-of-function mutant alleles of the barley Mlo locus are known to confer durable, broad-spectrum resistance against the powdery mildew disease caused by the ascomycete barley (Hordeum vulgare) pathogen Blumeria graminis f.sp. hordei. This type of antifungal immunity was discovered more than 70 years ago and has been widely used in European agriculture for more than 30 years. We recently showed that powdery mildew resistance conferred by mlo alleles is not restricted to barley, but also occurs in Arabidopsis, tomato and pea. The molecular basis of this unusual type of disease resistance remains, however, mysterious. We exploit the genetic and molecular tools available for the dicot reference species, Arabidopsis thaliana, and the monocot barley to get insights into the molecular mechanisms leading to mlo resistance. We further attempt to unravel the basic biochemical activity of Mlo proteins to understand their role in plant-powdery mildew interactions. In this context, we recently discovered that a myosin motor protein is required for mlo resistance in barley and that the Arabidopsis MLO2 protein seems to modulate prototypical plant responses upon exposure to microbe-associated molecular patterns (MAMPs). We also aim to transfer mlo-based resistance to species that are difficult to manipulate genetically, such as hexaploid bread wheat, by avoiding transgenic approaches.
|March 27, 2017||
Dr. Siobhan Brady
"Transcriptional Regulation of Plant Metabolism"
Regulation of plant development requires intricate communication with both primary and specialized metabolism in order to fuel growth. While transcriptional regulation of metabolism is evident from myriad whole genome-expression analyses, our understanding of which transcriptional regulators are responsible for these changes as well as their underlying mode of action is unclear. I will highlight our efforts on systematic mapping of transcriptional regulators of nitrogen metabolism, the tricarboxylic acid cycle and glucosinolate biosynthesis. Network analyses incorporating protein-DNA interaction data, gene expression and connectivity were used to identify critical regulators, most of which were shown to regulate growth and metabolism in planta. Finally, these analyses have shed light on modularity within these pathways and global perspectives on this additional mode of plant metabolic regulation.
|April 10, 2017||
Dr. Magdalena Bezanilla
"Actin and microtubule crosstalk impact cell patterning and development"
My research aims to determine how the cytoskeleton controls cell shape. As a model, my lab studies filamentous cells in the moss Physcomitrella patens in which ultimately the extracellular matrix – the cell wall – that encases each cell constrains cell shape. Yet, how the extracellular matrix is patterned over macroscopic length scales from within individual cells remains largely unknown in any eukaryote. Moss is uniquely suited to answer this question as it has a simple body plan and facile molecular genetics. Additionally, moss is multicellular and its cells differentiate into distinct tissues, providing a multicellular and developmental context to study cell morphogenesis. Using reverse genetics, high-end cellular imaging and biochemistry, my research is working to uncover the molecular mechanisms that regulate the cytoskeleton and interface with membrane trafficking to effect polarized growth and cell division.
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