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A Non-Capsid Protein Associated With Unencapsidated Virus Rna In Barley Infected With Barley Stripe Mosaic Virus, Myron K. Brakke, E. M. Ball, W. G. Langenberg

Department of Plant Pathology: Faculty Publications

Barley tissue with an acute systemic infection of barley stripe mosaic virus contained a large amount of unencapsidated virus RNA which was stable in extracts made in ribosome isolation buffer. The virus RNA in ribosome preparations sedimented in a broad band at 80S to 100S in sucrose gradients, which is less than the virion sedimentation rate of 180S to 200S. A protein of apparent M_r 60 000, which sedimented with the virus RNA, was present in ribosome extracts from infected plants but absent from those from uninfected plants. The protein is probably a virus protein because its apparent molecular …

Chlorophyll, Chloroplast Ribosomal Rna, And Dna Are Reduced By Rarley Stripe Mosaic Virus Systemic Infection, Myron K. Brakke, J. L. White, R. G. Samson, Jay Joshi

Department of Plant Pathology: Faculty Publications

Barley stripe mosaic virus became systemic 3 days alter inoculation of barley plants in the two-leaf stage. The first leaf to show mosaic was leaf 3. which was 4.5 cm long at 3 days after inoculation when it was invaded by virus. Since all of Ieaf 3 showed mosaic, the events leading to mosaic occurred during cell expansion and after cell division. which is limited to the basal centimeter of young cereal leaves. Molecular changes associated with mosaic formation included a 509, reduction in chloroplast ribosomal RNA and chlorophyll, expressed as amount per unit DNA, in young leaves with an …

Comparisons Of Mitochondrial Dna From The Sibling Species Heterodera Glycines And H. Schachtii, A. D. Radice, Thomas O. Powers, Laurie J. Sandall, R. D. Riggs

Department of Plant Pathology: Faculty Publications

Restriction fragment patterns of mitochondrial DNA from sibling species of cyst nematodes Heterodera glycines and H. schachtii were examined. Fourteen restriction endonucleases recognizing four, five, and six base-pair sequences yielded a total of 90 scorable fragments of which 10% were shared by both species. Mitochondrial genome sizes for H. glycines and H. schachtii were estimated to be 22.5-23.5 kb and 23.0 kb, respectively. A single wild type mitochondrial genome was identified in all populations of H. glycines examined, although other mitochondrial genomes were present in some populations. The H. schachtii genome exhibited 57 scorable fragments, compared with 33 identified in …

Estimation Of Genetic Divergence In Meloidogyne Mitochondrial Dna, Thomas O. Powers, Laurie J. Sandall

Department of Plant Pathology: Faculty Publications

Restriction fragments from purified mitochondrial DNA can be readily detected following rapid end-labeling with [α-³²P] nucleoside triphosphates and separation by gel electropboresis. Mitochondrial DNA from 12 populations of Meloidogyne species was digested with 12 restriction enzymes producing more than 60 restriction fragments for each species. The mitochondrial genome of M. arenaria is the most genetically distinct of the four species compared. M. arenaria shows approximately 2.1-3.1% nucleotide sequence divergence from the mitochondrial genomes of M. javanica, M. incognita, and M. hapla. Among the latter three species, interspecific estimates of sequence divergence range from 0.7 to …

Concentration Of Maize Chlorotic Mottle Virus Increased In Mixed Infections With Maize Dwarf Mosaic Virus, Strain B, Karen-Beth Goldberg, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

The concentration of maize chlorotic mottle virus (MCMV) was up to 5.4 times higher in plants infected with both MCMV and maize dwarf mosaic virus. strain R (MDMV-BE. rhan in plants infected with MCMY only. The concentration of MDMV-B was the same in doubly and singly infected plants. Plants infected with both viruses had a reduced level of chlorophyIl and a lower than normal ratio of chloroplast to cytoplasmic rRNA. Purified MCMV had an extinction coefficient of 6.7 cm² mg^-1 at 260 nm, an absorption maximum at 258 nm, minimum at 240 nm, and 25% RNA.

Infection Rate Of Tall Fescue With Acremonium Coenephialum, B. J. Hankins, Terry Kirkpatrick

Journal of the Arkansas Academy of Science

No abstract provided.

