Plant Biology Commons^™

Fungal Morphogenesis, Xiaorong Lin, J. Andrew Alspaugh, Haoping Liu, Steven D. Harris

Center for Plant Science Innovation: Faculty Publications

Morphogenesis in fungi is often induced by extracellular factors and executed by fungal genetic factors. Cell surface changes and alterations of the microenvironment often accompany morphogenetic changes in fungi. In this review, we will first discuss the general traits of yeast and hyphal morphotypes and how morphogenesis affects development and adaptation by fungi to their native niches, including host niches. Then we will focus on the molecular machinery responsible for the two most fundamental growth forms, yeast and hyphae. Last, we will describe how fungi incorporate exogenous environmental and host signals together with genetic factors to determine their morphotype and …

Gene Silencing In Microalgae: Mechanisms And Biological Roles, Eun-Jeong Kim, Xinrong Ma, Heriberto Cerutti

Center for Plant Science Innovation: Faculty Publications

Microalgae exhibit enormous diversity and can potentially contribute to the production of biofuels and high value compounds. However, for most species, our knowledge of their physiology, metabolism, and gene regulation is fairly limited. In eukaryotes, gene silencing mechanisms play important roles in both the reversible repression of genes that are required only in certain contexts and the suppression of genome invaders such at transposons. The recent sequencing of several algal genomes is providing insights into the complexity of these mechanisms in microalgae. Collectively, glaucophyte, red, and green microalgae contain the machineries involved in repressive histone H3 lysine methylation, DNA cytosine …

Sirna-Directed Dna Methylation In Plants, Meng Xie, Bin Yu

Center for Plant Science Innovation: Faculty Publications

DNA cytosine methylationis an important epigenetic process that is correlated with transgene silencing, transposon suppression, and gene imprinting. In plants, small interfering RNAs (siRNAs) can trigger DNA methylation at loci containing their homolog sequences through a process called RNAdirected DNA methylation (RdDM). In canonical RdDM, 24 nucleotide (nt) siRNAs (ra-siRNAs) will be loaded into their effector protein called ARGONAUTE 4 (AGO4) and subsequently targeted to RdDM loci through base-pairing with the non-coding transcripts produced by DNA-directed RNA Polymerase V. Then, the AGO4-ra-siRNA will recruit the DNA methyltransferase to catalyze de novo DNA methylation. Recent studies also identified non-canonical RdDM pathways …

The Role Of Ethylene In Plant Responses To K+ Deficiency, Daniel P. Schachtman

Center for Plant Science Innovation: Faculty Publications

Potassium is an essential macronutrient that is involved in regulating turgor , in driving plant growth, and in modulating enzyme activation. The changes in root morphology, root function, as well as cellular and molecular responses to low potassium conditions have been studied in the model plant Arabidopsis and in other plant species. In Arabidopsis ethylene plays a key role in roots in the transduction of the low potassium signal, which results in altered root function and growth. The first clues regarding the role of ethylene were detected through transcriptional profiling experiments showing changes in the expression of genes related to …

Redirection Of Metabolic Flux For High Levels Of Omega-7 Monounsaturated Fatty Acid Accumulation In Camelina Seeds, Huu Tam Nguyen, Hyunwoo Park, Karen L. Koster, Rebecca E. Cahoon, Hanh Nguyen, John Shanklin, Thomas E. Clemente, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Seed oils enriched in omega-7 monounsaturated fatty acids, including palmitoleic acid (16:1Δ9) and cis-vaccenic acid (18:1Δ11), have nutraceutical and industrial value for polyethylene production and biofuels. Existing oilseed crops accumulate only small amounts (<2%) of these novel fatty acids in their seed oils. We demonstrate a strategy for enhanced production of omega-7 monounsaturated fatty acids in camelina (Camelina sativa) and soybean (Glycine max) that is dependent on redirection of metabolic flux from the typical Δ9 desaturation of stearoyl (18:0)-acyl carrier protein (ACP) to Δ9 desaturation of palmitoyl (16:0)-acyl carrier protein (ACP) and coenzyme A (CoA). This was achieved by seed-specific co-expression of a mutant Δ9-acyl-ACP and an acyl-CoA desaturase with high specificity for 16:0-ACP and CoA substrates, respectively. This strategy was most effective in camelina where seed oils with ~17% omega-7 monounsaturated fatty acids were obtained.

