<p> Environmental stresses involving flooding and the accompanying cellular low oxygen (hypoxia) constitute a major limitation to agricultural production worldwide. These stresses hinder the plant's ability to maintain energy production and growth. Yet, previous studies have shown that certain genes of group VII ethylene responsive factor (ERF) family of transcription factors play a functional role in the survival of submergence and low oxygen stresses in <i>Oryza sativa</i>(rice) and <i>Arabidopsis thaliana</i>. This study utilized a transient gene transfection assay of protoplasts to characterize gene networks regulated by the group VII ERFs by measuring the transcriptional activation of various promoters. Experiments revealed that orthologous genes are regulated by the group VII ERFs of both species. In rice, an ERF-type transcription factor, <i>SUB1A</i>, confers submergence tolerance by regulating carbohydrate metabolism, elongation growth, and hormonal responses. <i> SUB1A</i> is linked to the related genes <i>SUB1B</i> and <i> SUB1C</i>. Here, two alleles of <i>SUB1A</i> (<i>SUB1A-1 </i>, <i>SUB1A-2</i>) as well as one allele each of the other two genes (<i>SUB1B-1</i> and <i>SUB1C-1</i>) were shown to be transcriptional activators, and the nuclear localization of <i> SUB1A-1</i> and <i>SUB1C-1</i> was demonstrated. In <i> Arabidopsis</i>, core hypoxia responsive genes are governed by the N-end rule pathway of targeted proteolysis, in which proteins of the group VII ERFs (i.e., RAP2.12 and HRE2) are regulated post-translationally under hypoxic conditions. Transactivation experiments demonstrated that the trihelix protein HRA1 negatively regulates the transcriptional activation ability of RAP2.12 in the core hypoxia response. By contrast, HRE2 was not targeted by HRA1 downregulation, but was instead upregulated by RAP2.12 during the stress. Experiments involving truncations of HRA1 reveal that the coil-coil domain is functionally important for HRA1 interaction with group VII ERF complexes. These results with a rapid protoplast assay provide a foundation for future investigations into the low oxygen response gene network regulated by group VII ERF transcription factors binding to cis-regulatory elements, and modulated by the trihelix protein HRA1.</p>

<p> The objective of this study was to determine the effects of propagation media containing composted material on the rooting of hardwood and softwood blueberry cuttings. The physical properties were measured at the end of the experiment. The media used were pine bark fines, composted pine bark with ammoniated nitrogen added, hardwood bark and composted chicken manure, pine bark and cotton gin waste, and control (peat moss and perlite, 1:1). All treatments resulted in a low number of rooted hardwood cuttings compared to the control. The total number of roots per cutting and alive cuttings hardwood cuttings was increased by pine bark and ammoniated nitrogen compared to the remaining treatments. The control treatment resulted in the highest number of roots per softwood cutting. None of the treatments increased the number of roots of softwood cuttings and the number of alive cuttings was increased by all treatments compared to the control.</p><p></p>

<p> Nitrogen (N) fertility and irrigation costs are the greatest input expenses required for rice production in Mississippi, therefore N management and irrigation should be conducted in efficiently. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS, and the LSU AgCenter in Crowley, LA, to evaluate water and nitrogen management practices. Nitrogen use efficiency and yield were not different for alternate wetting and drying (AWD) systems compared to a traditional continuous flood. Additionally, experiments were conducted to test for differences comparing two experimental designs, randomized complete block (RCB) and split-plot (SP), for N-rate response trials in Mississippi. Rice grain yield response to N-rate was similar for RCB and SP designs, therefore either experimental design would be appropriate for N-response experiments in rice. Increasing efficiency of water and N management practices further improves environmental and economic benefits from rice production in Mississippi.</p>

<p> The Tennessee purple coneflower, <i>Echinacea tennesseensis</i> (Beadle) Small [Asteraceae], is a state (Tennessee) and formerly federal endangered species naturally found in cedar glades in middle Tennessee. A loss of habitat and a naturally restrictive geographic range contributed to this coneflower being listed as endangered. <i>E. tennesseensis</i> has recently been delisted from the federal Endangered Species List due to meeting the criteria of its recovery plan. These criteria included conservation efforts and the establishment of new populations of <i>E. tennesseensis.</i> Although the species had met the criteria for delistment, it was unknown how the reproductive fitness of the introduced colonies compared with that of the natural colonies. </p><p> Statistical analysis of germination rates found a marginally significant interaction between introduced and natural populations, especially at the Couchville site. Statistical analysis of seed set levels found significant differences in seed production between natural and introduced populations at the Vine and Vesta sites, with introduced populations having higher seed production than the natural populations at those sites. Introduced populations at the Vine site also had higher viable seed set. However, there were no differences at the Couchville site between the natural and introduced populations. In these analyses of seed traits that relate to fitness success, introduced colonies are just as, if not more, successful than natural colonies of <i>E. tennesseensis. </i> Seed production and viable seed set are similar or greater in introduced than natural colonies. Thus, introduced colonies appear to have the same regeneration potential as natural colonies and are just as reproductively functional, a key component when evaluating restoration success.</p>

