Plant Pathology Commons^™

Strengthening Livelihood Of Rural Farmer Populations Through Improved Grasslands, Sujatha Premaratne, S. C. Somasiri

IGC Proceedings (1977-2023)

This paper reviews the current background of the grassland resource with a purpose of livestock perspective to improve the livelihood of rural farmers. The use of grasslands for livestock rearing by rural farmers has been a long tradition. In climate and vegetation contrast, these grasslands are much more diverse. They are likely to play an economical role in increasing the milk production in many Asian countries. With an increase of human population, the traditional feeding, breeding and surviving habitats for livestock have been acutely restricted in many countries. Therefore, a continued effort is needed to maintain production for sustainable management …

Problems And Prospects Of Grassland Development: Policy Issues, S. Ray Smith

IGC Proceedings (1977-2023)

There are a range of government and non-government policies that affect grassland development around the world. The objective of this paper is to provide examples of successful policies which have been instrumental in the preservation and maintenance of grasslands and to highlight policies which have resulted in negative consequences. This paper will not attempt to provide a complete overview of policies, but instead will provide examples from representative countries. Policies which affect grasslands can be classified into two broad categories: government policies that cover comprehensive landscape issues like the Grassland Household Contract System (GHCS) in China or the Federal Land …

Management Of Grazing Lands Through Educating Communities, D. Ariungerel, Graeme Hand, Annabel Walsh

IGC Proceedings (1977-2023)

The Mongolian steppe is one of the world’s largest grassland and it is an arid to semiarid land with a strong climate gradient. Biodiversity loss leading to desertification and land degradation is estimated to be impacting around 65% of the total area of Mongolia. The preliminary objective of this project was to trial the Positive Deviance Methodology to determine if this method assists herders to design behaviors to reverse this biodiversity loss. This project is a partnership between Mongolian Herders, Mongolian rangeland scientists and Australian based Stipa Native Grasses Association. The Positive Deviance Methodology has five basic steps based around …

Livestock And Local Development: Going To A New Humananimal Relationship, Jean François Tourrand, Laurent Dobremez, Benoit Dedieu, Guillaume Duteurtre, M. G. Piketty, P. Lescoat, B. Hubert

IGC Proceedings (1977-2023)

Along the past ten years, the French National Agency for Research (ANR) has financed projects regarding livestock. Results of five projects were gathered to understand the long-term livestock trends. At the end of the 19th century, animal breeding was oriented towards the production of goods to meet the local, regional, national and global demand, according to the zone. The market gradually became the key-factor to norm both production and consumption. It is now integrating environmental norms and is starting to invest in the social domain. However, this economical vision of animal production does not take into account the other functions …

Genomic Approaches For Dissecting Complex Traits Related To Quality Production Of Range Grasses, Masumi Ebina

IGC Proceedings (1977-2023)

Tropical grasses have been widely used as warm-season forage grasses in the warm temperate zone since the early 20th century because of their high yields; they have also been used as perennial forages in their native tropical areas. Increasing demand for animal production sparked by economic development in tropical countries is requiring breeders to improve native forage grasses in these countries. Considerable efforts have been made to breed accessions with improved characteristics and to develop new cultivars. However, cross-breeding is not common, owing to a lack of genetic information and to complexities related to polyploidy, high sterility rates, outcrossing, and …

Emission Of Green House Gases From Grasslands And Their Mitigation, Prem N. Sharma, Shyam Khadka

IGC Proceedings (1977-2023)

The concentrations of green house gases (GHG) in the atmosphere began in pre-industrial times and it continues to increase. This could result into an alarming increase in temperature of up to 5.4 ^oC by year 2100 due to a net global annual GHG emission of H 4.5-6.5 Gt C equivalent. About 18% of the world’s GHG are contributed by livestock and related activities on grasslands that are spread over almost 35 million Km².These grasslands give livelihood to over a billion people most of who are poor. Twenty to 70% of the land surface area is degrading often …

High-Altitude Grassland Management And Improvement Of Pastoral Livelihoods In The Hindu Kush Himalayan Region, Eklabya Sharma

