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dc.contributor.authorKim, Changsoo
dc.date.accessioned2014-03-04T02:51:02Z
dc.date.available2014-03-04T02:51:02Z
dc.date.issued2007-12
dc.identifier.otherkim_changsoo_200712_phd
dc.identifier.urihttp://purl.galileo.usg.edu/uga_etd/kim_changsoo_200712_phd
dc.identifier.urihttp://hdl.handle.net/10724/24423
dc.description.abstractBermudagrass (Cynodon dactylon) is a major turfgrass species for sports fields, lawns, parks, golf courses, and general utility turfs in tropical and subtropical regions. Despite its ecological importance, much of its study has been dependent upon classical approaches. Information about Bermudagrass at the molecular level has been deficient although molecular information for other plants has been accumulated for the last two dacades. In the current study, we constructed a normalized cDNA library from leaf tissue of Bermudagrass in order to expand our knowledge of its transcriptome. We sequenced and annotated 15,588 expressed sequence tags (ESTs), which were deposited in the National Center for Biotechnology Information (NCBI) to be shared with other scientists. We also conducted cDNA array hybridization (macroarray) to profile genes responding to drought stress. A total of 120 and 69 genes were identified as up- and down-regulated, respectively. BLASTX annotation suggested that up-regulated genes may be involved in osmotic adjustment, signal transduction pathways, protein repair systems, and removal of toxins, while down-regulated genes were mostly related to basic plant metabolism such as photosynthesis and glycolysis. Using the cDNA sequences, we performed a comparative genomic study to gain new insight into the evolution of Bermudagrass. Results suggested that the common ancestor of the grass family experienced a whole genome duplication event at ca. 50.0 ~ 65.4 million years ago (MYA), before the divergence of the PACC and BEP clades at ca. 42.3 ~ 50.0 MYA. This evolutionary study also provided concrete evidence that the Chloridoideae and Panicoideae subfamilies diverged from a common ancestor at ca. 34.6 ~ 38.5 MYA. However, we were not able to find any evidence of a recent whole genome duplication event in Bermudagrass, possibly due to its autopolyploid genome structure.
dc.languageeng
dc.publisheruga
dc.rightspublic
dc.subjectBermudagrass
dc.subjectCynodon dactylon
dc.subjectcDNA library
dc.subjectExpressed sequence tag
dc.subjectEST
dc.subjectDrought stress
dc.subjectMacroarray
dc.subjectGene duplication
dc.subjectGenome evolution
dc.subjectGrass family
dc.subjectPoaceae
dc.subjectSynonymous substitution rate
dc.subjectPhylogenetic analysis
dc.titleDiscovery, expression profiling, and evolutionary analysis of Cynodon expressed sequence tags
dc.typeDissertation
dc.description.degreePhD
dc.description.departmentCrop and Soil Sciences
dc.description.majorAgronomy
dc.description.advisorAndrew Paterson
dc.description.committeeAndrew Paterson
dc.description.committeePaul Raymer
dc.description.committeeRussell Malmberg
dc.description.committeeRobert Carrow
dc.description.committeeWayne Hanna


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