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  Access Rights: Use restricted to UNT Community
  Partner: UNT Libraries
 Degree Discipline: Biochemistry
 Degree Level: Master's
 Collection: UNT Theses and Dissertations
Evidence for Multiple Functions of a Medicago Truncatula Transporter

Evidence for Multiple Functions of a Medicago Truncatula Transporter

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Date: December 2014
Creator: Huang, Ying-Sheng
Description: Legumes play an important role in agriculture as major food sources for humans and as feed for animals. Bioavailable nitrogen is a limiting nutrient for crop growth. Legumes are important because they can form a symbiotic relationship with soil bacteria called rhizobia that results in nitrogen-fixing root nodules. In this symbiosis, rhizobia provide nitrogen to the legumes and the legumes provide carbon sources to the rhizobia. The Medicago truncatula NPF1.7/NIP/LATD gene is essential for root nodule development and also for proper development of root architecture. Work in our lab on the MtNPF1.7/MtNIP/LATD gene has established that it encodes a nitrate transporter and strongly suggests it has another function. Mtnip-1/latd mutants have pleiotropic defects, which are only partially explained by defects in nitrate transport. MtNPF1.7/NIP/LATD is a member of the large and diverse NPF/NRT1(PTR) transporter family. NPF/NRT1(PTR) members have been shown to transport other compounds in addition to nitrate: nitrite, amino acids, di- and tri-peptides, dicarboxylates, auxin, abscisic acid and glucosinolates. In Arabidopsis thaliana, the AtNPF6.3/NRT1.1( CHL1) transporter was shown to transport auxin as well as nitrate. Atchl1 mutants have defects in root architecture, which may be explained by defects in auxin transport and/or nitrate sensing. Considering the pleiotropic phenotypes observed ...
Contributing Partner: UNT Libraries
Genetic Modification of Fatty Acid Profiles in Cotton

Genetic Modification of Fatty Acid Profiles in Cotton

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Date: August 2005
Creator: Rommel, Amy A.
Description: The industrial uses of cottonseed oil are limited by its fatty acid composition. Genetic modification of cotton lipid profiles using seed-specific promoters could allow cotton growers to produce valuable new oils in the seed without adverse effects on fiber quality and yield, therefore making this crop more commercially profitable. Transgenic cotton callus harboring a diverged fatty acid desaturase gene (FADX) from Momordica charantia was characterized for production of alpha-eleostearic acid (conjugated double bonds: 18:3 D9 cis, 11 trans, 13 trans), not normally found in cotton. Gas chromatography (GC) in conjunction with mass spectrometry (MS) confirmed production of alpha-eleostearic acid in the transgenic cotton tissues. A second series of transformation experiments introduced the cotton fatty acid thioesterase B (FATB) cDNA, fused to the seed-specific oleosin promoter into cotton to promote the over-expression of FATB, to generate cotton with increased palmitate in the cottonseed. PCR amplification, as well as fatty acid analysis by gas chromatography, confirmed introduction of the FATB cDNA in transgenic tissues. Collectively, these results demonstrate the feasibility of manipulating the fatty acid composition in cotton via transgenic approaches and form the basis for continued efforts to create novel oils in cottonseed.
Contributing Partner: UNT Libraries
Molecular and biochemical characterization of phospholipase D in cotton (Gossypium hirsutum L) seedlings.

Molecular and biochemical characterization of phospholipase D in cotton (Gossypium hirsutum L) seedlings.

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Date: May 2005
Creator: McHugh, John
Description: N-Acylethanolamines (NAEs) are enriched in seed-derived tissues and are believed to be formed from the membrane phospholipid, N-acylphosphatidylethanolamine (NAPE) via the action of phospholipase D (PLD). In an effort to identify a functional NAPE-PLD in cotton seeds and seedlings, we have screened a cotton seedling cDNA (cotyledon mRNA from 48 h dark grown seedlings) library with a 1.2 kb tobacco partial cDNA fragment encoding the middle third of a putative PLDβ/γ (genbank accession, AF195614) isoform. Six plaques were isolated from the Uni-ZAP lambda library, excised as pBluescript SK(-) phagemids and subjected to nucleotide sequence analysis. Alignment of derived sequences with Arabidopsis PLD family members indicated that the cDNAs represent six different PLD gene products -three putative PLD β isoforms and three putative PLD δ isoforms. The PLD β isoforms, designated Ghpldβ1a, GHpldβ1b and a truncated Ghpldβ1b isoform. Both the full-length PLD β proteins contained characteristic HKxxxxD catalytic domains, a PC-binding domain, a PIP2-binding domain and a C2 domain. In addition both cotton PLD β isoforms had a N-terminal "SPQY" rich domain which appeared to be unique to these PLDs. The three PLD δ isoforms, designated Ghpldδ1a, Ghpldδ1b and Ghpldδ1b-2 encode full-length PLDδ proteins, and like the above PLDs, contained the ...
Contributing Partner: UNT Libraries