IGC Proceedings (1977-2023)

The Hindu Kush Himalayan (HKH) region is the largest mountain systems in the world, spanning over 4.3 million km2 and covering 3500 km long fragile environment. Grasslands in the HKH region are the source of livelihoods for approximately 25 to 30 million pastoralists and agro-pastoralists. High altitude grasslands play a significant role in storage and regulation of water; storage of carbon in soil and peat lands; permafrost storage; and stabilization of climate, soil, and nutrients. They foster a rich biodiversity with endemic species of fauna and flora; provide clean air and open spaces for recreational purposes, and bolster a rich …

Planting Date And Variety Selection For Management Of Viruses Transmitted By The Wheat Curl Mite (Acari: Eriophyidae), Anthony J. Mcmechan, Gary Hein

Department of Entomology: Faculty Publications

Wheat is an important food grain worldwide, and it is the primary dryland crop in the western Great Plains. A complex of three viruses (Wheat streak mosaic, Wheat mosaic, and Triticum mosaic viruses) is a common cause of loss in winter wheat production in the Great Plains. All these viruses are transmitted by the wheat curl mite (Aceria tosichella Keifer). Once these viruses are established, there are no curative actions; therefore, prevention is the key to successful management. A study was designed to evaluate preventative management tactics (planting date, resistant varieties) for reducing the impact from this virus complex. …

From Select Agent To An Established Pathogen: The Response To Phakopsora Pachyrhizi (Soybean Rust) In North America, Heather Y. Kelly, Nicholas S. Dufault, David R. Walker, Scott A. Isard, Raymond W. Schneider, Loren J. Giesler, David L. Wright, James J. Marois, Glen L. Hartman

Department of Plant Pathology: Faculty Publications

The pathogen causing soybean rust, Phakopsora pachyrhizi, was first described in Japan in 1902. The disease was important in the Eastern Hemisphere for many decades before the fungus was reported in Hawaii in 1994, which was followed by reports from countries in Africa and South America. In 2004, P. pachyrhizi was confirmed in Louisiana, making it the first report in the continental United States. Based on yield losses from countries in Asia, Africa, and South America, it was clear that this pathogen could have a major economic impact on the yield of 30 million ha of soybean in the …

Pilg Is Involved In The Regulation Of Twitching Motility And Antifungal Antibiotic Biosynthesis In The Biological Control Agent Lysobacter Enzymogenes, Xue Zhou, Guoliang Qian, Yuan Chen, Liangcheng Du, Fengquan Liu, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

Lysobacter enzymogenes strain C3 is a gliding bacterium which produces the antifungal secondary metabolite heat-stable antifungal factor (HSAF) and type IV pilus (T4P) as important mechanisms in biological control activity against fungal pathogens. To date, the regulators that control HSAF biosynthesis and T4P-dependent twitching motility in L. enzymogenes are poorly explored. In the present study, we addressed the role of pilG in the regulation of these two traits in L. enzymogenes. PilG of L. enzymogenes was found to be a response regulator, commonly known as a component of a two-component transduction system. Mutation of pilG in strain C3 abolished its …

Fungicide And Herbicide Effects On Gray Leaf Spot In Nebraska Field Corn, 2014, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was to compare fungicide and herbicide treatments for gray leaf spot (GLS) efficacy. Corn was grown under normal, irrigated agronomic practices at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8% organic matter and the previous crop was corn. Reduced tillage was performed prior to planting. Corn (DKC 64-83 RIB, moderately susceptible to GLS) was planted at approximately 34,000 seed/A on 2 May. Seven treatments were arranged in a randomized complete block design with six replications. . . . Treatments applied at V8 or R1 …

Characterizing The Agronomic Benefits Of Solatenol Fungicide Tank-Mixture Applications In Nebraska Field Corn, 2014, J. D. Harbour, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