Further increases in omega-7 fatty acid accumulation to 60–65% of the total fatty acids in camelina seeds were achieved by inclusion of seed-specific suppression of 3-keto-acyl-ACP synthase II and the FatB 16:0-ACP thioesterase genes to increase substrate pool sizes of 16:0-ACP for the Δ9-acyl-ACP desaturase and by blocking C18 fatty acid elongation. Seeds from these lines also had total saturated fatty acids reduced to ~5% of …

Production Of High Levels Of Poly-3-Hydroxybutyrate In Plastids Of Camelina Sativa Seeds, Meghna R. Malik, Wenyu Tang, Nii Patterson, Jihong Tang, Rachel L. Wellinghoff, Mary L. Preuss, Claire Burkitt, Nirmala Sharma, Yuanyuan Ji, Joseph M. Jez, Oliver P. Peoples, Jan G. Jaworski, Edgar B. Cahoon, Kristi D. Snell

Center for Plant Science Innovation: Faculty Publications

Poly-3-hydroxybutyrate (PHB) production in plastids of Camelina sativa seeds was investigated by comparing levels of polymer produced upon transformation of plants with five different binary vectors containing combinations of five seed-specific promoters for expression of transgenes. Genes encoding PHB biosynthetic enzymes were modified at the N-terminus to encode a plastid targeting signal. PHB levels of up to 15% of the mature seed weight were measured in single sacrificed T1 seeds with a genetic construct containing the oleosin and glycinin promoters.

A more detailed analysis of the PHB production potential of two of the best performing binary vectors in a Camelina …

Variable Frequency Of Plastid Rna Editing Among Ferns And Repeated Loss Of Uridine-To-Cytidine Editing From Vascular Plants, Wenhu Guo, Felix Grewe, Jeffrey P. Mower

Center for Plant Science Innovation: Faculty Publications

The distinct distribution and abundance of C-to-U and U-to-C RNA editing among land plants suggest that these two processes originated and evolve independently, but the paucity of information from several key lineages limits our understanding of their evolution. To examine the evolutionary diversity of RNA editing among ferns, we sequenced the plastid transcriptomes from two early diverging species, Ophioglossum californicum and Psilotum nudum. Using a relaxed automated approach to minimize false negatives combined with manual inspection to eliminate false positives, we identified 297 C-to-U and three U-to-C edit sites in the O. californicum plastid transcriptome but only 27 C-to-U …

Toward Production Of Jet Fuel Functionality In Oilseeds: Identification Of Fatb Acyl-Acyl Carrier Protein Thioesterases And Evaluation Of Combinatorial Expression Strategies In Camelina Seeds, Hae Jin Kim, Jillian E. Silva, Hieu Sy Vu, Keithanne Mockaitis, Jeong-Won Nam, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Seeds of members of the genus Cuphea accumulate medium-chain fatty acids (MCFAs; 8:0–14:0). MCFA- and palmitic acid- (16:0) rich vegetable oils have received attention for jet fuel production, given their similarity in chain length to Jet A fuel hydrocarbons. Studies were conducted to test genes, including those from Cuphea, for their ability to confer jet fuel-type fatty acid accumulation in seed oil of the emerging biofuel crop Camelina sativa. Transcriptomes from Cuphea viscosissima and Cuphea pulcherrima developing seeds that accumulate >90% of C8 and C10 fatty acids revealed three FatB cDNAs (CpuFatB3, CvFatB1, and CpuFatB4) …

Microrna Biogenesis, Degradation And Activity In Plants, Meng Xie, Shuxin Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

microRNAs (miRNAs) are important regulators of gene expression. After excised from primary miRNA transcript by dicer-like1 (DCL1, an RNAse III enzyme), miRNAs bind and guide their effector protein named argonaute 1 (AGO1) to silence the expression of target RNAs containing their complementary sequences in plants. miRNA levels and activities are tightly controlled to ensure their functions in various biological processes such as development, metabolism and responses to abiotic and biotic stresses. Studies have identified many factors that involve in miRNA accumulation and activities. Characterization of these factors in turn greatly improves our understanding of the processes related to miRNAs. Here, …

Modifications Of Membrane Lipids In Response To Wounding Of Arabidopsis Thaliana Leaves, Hieu Sy Vu, Rebecca Roston, Sunitha Shiva, Manhoi Hur, Eve Syrkin Wurtele, Xuemin Wang, Jyoti Shah, Ruth Welti

Center for Plant Science Innovation: Faculty Publications

Mechanical wounding of Arabidopsis thaliana leaves results in modifications of most membrane lipids within 6 hours. Here, we discuss the lipid changes, their underlying biochemistry, and possible relationships among activated pathways. New evidence is presented supporting the role of the processive galactosylating enzyme SENSITIVE TO FREEZING2 in the wounding response.

