The 7th
Annual
NC
Undergraduate
Summer Research Symposium
Plant Pathology Kelman
Scholars abstracts
Abstracts are listed in
alphabetical order by the last name of the corresponding author.
|
Dave, Puja V. |
|
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Home Institution: |
Columbia
University |
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Program: |
Plant Pathology Kelman Scholars |
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College: |
CALS |
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Department(s): |
Plant
Pathology |
|
Research |
Noureddine
Hamamouch/Plant Pathology Eric
L. Davis/Plant Pathology |
|
Title of Presentation: |
Expression
Analysis of Arabidopsis Pathogenesis-Related Genes in Response to Nematode
Infection |
Sugar Beet Cyst nematode (Heterodera schachtii) and root-knot
nematode (Meloidogyne incognita) are
sedentary endoparasites of plant roots that are major pathogens of crop plants
(Davis et al., 2004). Nematodes of the infective juvenile second-stage
penetrate through plant roots and must induce elaborate transformations of
selected root vascular cells into complex, multinucleate feeding sites to
provide nutrition for the subsequent sedentary parasitic life stages, causing
serious yield reduction. Pathogenesis-Related (PR) proteins are a group
of proteins that are induced in response to pathogen attack and are widely used
as molecular markers for resistance response to pathogens and systemic acquired
resistance. However, little is known about their expression in response to
nematodes. In this study, a time course expression analysis of five Arabidopsis
PR genes (PR1 to PR5) in response to root-knot nematode and beet cyst nematode
is analyzed using Reverse Transcription Polymerase Chain Reaction (RT-PCR).
Total RNA was extracted from roots and shoots of Arabidopsis plants at 0, 5, 9,
and 14 days post nematode infection. Complementary DNA (cDNA) was synthesized
from equal amounts of RNA and used as a template for the amplification of
specific PR genes. The resulting PCR product was analyzed on 1% agarose gel.
This study will shed insight onto the temporal expression pattern of specific
PR genes during root-knot and beet cyst nematode infection and may be used in
engineering plant resistant to nematodes.
|
Kaur, Amarpreet |
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Home Institution: |
NCSU |
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Program: |
Plant Pathology Kelman Scholars |
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College: |
CALS |
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Department(s): |
Biochemistry |
|
Research |
Paola
Veronese/Plant Pathology |
|
Title of Presentation: |
Characterization
of Arabidopsis-Verticillium spp.
Interactions |
Plant pathology is the
science of diagnosing and managing plant diseases. Plant diseases affect the
existence, adequate growth, and productivity of all kinds of plants and thereby
affect one or more of the basic prerequisites for a healthy, safe life for
humans. It is estimated that in the United States, alone, despite the control
measures practiced, each year, crops worth $9.1 billion are lost to disease
(Agrios, 2005). Plant disease management relies mainly on chemical control and
use of resistant cultivars. Due to the negative effects on the environment
caused by pesticides and other chemicals, it is necessary to develop new
methods of prevention. However, first, a better general knowledge of the
plant-microbe interaction is required. Our research aims to uncover information
on plant resistance/tolerance mechanisms active against soil borne fungi of the
genus Verticillium. Verticillium spp.
causes vascular diseases called Verticillium wilts in a broad range of crop
plants in temperate areas all over the world. There are no curative measures
once a plant is infected. In our experiments, we are using the model plants Arabidopsis thaliana to study the
interaction with V. dahliae and V. longisporum Both Verticillium spp. induce in Arabidopsis stunted growth, anthocyanin
accumulation and early flowering disease symptoms however, only V. longisporum causes strong chlorosis. We are correlating
the observed differential expression of the disease symptom with the pathogen
colonization rate of the plant tissues and with the expression of selected
plant defense genes. Likely, our results will contribute to a better
understanding of the molecular genetics of plant responses to vascular pathogens.
|
Lee, Marissa R. |
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Home Institution: |
Swarthmore College |
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Program: |
Plant Pathology Kelman Scholars |
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College: |
CALS |
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Department(s): |
Plant Pathology |
|
Research |
Shuijin Hu/Plant Pathology |
|
Title of Presentation: |
Do Arbuscular Mycorrhizal
Fungi Enhance the Invasibility of Japanese Stiltgrass (Microstegium vimineum)? |
High levels of arbuscular mycorrhizal (AM) infection have
been observed in multiple, highly successful exotic plants in the field,
including Microstegium vimineum.