The objective of the trial was characterize Solatenol fungicide tank mix programs and compare performance to Quilt Xcel for gray leaf spot (GLS) efficacy. Corn was grown under normal, irrigated agronomic practices at the South Central Ag Lab near Clay Center, NE. Soils were a silt loam with 6.7 pH and 1.8 % organic matter. Reduced tillage was performed to the field prior to planting. Corn (G11U58-3111 susceptible to GLS) was planted at approximately 34,000 seed/A on 20 May. Eight treatments were arranged in a randomized complete block design with six replications. . . . Fungicides applied at V5, R1, …

A Spectrum Of Hrt-Dependent Hypersensitive Responses Elicited By The 52 Amino Acid N-Terminus Of Turnip Crinkle Virus Capsid Protein And Its Mutants, Sung-Hwan Kang, Feng Qu, Thomas Jack Morris

Department of Plant Pathology: Faculty Publications

The capsid protein (CP) of turnip crinkle virus (TCV) is the elicitor of hypersensitive response (HR) and resistance mediated by the resistance protein HRT in the Di-17 ecotype of Arabidopsis. Here we identified the N-terminal 52-amino-acid R domain of TCV CP as the elicitor of HRT-dependent HR in Nicotiana benthamiana. Mutating this domain at position 6 (R6A), but not at positions 8 (R8A) or 14 (G14A), abolished HR in N. benthamiana. However, on Di-17 Arabidopsis leaves only R8A R domain elicited visible epidermal HR. When incorporated in infectious TCV RNAs, R8A and G14A mutations exerted dramatically different effects …

How Do Free-Living, Lerp-Forming, And Gall-Inducing Aphalaridae (Hemiptera: Psylloidea) Affect The Nutritional Quality Of Eucalyptus Leaves?, Anamika Sharma, James Allen, Soundararajan Madhavan, Anantanarayanan Raman, Gary S. Taylor, Murray J. Fletcher

Department of Biochemistry: Faculty Publications

About 380 described species of Psylloidea occur on Eucalyptus in Australia. These show differences in diversification, feeding behavior, and apparent patterns of development. We analyzed the quality of nutrients used by three species of Aphalaridae belonging to different feeding guilds on three species of Eucalyptus. We evaluated the quantity and quality of total nonstructural carbohydrates (TNC), δ¹³C and δ¹⁵N isotope ratios, amino acids, and fatty acids. In general, TNC levels were greater in infested leaves than in uninfested leaves of the three species of Eucalyptus. TNC levels in the leaves of E. macrorhyncha F. …

Generation Of An Attenuated, Cross-Protective Pepino Mosaic Virus Variant Through Alignment-Guided Mutagenesis Of The Viral Capsid Protein, Godwill M. Chewachong, Sally A. Miller, Joshua J. Blakeslee, David M. Francis, Thomas Jack Morris, Feng Qu

School of Biological Sciences: Faculty Publications

Mild variants of many viruses are able to protect infected plants from subsequent invasion by more severe variants of the same viruses through a process known as cross-protection. In the past, the cross-protective viral variants were commonly derived from mild field isolates that were sometimes genetically heterogeneous, providing variable levels of crossprotection. Here, we report a novel approach to rapidly generate crossprotective variants of the tomato-infecting Pepino mosaic virus (PepMV) independently of the availability of mild field isolates. Our approach sought to attenuate PepMV by mutating less conserved amino acid residues of the abundantly produced capsid protein (CP). These less-conserved …

Susceptibility Of Northern Corn Rootworm Diabrotica Barberi (Coleoptera: Chrysomelidae) To Mcry3a And Ecry3.1ab Bacillus Thuringiensis Proteins, Isaac O. Oyediran, Phillip Matthews, Narendra Palekar, Wade French, Jared Conville, Tony Burd

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The susceptibility of the northern corn rootworm Diabrotica barberi (Smith & Lawrence) to mCry3A and eCry3.1Ab proteins derived from Bacillus thuringiensis (Bt) was determined using a diet bioassay. Northern corn rootworm neonates were exposed to different concentrations of mCry3A and eCry3.1Ab, incorporated into artificial diet. Larval mortality was evaluated after 7 d. The mCry3A and eCry3.1Ab proteins were found to be toxic to the northern corn rootworm larvae. The LC₅₀ and LC₉₉ values for mCry3A were 5.13 and 2482.31 μg/mL, respectively. For eCry3.1Ab, the LC₅₀ and LC₉₉ values were 0.49 and 213.01 μg/mL. Based on the …