Vegetation-Based Metrics Of Biotic Integrity For Assessing The Ecological Condition Of Wetlands Of Kentucky, Tanner Matthew Morris

Online Theses and Dissertations

Over the last two centuries, wetland acreage across the world has significantly declined due to human disturbances. It has been estimated that Kentucky has lost over 80% of its wetland area. In response to these losses occurring across the United States, the Clean Water Act was passed to halt this dramatic decline and to restore the ecological integrity of waters of the United States. To enforce the Clean Water Act, a number of ecological assessment techniques have been developed to quantify the ecological quality of the waters of the United States. Kentucky recently adopted a rapid method for assessing the …

The Status Of The Genus Taxus In Kentucky, Robert Reed Pace

Online Theses and Dissertations

This study involved a detailed study of the genus Taxus in Kentucky. A thorough examination was conducted, including a review of the literature, examination of field and herbarium specimens from both native and non-native species, microscopic analysis of leaf ultrastructure, chemical analysis of taxane content, and the construction of GIS models to predict the occurrence of the native species. In the review and examination of morphological features, it was found that the best features for separation of the taxa were plant height, the number of the rows of stomata per abaxial leaf band, and the location of papillose cells on …

Characterization Of Novel Sorghum Brown Midrib Mutants From An Ems-Mutagenized Population, Scott E. Sattler, Ana Saballos, Zhanguo Xin, Deanna L. Funnell-Harris, Wilfred Vermerris, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Reducing lignin concentration in lignocellulosic biomass can increase forage digestibility for

ruminant livestock and saccharification yields of biomass for bioenergy. In sorghum (Sorghum bicolor (L.) Moench) and several other C4 grasses, brown midrib (bmr) mutants have been shown to reduce lignin concentration. Putative bmr mutants isolated from an EMS-mutagenized population were characterized and classified based on their leaf midrib phenotype and allelism tests with the previously described sorghum bmr mutants bmr2, bmr6, and bmr12. These tests resulted in the identification of additional alleles of bmr2, bmr6, and bmr12, and, in addition, six bmr …

Assessment Of Rice Self-Sufficiency In 2025 In Eight African Countries, P. A.J. Van Oort, K. Saito, E. Amovin-Assagba, Lenny G.J. Van Bussel, Justin Van Wart, Hugo De Groot, Martin K. Van Ittersum, Kenneth Cassman, M. C.S. Wopereis

Department of Agronomy and Horticulture: Faculty Publications

Most African countries are far from self-sufficient in meeting their rice consumption; in eight countries the production: consumption ratio, ranged from 0.16 to 1.18 in 2012. We show that for the year 2025, with population growth, diet change and yield increase on existing land (intensification), countries cannot become fully self-sufficient in rice. This implies that for the future, a mixture of area expansion and imports will be needed on top of yield gap closure. Further research is needed for identification of most suitable new land for rice area expansion and areas that should be protected.

Patch Burning: Implications On Water Erosion And Soil Properties, Altingul Ozaslan Parlak, Mehmet Parlak, Humberto Blanco-Canqui, Walter H. Schacht, John A. Guretzky, Martha Mamo

Department of Agronomy and Horticulture: Faculty Publications

Patch burning can be a potential management tool to create grassland heterogeneity and enhance forage productivity and plant biodiversity, but its impacts on soil and environment have not been widely documented. In summer 2013, we studied the effect of time after patch burning (4 mo after burning [recently burned patches], 16 mo after burning [older burned patches], and unburned patches [control]) on vegetative cover, water erosion, and soil properties on a patch-burn experiment established in 2011 on a Yutan silty clay loam near Mead, NE. The recently burned patches had 29 ± 8.0% (mean ± SD) more bare ground, 21 …

Productivity And Biological Nitrogen Fixation Of Different Species Of Vetches (Vicia Spp.) Under The Rainfed Conditions Of West Asia, Ali Abd El Moneim, Mohan C. Saxena

IGC Proceedings (1977-2023)

The low rainfall areas of West Asia are characterized by pastoral production system primarily based on small ruminants (sheep and goats). Rangelands serve as the main source of feed. With increasing population, the demand for livestock products has increased. As a consequence, the stocking rates have soared, increasing the pressure on rangelands. Rangeland degradation has therefore been increasing threatening the sustainability of livestock production system and the livelihood of the people dependent on it. Production of additional feed is essential to reduce the pressure on rangelands. Vetches (Vicia spp.) are endemic in the area and can be potential source …

Livestock Production From Grasslands With Improved Management Compared To Traditional Management, Florian Leiber

IGC Proceedings (1977-2023)

