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Iaffaldano Thesis Final_revised.pdf (7.52 MB)

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Evaluating the Development and Potential Ecological Impact of Genetically Engineered Taraxacum kok-saghyz.

Iaffaldano, Brian
http://rave.ohiolink.edu/etdc/view?acc_num=osu1452174223

Abstract Details

2016, Doctor of Philosophy, Ohio State University, Horticulture and Crop Science.
Natural rubber is a biopolymer with irreplaceable properties, necessary in tires, medical devices and many other applications. Nearly all natural rubber production is dependent on a single species, Hevea brasiliensis. Limitations of Hevea compel the investigation of additional rubber producing crops. One potential alternative is Taraxacum kok-saghyz (TK), which is a wild, widely adapted, and phenotypically diverse species of dandelion. TK domestication may include genetic engineering or breeding to introduce herbicide resistance and allocate more resources to rubber production. We have demonstrated stable transformation in Taraxacum species using Agrobacterium rhizogenes to introduce genes of interest. Inoculated roots regenerate into plantlets without any hormonal treatments or additional manipulations. Transformed plants were reproductively viable and genes of interest segregated independently. This method was then leveraged to conduct CRISPR/Cas9 genome editing. We have investigated the potential for gene flow from TK, into the ubiquitous weedy relative of TK, the Common Dandelion, T. officinale (TO), in greenhouse and outdoor experiments. In controlled crosses, TK pollinated by apomictic TO produced a small number of viable seed, 23% of which were the result of hybridization. In outdoor seed production areas heavily contaminated with TO, seed produced was screened for hybrids over a three year period using phenotypic screening followed by genetic verification. Hybridization between TK and TO was only observed in these areas during one of these years on the order of 0.001%, where bees were introduced to augment pollination. While we exclusively detected apomictic TO in North America, tools are needed to detect sexual reproduction by such populations, which may be absent or very rare. Accordingly, TK germplasm possessing scorable transgenic traits was created for this purpose. Traits such as kanamycin resistance, glufosinate resistance and the expression of florescent proteins and the transcription factor IbMYB, may be used to determine if rare pollen mediated hybridization events between TK and TO can occur. Collectively, this research provides a toolkit to develop genetically engineered TK and also understand the potential ecological impact of biotech TK. While the potential for hybridization exists, the ability of novel traits to fully introgress within TO may be limited, however, more work is needed to understand the potential longevity of hybrids in natural settings. New tools such as CRISPR/Cas9 offer the opportunity to accelerate the domestication of new crops, such as TK and may be used to further minimize ecological impact.
Katrina Cornish (Advisor)
165 p.
Bioinformatics; Ecology; Genetics; Plant Biology; Plant Sciences
Taraxacum kok-saghyz; Biotechnology; CRISPR; Rubber; Hairy root; Rhizogenes; Hybridization; Gene flow; Taraxacum brevicorniculatum; Molecular Markers;

Recommended Citations

Citations

  • Iaffaldano, B. (2016). Evaluating the Development and Potential Ecological Impact of Genetically Engineered Taraxacum kok-saghyz. [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452174223

    APA Style (7th edition)

  • Iaffaldano, Brian. Evaluating the Development and Potential Ecological Impact of Genetically Engineered Taraxacum kok-saghyz. 2016. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1452174223.

    MLA Style (8th edition)

  • Iaffaldano, Brian. "Evaluating the Development and Potential Ecological Impact of Genetically Engineered Taraxacum kok-saghyz." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452174223

    Chicago Manual of Style (17th edition)

osu1452174223
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This open access ETD is published by The Ohio State University and OhioLINK.