Discipline: Ecology Environmental and Earth Sciences
Subcategory: Plant Research
Staffon Floyd Nicholas - Delaware State University
Co-Author(s): Co-Authors: Joey Cainong1, Antonette Todd1, Venu Kalavacharla1,2; 1Delaware State University, Dover, DE 19901, 2Center for Integrated Biological & Environmental Research (CIBER), Delaware State University, Dover, DE 19901
Switchgrass (Panicum virgatum) is a warm-season perennial grass native to North American marginal soils and is a promising source of cellulosic ethanol production. Most switchgrass cultivars are susceptible to anthracnose disease caused by the fungi Colletotrichum navitas, which reduces crop yield. The objective of this study is to identify gene expression associated with anthracnose resistance in switchgrass cultivar “Alamo”. Switchgrass plants grew for eight weeks before the inoculation with two isolates of C. navitas. Simultaneously, control plants were also grown under similar conditions, and inoculated with distilled water only. After 10 days, we collected the leaves from the inoculated plants that showed disease symptoms. The pathogen was re-isolated into a PDA plate and incubated at 24°C with 65% RH to complete the Koch’s postulates. DNA and RNA were isolated from the inoculated and control plants for molecular analyses. To verify primer integrity, we used polymerase chain reactions (PCR) with genomic DNA from the control plants. To check for differential expression of the selected disease resistance genes, the extracted RNA was synthesized to cDNA, which was then used in reverse transcriptase PCR. The PCR primers were previously derived from a differential expression study of anthracnose resistance genes between cultivars “Carthage” and “BN-309-69” that were naturally infected in the field. Preliminary results demonstrated no expression of the selected disease resistance genes. Currently, alternate genes are being sought to observe gene expression that are associated with “Alamo”. Analysis of differential expression of anthracnose resistance genes in switchgrass may help us to identify cultivars that may prove to be sufficiently resistant against the virulent C. navitas pathogen. References: Crouch, Jo Anne, et al. “Anthracnose disease of switchgrass caused by the novel fungal species Colletotrichum navitas.” Mycological research 113.12 (2009): 1411-1421. Ayyappan, Vasudevan, et al. “Comparative transcriptome profiling of upland (VS16) and lowland (AP13) ecotypes of switchgrass.” Plant cell reports 36.1 (2017): 129-150. Funders Acknowledgement: This research was funded by the National Science Foundation and the State of Delaware EPSCoR Grant No. IIA-1301765. We also want to thank Drs. Gary Bergstrom and Shawn Kenaley from Cornell University for the anthracnose isolates. Also thanks to the members of the Molecular Genetics and Epigenomics, and Plant Pathology laboratories at Delaware State University for their continuous support.
StaffonNicholas 2018 ERN Abstract.docxFunder Acknowledgement(s): This research was funded by the National Science Foundation and the State of Delaware EPSCoR Grant No. IIA-1301765.
Faculty Advisor: Venu Kalavacharla, vkalavacharla@desu.edu
Role: Prior to the start of the research, I reviewed relevant literature of the switchgrass plant and understood the necessary background of the pathogen that is used in this study. Working with the guidance of my mentors, I was involved in the design of the experiment, the inoculation with plant pathogens, extraction of DNA and RNA, polymerase chain reactions, gel electrophoresis and the analysis of the data. I also designed the poster with the guidance of my mentors.