<p> Growing crops for biofuel production on agricultural land has caused a debate between whether we should grow corn grain on productive, agricultural lands to feed a growing human population or to fuel our vehicles. This has increased interest in growing cellulosic biofuel feedstocks on marginal lands. Switchgrass (<i>Panicum virgatum</i> L.), a warm-season perennial grass, has been shown to be a viable bioenergy crop because it produces high yields on marginal lands under low water and nutrient conditions. West Virginia contains immense acreages of reclaimed surface mine lands and could offer enough area for the production of switchgrass as a feedstock for a biofuel industry.</p><p> The first study was established in 2008 to determine switchgrass yields of three different cultivars on two mine sites in West Virginia. The first site, which was reclaimed in the early 1990s using top soil and treated municipal sludge, consistently had the highest yield of the two sites with a sixth-year yield of 8.4 Mg Dry Matter (DM) ha^-1 averaged across varieties. Cave-in-Rock variety produced 13.0 Mg ha^-1 of biomass which was more than the other two varieties. The other site, Hobet, was prepared using crushed, unweathered sandstone in 2008 and average yields were 1.0 Mg ha^-1 for the sixth year of production.</p><p> The second study was conducted on two sites which were reclaimed with a layer of topsoil over gray overburden and seeded with Cave-in-Rock 2011. Fertilizer was applied at rates of 0, 33.6, and 67 kg N ha^-1. No fertilizer treatment yielded 0.32 Mg ha^-1 while the fertilizer treatments produced significantly higher yields.</p><p> The objective of the third study was to determine if cultivars and samples from fertilizer treatments differed in composition and theoretical ethanol yield. Compositional analysis was done using near infrared reflectance spectroscopy. It was determined that cultivars did not differ in theoretical ethanol yield with averages ranging from 364 to 438 L Mg^-1. Theoretical ethanol production from Cave-in-Rock was significantly higher ranging from 6,092 to 7,348 L ha^-1 due to its high biomass production. Fertilizer treatments did not greatly effect composition of switchgrass, but since it did improve yield this was reflected in greater ethanol production for fertilized treatments. Based on the information presented here, high biomass should be the goal for switchgrass grown for biofuel production. With proper soil substrate and fertilizer regime, switchgrass grown on reclaimed surface mines may have high enough yield and quality to support ethanol production in the future. </p>

Thesis (Ph.D.)--North Dakota State University, 2006. / (UnM)AAI3213959. Adviser: W. A. Berzonsky. Source: Dissertation Abstracts International, Volume: 67-04, Section: B, page: 1753.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3289. Adviser: Lila Vodkin. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3571. Adviser: A. Lane Rayburn. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

To promote recovery and crop potential of Hydrastis canadensis---a botanical threatened in Canada---wild populations were phytochemically surveyed. Berberine, hydrastine and canadine were characterized in root-rhizome, stem-leaf, and berry pulp. Comparisons with cultivated material showed no difference in alkaloid content, thus the medicinal value of cultivated material is not likely increased with addition of wild plants. Quantitative analyses suggested genetic diversity among wild populations. Regression analyses indicated a minor relationship between latitude and alkaloid yield. Because H. canadensis and other botanicals may cause adverse botanical-drug interactions, 22 botanicals were assayed for cytochrome P450 (CYP) 2C19, CYP3A4 and CYP19 inhibition. Eight botanicals inhibited CYP2C19 by &ge; 57%, 17 inhibited CYP3A4 by &ge; 40% and CYP19 by &ge; 50%, of which Arctostaphylos uva-ursi, H canadensis, Oenothera biennis, Rhodiola rosea and Sanguinaria canadensis were most potent. Regression analyses indicated berberine concentration was a significant factor in CYP3A4 and CYP19 inhibition.

We have investigated the use of the soybean seed coat as a bioreactor for the production of valuable proteins. In this system heterologous proteins are targeted to the hourglass cells. While seed coats currently have little commercial value, the introduction of high valued bio-products may generate new markets for Canadian industries and contribute towards the growth of rural economies. The seed coat system is based upon a promoter responsible for the production of soybean peroxidase (SBP) in the hourglass cell layer of the seed coat. SBP protein is thought to be synthesized as a pre-protein containing N- and C-terminal propeptides responsible for the intracellular localization of the mature SBP to the vacuole. We used this promoter and these signals to direct the synthesis and targeting of horseradish peroxidase (HRPC) from Armoracia rusticana and two laccases (LCC1 and LCC4) from the fungus Trametes versicolor. The cDNA sequences were codon-optimized for soybean, and fused with the SBP N- and C-terminal propeptides. A HIS tag was added to the C-terminal end of the mature protein to facilitate purification. Expression of the chimeric genes was driven by the Ep 1.5 kb fragment cloned from soybean peroxidase promoter. Fourteen lines of HRPC transgenics, 16 lines of LCC1 transgenics and 40 lines of LCC4 transgenics were generated by particle bombardment. The T 1 and T2 seeds of the transgenics were screened for peroxidase and laccase activity with the highest expressing lines further analysed by PCR and Western blots. The peroxidase activities measured in HRPC transgenics ranged from 0.02 to 3.09 U/mg protein while the laccase activities measured in laccase transgenics varied from 0 to 0.099 U/mg protein. In general these values are low compared to activities measured in the native species or in other transgenics. We have found that expression of HRPC and laccase as a trait is inheritable from T0 to T2 generation. The anti-LCC4, anti-HRPC antibodies were used to detect the expression of LCC4 and HRPC by Western blotting. A 35.4 kDa protein reactive with anti-HRPC and anti-HIS tag antibodies was found in the seed coat of an HRPC transgenic while a 77.6 kDa protein reactive with anti-LCC4 and anti-HIS tag antibodies was found in the seed coat of an LCC4 transgenic. These results support the use of the soybean seed coat as a bioreactor for the production of foreign proteins. The factors which affect foreign protein expression are fully discussed and future directions have been proposed to optimize the system.