Life Sciences Commons^™

Management Of Nematodes Associated With Tobacco And Sweet Potato Using Non-Fumigant Approach, Md Shah Alam

All Theses

Tobacco and sweet potato are attacked by several species of plant-parasitic nematodes leading to substantial yield losses. Because host-plant resistance is lacking in commercial cultivars and other common methods of nematode management either have low efficacy or pose adverse effects to the environment, controlled environment studies were conducted to evaluate the efficacy of non-fumigant chemical and biological nematicides against Meloidogyne enterolobii on tobacco and Rotylenchulus reniformis on sweet potato. Results suggest that fluensulfone was the most effective in suppressing M. enterolobii in tobacco, followed by oxamyl and fluopyram. The biological Burkholderia derived biological nematicide did not suppress the nematode population. …

Fungicide Sensitivity, Race Structure, And Host Pathogenicity Of Phytophthora Nicotianae In Tennessee And North Carolina, Taylor Giovanna Miller

Masters Theses

Phytophthora nicotianae, a hemibiotrophic oomycete, is the causal agent of disease of over 300 hosts, notably tobacco, tomato, citrus, strawberry, and ornamentals. Black shank of tobacco is a devastating disease that can result in up to 100% yield loss if left untreated, and buckeye rot of tomato compromises the marketability and yield of fruit impacted by P. nicotianae. Black shank and buckeye rot have been reported throughout the state of Tennessee, and the goal of this work was to analyze fungicide sensitivity of P. nicotianae isolated from tobacco and tomato, characterize the race structure of P. nicotianae, …

Characteristics Of Cercospora Nicotianae With Reduced Sensitvity To Azoxystrobin, William Barrett Barlow

Theses and Dissertations--Plant Pathology

Burley and dark tobacco production are important to agriculture in Kentucky, worth $145.1 and $94.4 million in 2020, respectively. The price received for a tobacco crop is influenced by leaf quality, determined by multiple characteristics including leaf damage. Frogeye leaf spot (FLS), caused by Cercospora nicotianae, has historically been a minor disease of tobacco. However, when FLS infections reach the upper canopy of tobacco, lesions are seen as damage that negatively influence leaf quality. Fungicides are regularly used to manage foliar diseases of tobacco, and the only systemic fungicide active ingredient labeled for tobacco is azoxystrobin. Azoxystrobin belongs to the …

Inhibition Of Fusarium Oxysporum F. Sp. Nicotianae Growth By Phenylpropanoid Pathway Intermediates, Timothy E. Shull, Jasmina Kurepa, Robert D. Miller, Natalia Martinez-Ochoa, Jan A. Smalle

Plant and Soil Sciences Faculty Publications

Fusarium wilt in tobacco caused by the fungus Fusarium oxysporum f. sp. nicotianae is a disease‑management challenge worldwide, as there are few effective and environmentally benign chemical agents for its control. This challenge results in substantial losses in both the quality and yield of tobacco products. Based on an in vitro analysis of the effects of different phenylpropanoid intermediates, we found that the early intermediates trans‑cinnamic acid and para‑coumaric acid effectively inhibit the mycelial growth of F. oxysporum f. sp. nicotianae strain FW316F, whereas the downstream intermediates quercetin and caffeic acid exhibit no fungicidal properties. Therefore, our in …

Determination Of Vegetative Development And Flower Effect Of Transgenic Nicotiana Tabacum, Hasan Pinar, Aydin Uyun, Semih Yilmaz, Nedim Mutlu, Amitava Mitra

Department of Plant Pathology: Faculty Publications

Species and varieties in the Nicotiana genus may respond differently to photoperiodism in terms of flowering time control. These are classified as short day, neutral day and long day plants. One of these, Nicotiana tabacum cv. The Xanthi nc is a genotype which can flowering on a long day. But the genotype Kanamycin resistance can open its flowers in January when the resistance gene is transferred to the plant. On the other hand, the effect of rootstock to scion in plant species is very important. One of the issues raised is whether the transgenic plant in the rootstock is effect …

Co-Opting Atp-Generating Glycolytic Enzyme Pgk1 Phosphoglycerate Kinase Facilitates The Assembly Of Viral Replicase Complexes, K. Reddisiva Prasanth, Chingkai Chuang, Peter D. Nagy

Plant Pathology Faculty Publications

The intricate interactions between viruses and hosts include exploitation of host cells for viral replication by using many cellular resources, metabolites and energy. Tomato bushy stunt virus (TBSV), similar to other (+)RNA viruses, induces major changes in infected cells that lead to the formation of large replication compartments consisting of aggregated peroxisomal and ER membranes. Yet, it is not known how TBSV obtains the energy to fuel these energy-consuming processes. In the current work, the authors discovered that TBSV co-opts the glycolytic ATP-generating Pgk1 phosphoglycerate kinase to facilitate the assembly of new viral replicase complexes. The recruitment of Pgk1 into …