The value of traditional versus improved management systems for grassland is discussed. The set target is the persistence of the ecological, economic and social multifunctionality of grasslands and the increase of food output from these areas without increasing parallel requirements for arable crop or energy inputs. Based on the fact that historically traditional systems were stable and sustainable in many cases, while severe damage is faced nowadays, it is argued that lot of improvement should be based on the acknowledgment of successful traditional practises. The challenge might rather be to define improvement as a contemporary development of traditional techniques. The …

Potential Of Forages In Crop Diversification And Crop Rotation, Martin H. Entz, Joanne Thiessen Martens

IGC Proceedings (1977-2023)

Redesign of agricultural systems according to ecological principles has been proposed for the development of sustainable systems. We review a wide variety of ecologically-based crop production practices that focus on forage crops in farming systems and discuss their potential role in enhancing the profitability, environmental sustainability and resilience. Crop-livestock systems that most closely mimic natural systems through appropriate integration of diverse components appear to offer the greatest potential benefits. These systems are more energy efficient and combine high productivity with low ecological footprint. Greater understanding of ecological relationships within crop-livestock systems are required to purposefully and proactively redesign agricultural systems …

Forage Seed Quality: Dormancy, Standards And Quarantine, John G. Hampton

IGC Proceedings (1977-2023)

There are many dimensions to the concept of seed quality. Viable seed which will not germinate when provided with all the requirements for germination is dormant. Forage grasses mostly exhibit non-deep physiological dormancy (PD), while physical dormancy (PY) is common in forage legumes where imbibition is prevented by the seed coat’s impermeability to water (hard seed). Methods for breaking PD and PY to allow germination testing and/or crop establishment are discussed.

In the seed industry seed quality standards are an important feature of quality assurance and may apply for seed production contracts, seed certification, seed sale and seed importing. Standards …

Quality Seed Production And Effective Marketing Systems For Development Of Grasslands, M. Philip Rolston

IGC Proceedings (1977-2023)

Seed quality is defined as (i) maintaining genetic purity using seed certification principles (generation system; isolation; previous cropping history); (ii) achieving high levels of physical purity (especially low weed seed levels) by in field weed control and seed cleaning; (iii) achieving high levels of seed germination at harvest and maintaining germination through the seed supply chain. Seed production systems must not only produce high quality seed but also achieve economic seed yields. Seed crops have to be profitable (by being high yielding) to justify the investment of time and input costs to achieve quality. This in turn requires supporting research …

Scouting Benefits And Developing Innovations In Temperate Grassland To Sustainable Agriculture Production, Walter Ayala, Ethel Barrios, Ignacio Macedo, Jorge Sawchik, José A. Terra

IGC Proceedings (1977-2023)

Agricultural intensification raises concern about land use and future effects to natural resources. The world demand for grain, meat and forest products is increasing constantly. Changes are occurring at large scale, being a compromise for policy makers to contribute to identify opportunities to readdress the productive scenario. There is available technology to reduce impacts, without restricting necessarily productivity. Grasslands provide a large series of economical and ecological benefits to the agricultural systems, being the literature exhaustive in examples. Ley-farming and cover crops technologies are good examples of environmentally sound soil management practices. The society is also worried about an improper …

Evergraze: A Partnership Between Researchers, Farmers And Advisors To Deliver Effective Grassland Management, Warwick B. Badgery, Kate Sargeant, Michael A. Friend, Scott Glyde, Paul Sanford, Ralph Behrendt, Meredith L. Mitchell, Sean Murphy, Angela Avery

IGC Proceedings (1977-2023)

The profitable and sustainable management of livestock production from grassland systems is challenging and it can be difficult to develop a research structure that addresses farmer’s needs and has acceptable rigour and on-ground impact. This paper describes the attributes of research, development and extension (RD&E) programs that are required for a successful partnership between researchers, farmers and advisors. Insights are provided from the EverGraze program that designed, tested and implemented farming systems based on perennial pastures across southern Australia. With this project farmers and advisors were involved in setting research direction, designing experiments, providing strategic guidance over the management of …

Ecologically And Socially Sustainable Livestock Development In Marginal Areas, Ilse Köhler-Rollefson

IGC Proceedings (1977-2023)

“Marginal areas” are perceived as difficult and unproductive landscapes, always under the threat of drought, desertification and poverty. Yet, both dryland and high altitude marginal areas have an extraordinary output of livestock products; in the efficiency of producing human-edible protein they far surpass more fertile areas. This productivity under adverse climatic conditions rests on sophisticated strategies and social institutions developed by pastoral communities to deal with variability in the availability of resources. It depends on the use of animal genetic resources that are adapted to make best use of local vegetation and can cope with seasonal variations in availability. Livestock …

Valuing Variability--New Perspectives On Climate Resilient Dryland Development, Saverio Kratli

IGC Proceedings (1977-2023)

Valuing Variability is a challenge to the view of the drylands as naturally vulnerable to food insecurity and poverty. It argues that improving agricultural productivity in dryland environments is possible by working with climatic uncertainty rather than seeking to control it – a view that runs contrary to decades of development practice in arid and semi-arid lands.