Virus Disease Of Small Fruits, R. H. Converse

School of Biological Sciences: Faculty Publications

This illustrated handbook was compiled by international authorities on virus and viruslike diseases of small fruits. Crops covered are in the plant genera Fragaria (strawberry), Vaccinium (blueberry and cranberry), Ribes (currant and gooseberry), and Rubus (blackberry and raspberry). The history, geographic distribution, importance, symptoms, transmission, cause, detection, and control of virus and viruslike diseases attacking these crops are discussed.

The Pollen Exostructure Of Striga (Scrophulariaceae), Mark A. Deleonardis

Biological Sciences Theses & Dissertations

In this survey, the pollen exostructure of 13 Striga species was examined using light microscopy and scanning electron microscopy. Two of the 13 species were also observed by transmission electron microscopy to assess major differences in exine composition. Striga pollen is consistently spherical to oblate, isopolar, tectate, and three or four colpate. Sculpturing may be psilate, psilate-perforate, finely rugulate, or coarsely rugulate. The equatorial width of the species surveyed ranged from 15 to 30 micrometers. It is concluded that variation in Striga pollen sculpturing, aperture structure, and size support the current taxonomy of the genus.

Differential Effects Of Lithium Chloride On In Vitro Growth Of Clavibacter Michiganense Subsp. Nebraskense Depending Upon Inoculum Source, Mary L. Smidt, Anne K. Vidaver

Department of Plant Pathology: Faculty Publications

The bacterium Clavibacter michiganense subsp. nebraskense (Corynebacterium michiganense subsp. nebraskense) was grown in broth cultures and inoculated into corn plants. The plating efficiency of cells from broth cultures was essentially the same on nutrient broth-yeast extract and the semiselective medium for this bacterium, CNS. However, when cells were isolated from Goss bacterial wilt- and blight-infected corn, very few were recovered on CNS compared with the amount recovered on nutrient broth-yeast extract agar. When lithium chloride was omitted from the CNS, recoveries from infected corn were nearly the same as on nutrient broth-yeast extract agar. No other ingredient of CNS …

Restriction Endonuclease Activity Induced By Pbcv-1 Virus Infection Of A Chlorella-Like Green Alga, Yuannan Xia, Dwight Burbank, Lothar Uher

Department of Plant Pathology: Faculty Publications

An enzyme was isolated from a eucaryotic, Chlorella-like green alga infected with the virus PBCV-1 which exhibits type I1 restriction endonuclease activity. The enzyme recognized the sequence GATC and cleaved DNA 5' to the G. Methylation of deoxyadenosine in the GATC sequence inhibited enzyme activity. In vitro the enzyme cleaved host Chlorella nuclear DNA but not viral DNA because host DNA contains GATC and PBCV-1 DNA contains GmATC sequences. PBCV-1 DNA is probably methylated in vivo by the PBCV-1-induced methyltransferase described elsewhere (Y. Xia and J. L. Van Etten, Mol. Cell. Biol. 6:144-1445). Restriction endonuclease activity was first detected …

Dna Methyltransferase Induced By Pbcv-1 Virus Infection Of A Chlorella-Like Green Alga, Yuannan Xia, James L. Van Etten

Department of Plant Pathology: Faculty Publications

A DNA methyltransferase was isolated from a eucaryotic, Chlorella-like green alga infected with the virus PBCV-1. The enzyme recognized the sequence GATC and methylated deoxyadenosine solely in GATC sequences. Host DNA, which contains GATC sequences, but not PBCV-1 DNA, which contains GmATC sequences, was a good substrate for the enzyme in vitro. The DNA methyltransferase activity was first detected about 1 h after viral infection; PBCV-1 DNA synthesis and host DNA degradation also began at about this time. The appearance of the DNA methyltransferase activity required de novo protein synthesis, and the enzyme was probably virus encoded. Methylation of …

Restriction Endonuclease Activity Induced By Pbcv-1 Virus Infection Of A Chlorella-Like Green Alga, Yuannan Xia, Dwight Burbank, Lothar Uher, Dietrmar Rabussay, James L. Van Etten

Department of Plant Pathology: Faculty Publications

An enzyme was isolated from a eucaryotic, Chlorella-lie green alga infected with the virus PBCV-1 which exhibits type II restriction endonuclease activity. The enzyme recognized the sequence GATC and cleaved DNA 5' to the G. Methylation of deoxyadenosine in the GATC sequence inhibited enzyme activity. In vitro the enzyme cleaved host Chlorella nuclear DNA but not viral DNA because host DNA contains GATC and PBCV-1 DNA contains G^mATC sequences. PBCV-1 DNA is probably methylated in vivo by the PBCV-1-induced methyltransferase described elsewhere (Y. Xia and J. L. Van Etten, Mol. Cell. Biol. 6:1440-1445). Restriction endonuclease activity was …