Occurrence Of Arbuscular Mycorrhizal Fungi And Fusarium In Tc Banana Rhizosphere Inoculated With Microbiological Products In Different Soils In Kenya, R. W. Mukhongo, M. A. Kavoo-Mwangi, M. E. Kahangi, E. M. Ateka, A. B. Were, J. R. Okalebo, M. E. Mutegi, K. E. Mwangi, T. T. Tepeni, K. S. Njuguini, J. M. Onguso, S. A. Okoth, J. M. Jefwa

All Peer-Reviewed Publications

The impact of microbiological commercial products (PHC Biopak, Rhizatech and ECO-T) on the occurrence of mycorrhizae and Fusarium in the rhizosphere of tissue culture banana (Gros Mitchel cv.) was assessed. Tissue cultured banana plantlets were inoculated with PHC Biopak (Bacillus), Rhizatech (mycorrhiza) and ECO-T (T. harzianum) under greenhouse conditions using a completely randomized design in a Vertisol, Rhodic Ferralsol and Humic Nitisol sampled from the major banana growing regions in Kenya. Potted plants were later established under field conditions in the three agro ecological zones. Roots and soils sampled at end of potting and at flowering were assessed for AM …

Bioethanol: Feedstock Alternatives, Pretreatments,Lignin Chemistry, And The Potential For Green Value-Added Lignin Co-Products, Ruben Michael Ceballos, N. A. Batchenkova, M.K. Y. Chan, A. X. Duffing-Romero, A. E. Nelson, S. Man

Biological Sciences Faculty Publications and Presentations

Major challenges still exist in the cost-competitive production of cellulosic ethanol. Lignocellulose deconstruction using physiochemical pretreatments continues to be the most efficient way to remove lignin and expose cellulose for enzyme-mediated sugar reduction. Recent interest in the development of “value-added” lignin co-products and the desire to reduce the use of hazardous materials has prompted a resurgence of interest in alternative lignocellulosic feedstock and research into environment-friendly biological pretreatments. This article provides an overview of bioethanol processes and economics, standard and alternative feedstocks, physiochemical and biological pretreatments, and lignin chemistry. The chemistry and mode of action of ligninolytic and cellulolytic enzymes …

Managing Threats To The Urban Forest: From Dutch Elm Disease To Emerald Ash Borer - Learning From Experience, Christopher J. Borman

Doctor of Plant Health Program: Dissertations and Student Research

The urban forest provides important essential services to all municipalities; however, its value is often overlooked. The urban forest contributes to energy savings, environmental benefits, psychological well-being, and social benefits. Managing the urban forest in a sustainable manner is important if we wish to benefit from these services well into the future. Reliable management techniques have been created through previous experiences with pests, and these should be utilized and improved for use on urban forests.

American elm (Ulmus americana L.) was once a major component of the urban forests of North America. In 1927, Dutch elm disease (DED) was …

Mono- And Digalactosyldiacylglycerol Lipids Function Nonredundantly To Regulate Systemic Acquired Resistance In Plants, Qing-Ming Gao, Keshun Yu, Ye Xia, M. B. Shine, Caixia Wang, Duroy Navarre, Aardra Kachroo, Pradeep Kachroo

Plant Pathology Faculty Publications

The plant galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) have been linked to the anti-inflammatory and cancer benefits of a green leafy vegetable diet in humans due to their ability to regulate the levels of free radicals like nitric oxide (NO). Here, we show that DGDG contributes to plant NO as well as salicylic acid biosynthesis and is required for the induction of systemic acquired resistance (SAR). In contrast, MGDG regulates the biosynthesis of the SAR signals azelaic acid (AzA) and glycerol-3-phosphate (G3P) that function downstream of NO. Interestingly, DGDG is also required for AzA-induced SAR, but MGDG is not. Notably, …