Participatory And Holistic Approaches With Grassland Farmers And Development Of Policies, Alain Peeters

IGC Proceedings (1977-2023)

The world is changing rapidly. Grassland farmers and ruminant livestock breeders will have to adapt to these changing environmental, social and economic conditions. Research can help them at the condition that linear ‘top-down’ technology transfer methods are abandoned for the benefit of participatory and holistic approaches. These approaches classified in the generic term of ‘Farming System Research’ consider farmers as real research partners, and they merge farmer’s and scientist’s ideas with those of other stakeholder types. They combine scientist’s and farmer’s knowledge for creating fast innovations, easily adopted by farmers since farmers themselves contribute to their design and their development. …

Sustainable Grasslands: Resolving Management Options For Livelihood And Environmental Benefits, David R. Kemp, Warwick B. Badgery, David L. Michalk

IGC Proceedings (1977-2023)

To help solve the major issues of improving livelihoods and environmental services, grassland research needs to be evaluated within the context of relevant farm systems. Treatments need to show that they not only have significant effects but that they have effects that are meaningful in the context of the relevant farm system. Research often defines an optimum criterion for management that is a single point, but that is difficult to achieve in practice, especially when there are several components in a grassland system that need to be optimised. It is argued that an appropriate criterion for optimising management is a …

Climate Change Impact And Adaptation In Temperate Grassland And Livestock Industries, Afshin Ghahramani, Andrew D. Moore

IGC Proceedings (1977-2023)

Climate is projected to have negative impact on temperate grassland and livestock productions across the globe. Moderately elevated atmospheric CO₂ in the near future is expected to increase plant photosynthetic rates but this is likely to be limited by soil nitrogen deficits. However, in Australia at least it is unlikely that positive effect of elevated CO₂ on plant production be able to offset the negative impacts of climate change. Currently there is a considerable gap between actual and achievable production and profit in Australian grazing systems and many management and genetic improvements for climate adaptation would operate by …

Climate-Smart Brachiaria For Improving Livestock Production In East Africa: Emerging Opportunities, Sita R. Ghimire, Donald M. G. Njarui, Mupenzi Mutimura, Juan A. Cardoso, Linda Johnson, Elias M. Gichangi, Suliana Teasdale, Kennedy Odokonyero, John Caradus, Idupulapati M. Rao, Appolinaire Djikeng

IGC Proceedings (1977-2023)

Brachiaria grass is an important tropical forage of African origin with desirable attributes of agricultural and environmental significance. Brachiaria has been extensively cultivated as a pasture across the tropics except in its endemic provenance of Africa. In 2013, a collaborative research program was initiated in Kenya and Rwanda with the aim of improving the availability of quality livestock feeds adapted to drought and low fertility soils using Brachiaria. The outcomes sought were increased livestock productivity leading to improved farmer income and the development of seed production opportunities. The program has identified five preferred cultivars, and four of them are currently …

Tropical Grassland Ecosystems And Climate Change, C. R. Babu, Vivek Kr. Choudhary, Vijay Kumar

IGC Proceedings (1977-2023)

Grasses are unique group of flowering plants that form the foundation for the trophic structure in terrestrial communities. The grasses are found in every conceivable habitat where plants can thrive – from sea to deserts and from wetlands to peaks of highest mountains. The grasses form a distinct biome – a major ecological formation in the global classification of vegetation.

Recent Trends In Breeding Of Tropical Grass And Forage Species, J. S. Sandhu, Dinesh Kumar, Vijay Kumar Yadav, Tejveer Singh, R. P. Sah, Auji Radhakrishna

IGC Proceedings (1977-2023)

Germplasm enrichment in major tropical grasses and their characterization for emerging environmental challenges have been major focussed area in the recent past. Breeding efforts in tropical grasses are still limited to few selected species viz. Panicum spp, Cenchrus spp, Pennisetum spp and Bracharia spp and all other grasses use of land races for varietal development through selection have been major source of improvement. The pace of breeding efforts in the tropical grasses have been slowed because of many inherent characteristics viz. apomixis, poor seed set, high photo and thermo sensitivity often creating problem in designing and implementing an effective breeding …