Species-Specific Restriction Site Polymorphism In Root-Knot Nematode Mitochondrial Dna, Thomas O. Powers, E. G. Platzer, Bradley C. Hyman

Department of Plant Pathology: Faculty Publications

Research was initiated to physically characterize the mitochondrial genomes of several Meloidogyne spp. and host-races, to address questions regarding their systematics and dispersal, and to assess the possibility of developing molecular diagnostics for these nematodes. Techniques were developed for purification and rapid detection of mitochondrial DNA from root-knot nematodes. Mitochondrial DNAs among Meloidogyne spp. were demonstrated to exhibit extensive divergence. The potential for using the rapidly diverging mitochondrial genomes as a diagnostic assay for M. incognita, M. hapla, M. arenaria, and M. javanica is discussed.

Yellow Spot Of Wheat, R Loughman, J. M. Wilson, R. E. Wilson

Journal of the Department of Agriculture, Western Australia, Series 4

Yellow spot is a serious leaf disease of wheat in Western Australia. It also occurs in Queensland, New South Wales and South Australia. Yellow spot can appear as a severe leaf blight but generally the disease does not have the rapid epidemic development of wheat rust diseases. It builds up more slowly and is not as obvious in the crop, while caising appreciable yield loss.

Transposon Mutagenesis And Excision Of R' Plasmids By Conjugative, Chimeric Plasmid Puw942 In Extra-Slow-Growing Rhizobium Japonicum Strains, Alahari Arunakumari, Anne K. Vidaver

Department of Plant Pathology: Faculty Publications

Transposons Tn501 (specifying mercury resistance) and Tn7 (specifying resistance to trimethoprim and streptomycin) were introduced into extra-slow-growing Rhizobium japonicum by conjugal transfer of the 82 kilobase chimeric plasmid pUW942. Mercury-resistant transconjugants were obtained at a frequency of 10^-7 to 10^-9. The transfer frequency of streptomycin resistance was lower than that of mercury resistance, and Tn7 was relatively unstable. pUW942 was not maintained as an autonomously replicating plasmid in R. japonicum strains. However, some of the Hg^r transconjugants from the RJ19FY, RJ17W, and RJ12S strains acquired antibiotic markers of the vector plasmid pUW942. Southern hybridization of plasmid …

Population Dynamics Of Sugar Beets, Rhizoctonia Solani, And Laetisaria Arvalis: Responses Of A Host, Plant Pathogen, And Hyperparasite To Perturbation In The Field, Michael F. Allen, Michael G. Boosalis, Eric D. Kerr, Anne E. Muldoon, Harold J. Larsen

Department of Plant Pathology: Faculty Publications

Rhizoctonia solani causes crown rot of sugar beets, a severe disease that has destroyed up to 60% of the plants in a test field in western Nebraska. Laetisaria arvalis, a natural hyperparasite of Rhizoctonia spp., was isolated from fields in western Nebraska. To test for the potential for biological control of R. solani, in November 1980 (following harvest) we applied various combinations of a nematicide (Telone II; Dow Chemical Co.), a nutrition source (sugar beet pulp), and an inoculum of L. arvalis in a randomized block design. Populations of R. solani, L. arvalis, and sugar beets were …

Synthesis And Localization Of A Development-Specific Protein In Sclerotia Of Sclerotinia Sclerotiorum, Geraldine Russo, James L. Van Etten

Department of Plant Pathology: Faculty Publications

A development-specific protein (SSP) makes up about 35 to 40% of the total protein in sclerotia of the fungus Sclerotinia sclerotiorum. The protein consists of three charge isomers, with one isomer making up 80 to 90% of the total. In vitro translation of poly(A)⁺ RNA isolated from cells in early stages of sclerotia formation revealed that 44% of the amino acids incorporated was into SSP. In vivo- and in vitro-synthesized forms of SSP migrated at identical rates on both isoelectric focusing and denaturing polyacrylamide gels, indicating that SSP was not synthesized as a larger precursor. This was significant …

A Survey For Viruses From Fresh Water That Infect A Eucaryotic Chlorella-Like Green Alga, James L. Van Etten, Cecil H. Van Etten, Jeffrey Johnson, Dwight Burbank

Department of Plant Pathology: Faculty Publications

Viruses which formed plaques on lawns of a eucaryotic, chlorella-like green alga were detected in 37% of the 35 freshwater samples surveyed. Virus populations, monitored in seven locations, fluctuated both qualitatively and quantitatively over an 8-month period.