However, the impact of that symbiosis on the success of M. vimineum remains unclear. A preliminary experiment showed
that M. vimineum accumulated more
biomass in sterilized soil with AM-fungi inoculum than in pre-invaded field
soil, suggesting that AM-fungi may promote its growth. In this study, the
hypothesis that M. vimineum
experiences positive feedback in pre-invaded North American soil due in part to
mycorrhizal associations was tested by growing M. vimineum (1) in pre-invaded field soil and sterilized soil to
determine the plant-soil feedback, and (2) in sterilized soil with AM-fungal
inocula to determine the AM effect. While an N addition treatment was
designed to assess the effect of nutrient release resulting from soil
sterilization, the differences in native versus inoculum AM-fungal activity was
also evaluated by growing M. vimineum
in soils from the pre-invaded field site and with additional AM-fungi.
Results from this experiment will help us to better understand interactions
between exotic plants and native soil biota so as to develop effective
strategies for restoration.
|
Montefiori, Lindsey E. |
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Home Institution: |
NCSU |
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Program: |
Plant Pathology Kelman Scholars |
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College: |
CALS |
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Department(s): |
Microbiology |
|
Research |
Paola Veronese/Plant
Pathology Selvakumar Veluchamy/Plant
Pathology |
|
Title of Presentation: |
Identification of
Phytopathogenicity Determinants in the Soil Fungus Verticillium dahliae |
Verticillium
dahliae is the primary causal agent
of Verticillium wilt, a vascular disease that affects hundreds of crop plants
worldwide. V. dahliae is a
soil-borne pathogen that infects its host by penetrating the root system and
spreads systemically through the xylem. Because Verticillium wilts are
difficult to control, there are many concerted efforts across the world to
understand the molecular genetics of plant-V.
dahliae compatible (resulting in disease) and incompatible (resulting in
resistance) interactions. We aim to identify V. dahliae genes that play a major role in pathogenicity using
functional genomics. Our efforts are facilitated by the recent release by
the Broad Institute at MIT (http://www.broad.mit.edu)
of the genome sequence of the V. dahliae
lettuce isolate Ls17 (VdLs17). We used the sequence of 234 proteins of
the fungal pathogen Magnaporthe grisea
that are known to be involved in pathogenicity mechanisms to identify candidate
homologues in the V. dahliae
genome. M. grisea is the causal
agent of rice blast disease; its genome was the first plant pathogen genome to
be sequenced and, presently, this fungus is considered a model system because
of the large amount of information on its gene functions that has been already
generated. Our search for VdLs17 homologues was based on sequence
homology and performed using the BLASTp program. We identified 101 VdLs17
candidate homologues, 47 of which had corresponding expressed sequenced tags
(ESTs) that support the automated gene prediction. Our further
experiments focused on five of these genes for which we studied the expression
during in planta interaction using
quantitative real time (qRT)-PCR. The VdLs17 genes which are expressed
during colonization of susceptible lettuce plants will be targeted for gene
disruption by homologous recombination. The generated VdLs17 knock-out
mutants will be used in inoculation experiments to analyze the impact of gene
loss-of-function on induction of disease symptoms.