The Isolation, Property Analysis And Determination Of In Planta Growth Ability Of Extracellular Polysaccharide Mutants Of Corynebacterium Michiganense Pv Insidiosum, Mary C. Paschke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Corynebacterium michiganense pv insidiosum, the organism responsible for bacterial wilt of alfalfa, produces an extracellular polysaccharide (EPS) that has been linked to its virulence. The EPS is composed of three different-sized molecules (components I, II and III). It has been demonstrated that this EPS accumulates in the vascular system of infected plants and causes disruption of the flow of water.

The importance of EPS to the survival and pathogenicity of C.m. pv insidiosumis not known. In order to begin assessing the value of EPS, mutant strains that are EPS-deficient were isolated after UV mutagenisis. Analysis by gel filtration …

Sequence Relationships Among Soil-Borne Wheat Mosaic Virus Rna Species And Terminal Structures Of Rna Ii, Y. H. Hsu, M. K. Brakke

Department of Plant Pathology: Faculty Publications

Gel-separated RNAs of the wild-type (WT), Lab 1 and Lab 2 isolates of soil-borne wheat mosaic virus (SBWMV) were transferred to nitrocellulose filters and hybridized with specific cDNA. RNA I, but not RNA II, from all three SBWMV isolates hybridized to cDNA copied from SBWMV WT RNA I. RNA II from all three SBWMV isolates hybridized to cDNA copied from SBWMV WT RNA II, confirming the hypothesis that the Lab 1 and Lab 2 isolates arose by deletion of part of RNA II of WT virions. RNA I1 from SBWMV WT (0∙5L RNA) or from SBWMV Lab 1 (0.35L RNA) …

Germination And Host Range Of Branched Broomrape (Orobanche Ramosa) From Texas, Robert D. Coffin

Biological Sciences Theses & Dissertations

The effect of temperature on the germination of Orobanche ramosa L., branched broomrape, was investigated by dividing the physiological stages leading to germination into discrete events: pretreatment, a period when the seed becomes receptive to stimulant, and posttreatment, when stimulant application (GR-24) induces germination. Seed was pretreated and posttreated at 16 different temperature combinations. Optimal pretreatment was at 15°C and 18°C, maximum posttreatment at 18°C. Highest germination was obtained by pretreating and posttreating seed at 18°C, lowest at 24°C. The effect of different pretreatment regimes was tested. Seeds were pretreated over moist filter paper and in soil for Oto …

Source Of Inoculum, Yield And Quality Of Tomato As Affected By Leveillula Taurica, Wayne B. Jones

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tomato transplant stock from southern Nevada served as a source of inoculum and developed disease symptoms of tomato powdery mildew approximately three weeks before Utah-grown transplants. Plants from Nevada and Utah were equally infected seven weeks after planting and no differences in severity or yield were detected at the end of the season due to rapid spread of the fungus. Tomato yields were reduced ca 40% in check plots when compared to plots treated with triadimefon, propiconazol or sulfur. The amount of sunburned fruit in check plots was three to four times greater than in plots where the disease was …

Proceedings Of The 11th Annual Meeting, Southern Soybean Disease Workers (March 27-29, 1984, Ft. Walton Beach, Florida): Economics Of Soybean Disease, H. Jack Walters, Richard E. Stuckey, Edwin F. Koldenhoven, Murray E. Nance, James D. Arnett

Southern Soybean Disease Workers: Conference Proceedings

Contents

1984 Southern Soybean Disease Workers Officers

1984 Southern Soybean Disease Workers Program Committee

1984 Southern Soybean Disease Workers Committee Chairmen

Workshop

Diagnosing early season soybean disorders. D Stuckey and A Wrather

General session

Presidential address. HJ Walters

Southern United States Soybean Disease Loss Estimate for 1983. Southern Soybean Disease Workers, Soybean Disease Loss Estimate Committee. RP Mulrooney

Soybean nematodes. R Dunn presiding

A New Publication on the Soybean Cyst Nematode. WF Moore

Soybean Cultivars and Development of Populations of Meloidogyne incognita in Soil: A Concept of Tolerance. R Rodríguez-Kábana and DB Weaver

A Comparison of Soybean Cultivars for …

Results Of The Thirteenth International Winter Wheat Performance Nursery Grown In 1981, S. L. Kuhr, C. J. Peterson, V. A. Johnson, P. J. Mattern, J. W. Schmidt

Nebraska Agricultural Experiment Station: Historical Research Bulletins

This is the thirteenth report of results from an International Winter Wheat Performance Nursery (IWWPN) organized in 1968 by the Nebraska Agricultural Experiment Station in cooperation with the Agricultural Research Service (ARS), U. S. Department of Agriculture, under contract number AID/ta-C-1093 with the U. S. International Development Corporation, Agency for International Development. The Nursery was designed to (1) test the adaptation and stability of winter wheat cultivars in a range of latitudes, daylengths, fertility conditions, water management regimes, and disease complexes; (2) identify superior winter cultivars to serve as recipient genotypes for high protein and high lysine genes; (3) test …

Book Review: Plant Infectious Agents, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

This is not the book to go to for exhaustive coverage or detailed experimental protocol, but it is excellent for a concise version of recent developments in the molecular biology of plant viruses.

Two Purified Rnas Of Soil-Borne Wheat Mosaic Virus Are Needed For Infection, Yukio Shirako, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

RNAs of soil-borne wheat mosaic virus (SBWMV) from virions 281 nm, 138 nm and 92 nm long (designated here by relative lengths as 1∙0L, 0∙SL and 0∙35L, respectively), were isolated and purified by three cycles of sucrose density gradient centrifugation. Infectivity assays with these RNAs proved the bipartite nature of SBWMV, the combination of 1∙0L and either 0∙5L or 0∙35L RNAs being required for infection and for multiplication of progeny viruses. The 0∙5L RNA underwent deletion mutation, producing smaller variants with various sizes, of which 0∙4L and 0∙35L RNAs were confirmed to be functional in combination with 1∙0L RNA. The …

A 'Natural Herbicide' Against Calotrope?, A H. Cheam

Journal of the Department of Agriculture, Western Australia, Series 4

Buffel grass produces a chemical compound which is toxic to the growth of calotrope seedlings, a declared weed in Western Austrsalia north of the 26th parallel. This new discovery id highly significant in view of the increasing emphasis now placed on weed management as opposed to weed control and the desire to use fewer pesticides.

Mutations, The Abberant Ratio Phenomenon, And Virus Infection Of Maize, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

Viruses interact genetically in various ways with bacterial and animal hosts, e.g. by lysogeny in bacteriophage and by incorporating a DNA copy of retrovirus RNA into the host genome. These phenomena lead to mutations, to the transfer of host genes by viruses, and to latent viruses being transmitted from generation to generation essentially as host genes. In contrast, there are no known examples of the incorporation of viral genomes into plant DNA.

Spontaneous Deletion Mutation Of Soil-Borne Wheat Mosaic Virus Rna Ii, Yukio Shirako, Myron K. Brakke

Department of Plant Pathology: Faculty Publications

The wild-type (WT) isolate of soil-borne wheat mosaic virus has two species of rodshaped virions 281 nm and 138 nm in length, which are designated as virions 1∙0L and 0∙5L, respectively. We reported previously that virions shorter than 0∙5L arose in assay plants inoculated with separated and recombined 1∙0L RNA and 0∙5L RNA and suggested that these short virions were caused by deletion mutation of 0∙5L RNA. We now report that these short virions arose after a period of several months in wheat plants that had been inoculated manually with unpurified WT isolate, and also when plants infected naturally in …

Biosynthesis And Degradation Of Storage Protein In Spores Of The Fungus Botryodiplodia Theobromae, Gary Petersen, Kurt Dahlberg, James L. Van Etten

Department of Plant Pathology: Faculty Publications

Muiridin, a spore-specific protein of the fungus Botryodiplodia theobromae, comprises about 25% of the mature pycnidiospore protein. It has an apparent molecular weight of 16,000 to 17,000 and is rich in glutamine, asparagine, and arginink. Muiridin is synthesized in developing spores via a precursor with an apparent molecular welght of 24,000. Two other polypeptides present in young developing spores with apparent molecular weights of 18,000 and 15,000 are immunologically related to muiridin. We propose a pathway for muiridin synthesis. Muiridin is actively degraded during the germination of spores from 30-day old cultures. This degradation is independent of exogenous amino …