|
Muthigi, Ameeth |
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Home Institution: |
NCSU |
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Program: |
Plant Pathology Kelman Scholars |
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College: |
CALS |
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Department(s): |
Center for Biology of
Nematode Parasitism |
|
Research |
David M. Bird/Plant
Pathology Raja Kota/Plant Pathology |
|
Title of Presentation: |
A BAC-Based Physical Map
of the Soybean Cyst Nematode Genome (Heterodera
glycines) |
The soybean cyst nematode (SCN; Heterodera glycines) is a devastating obligate parasite of Soybean
causing one billion dollars in losses to the US economy per year and over ten billion
dollars in losses worldwide. While much is understood about the pathology of H. glycines, its genome is not well
characterized or fully sequenced. The main objective is to develop a BAC-based
physical map of the SCN genome which will help provide a powerful platform for
many areas of SCN genomics, including fine mapping and positional cloning of
important parasitism genes. The characterization of these genes would provide
us with a better understanding of molecular events and regulatory mechanisms involved
in plant parasitism by SCN and should allow the development of target specific
strategies to limit crop damage by these pathogens. To this effect, we have
constructed a BAC-based Fingerprinted Contig (FPC) physical map for the SCN
genome from 4224 BACs (avg insert size ~129 kb; 6 fold haploid genome coverage)
by using the four color High-Information-Content Fingerprinting (HICF) SNaPshot
assay. Five restriction enzymes (BamHI,
EcoRI, HaeIII, XbaI and XhoI)
were used to generate the fingerprints which were subsequently analyzed on the
ABI-3730XL. On average, we have observed approximately 80-100 restriction
fragments per lane. Data generated was processed using Genemapper and
Genoprofiler and contigs were assembled using the FPC software. Furthermore,
BAC-end sequencing of these clones in the Minimal tilling path (MTP) is being
performed to validate the contig assembly.
|
Norman, CaAdrian |
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Home Institution: |
University of South
Carolina |
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Program: |
Plant Pathology Kelman Scholars |
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College: |
CALS |
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Department(s): |
Plant Pathology |
|
Research |
Yeon Yee Oh/Plant
Pathology Ralph Dean/Plant Pathology |
|
Title of Presentation: |
Functional Characterization
of MGG_02647, Putative Secreted Protein in Magnaporthe Oryzae |
Magnaporthe
oryzae, commonly known as the rice
blast fungus, is a plant pathogen that causes a disease that affects rice and other
specific grains such as wheat or barley. The fungus is responsible for a
significant annual decrease in the production of rice, destroying enough rice
that could feed 60 million people each year. In order to understand the Magnaporthe oryzae fungus, it is
essential to know and understand the genes involved in the pathogenicity of the
fungus. The objective of this research is to find the genes responsible. One
gene thought to be involved in the pathogenicity is MGG_02647, which encodes a
putative secreted protein and is homologus to UV-1 in Bipolaris oryzae. To
characterize the biological function of MGG_02647, we constructed a gene
replacement cassette using adaptamer mediated PCR strategy, transformed it into
wild type Magnaporthe oryzae and
screened the knock out mutants. Also, for the study of over-expression and
localization of the protein, we generated the expression vector that contains
trpC or a native promoter, MGG_02647 and GFP (green fluorescent protein), and
introduced it into wild type strain as well.
|
Teisher,
Jordan K. Taylor, Troy A. |
|
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Home Institution: |
Moravian College |
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Program: |
Plant Pathology Kelman Scholars |
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College: |
CALS |
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Department(s): |
Plant Pathology |
|
Research |
Lane P. Tredway/Plant
Pathology |
|
Title of Presentation: |
A Phylogenetic Study of Sclerotinia homoeocarpa |
Sclerotinia homoeocarpa is the fungal pathogen that causes dollar spot, a major
disease of both warm- and cool-season turf grasses. Little is understood about
the fungus itself in terms of its diversity, phylogenetic relationships, and
proper taxonomic designation. The purpose of this study was to use a molecular
approach to explore the diversity and phylogeny of S. homoeocarpa. Fungal
specimens were isolated from turfgrass species collected in the United States
and the United Kingdom and grown on potato dextrose agar amended with
tetracycline, chloramphenicol, and streptomycin. Fifty-five isolates were
selected so that each population of fungi was represented. Isolates of Sclerotinia sclerotiorum, Rutstroemia
paludosa, and R. cuniculi were
also included for comparison. Four gene regions, ITS, b-tubulin, IGS, and
calmodulin, were amplified using PCR and then sequenced via cycle sequencing.
The resulting sequences were aligned using the ClustalW method, genetic
distances were calculated with the Kimura 2-parameter model, and a phylogenetic
tree was constructed using the neighbor-joining algorithm. The results obtained
to date indicate that genetic diversity among isolates is dependent on host
species rather than geographic location, with isolates from warm- and
cool-season turfgrasses separating into different clades. Within each clade, no
diversity has been detected regardless of the geographic location. Host species
is clearly a major factor that determines genetic diversity in populations of S. homoeocarpa causing dollar spot in
turfgrasses.
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Last modified June 2008 by Sharon E. Hunt