Genome Sequence Variation In The Constricta Strain Dramatically Alters The Protein Interaction And Localization Map Of Potato Yellow Dwarf Virus, Chanyong Jang, Renyuan Wang, Joseph Wells, Fabian Leon, Mark Farman, John Hammond, Michael M. Goodin

Plant Pathology Faculty Publications

The genome sequence of the constricta strain of Potato yellow dwarf virus (CYDV) was determined to be 12 792 nt long and organized into seven ORFs with the gene order 3′-N-X-P-Y-M-G-L-5′, which encodes the nucleocapsid, phospho, movement, matrix, glyco, and RNA-dependent RNA polymerase proteins, respectively, except for X, which is of unknown function. Cloned ORFs for each gene, except L, were used to construct a protein interaction and localization map (PILM) for this virus, which shares greater than 80 % amino acid similarity in all ORFs except X and P with the sanguinolenta strain of this species (SYDV). Protein localization …

In Vivo Localization Of Iris Yellow Spot Tospovirus (Bunyaviridae)-Encoded Proteins And Identification Of Interacting Regions Of Nucleocapsid And Movement Proteins, Diwaker Tripathi, Gaurav Raikhy, Michael M. Goodin, Ralf G. Dietzgen, Hanu R. Pappu

Plant Pathology Faculty Publications

BACKGROUND: Localization and interaction studies of viral proteins provide important information about their replication in their host plants. Tospoviruses (Family Bunyaviridae) are economically important viruses affecting numerous field and horticultural crops. Iris yellow spot virus (IYSV), one of the tospoviruses, has recently emerged as an important viral pathogen of Allium spp. in many parts of the world. We studied the in vivo localization and interaction patterns of the IYSV proteins in uninfected and infected Nicotiana benthamiana and identified the interacting partners.

PRINCIPAL FINDINGS: Bimolecular fluorescence complementation (BiFC) analysis demonstrated homotypic and heterotypic interactions between IYSV nucleocapsid …

Construction Of A Sonchus Yellow Net Virus Minireplicon: A Step Toward Reverse Genetic Analysis Of Plant Negative-Strand Rna Viruses, Uma Ganesan, Jennifer N. Bragg, Min Deng, Sharon Marr, Mi Yeon Lee, Shasha Qian, Manling Shi, Justin Kappel, Cole Peters, Yeon Lee, Michael M. Goodin, Ralf G. Dietzgen, Zhenghe Li, Andrew O. Jackson

Plant Pathology Faculty Publications

Reverse genetic analyses of negative-strand RNA (NSR) viruses have provided enormous advances in our understanding of animal viruses over the past 20 years, but technical difficulties have hampered application to plant NSR viruses. To develop a reverse genetic approach for analysis of plant NSR viruses, we have engineered Sonchus yellow net nucleorhabdovirus (SYNV) minireplicon (MR) reporter cassettes for Agrobacterium tumefaciens expression in Nicotiana benthamiana leaves. Fluorescent reporter genes substituted for the SYNV N and P protein open reading frames (ORFs) exhibited intense single-cell foci throughout regions of infiltrated leaves expressing the SYNV MR derivatives and the SYNV nucleocapsid (N), phosphoprotein …

Alternative Methods Of Control For Phytophthora Nicotianae Of Tobacco, Anna M. Holdcroft

Theses and Dissertations--Plant Pathology

Kentucky is the nation’s leading producer of burley tobacco and the crop’s most economically important disease is black shank, caused by Phytophthora nicotianae (Pn). Current management is effective, however, problems with expense and pathogen persistence are issues. Two alternative methods for control of Pn were examined: biofumigation and soil application of an organic, yeast fermentation‐derived product (Soil‐Set). Field studies in 2009 and 2010 found no effect on populations of fungi, disease severity of Pn, and yield between mustard‐ and wheat‐amended plots. Experiments in the greenhouse suggested that survival of Pn was impacted by biomass rather than biofumigation. Biofumigation is not …

The Combined Effect Of Environmental And Host Factors On The Emergence Of Viral Rna Recombinants, Hannah M. Jaag, Peter D. Nagy

Plant Pathology Faculty Publications

Viruses are masters of evolution due to high frequency mutations and genetic recombination. In spite of the significance of viral RNA recombination that promotes the emergence of drug-resistant virus strains, the role of host and environmental factors in RNA recombination is poorly understood. Here we report that the host Met22p/Hal2p bisphosphate-3'-nucleotidase regulates the frequency of viral RNA recombination and the efficiency of viral replication. Based on Tomato bushy stunt virus (TBSV) and yeast as a model host, we demonstrate that deletion of MET22 in yeast or knockdown of AHL, SAL1 and FRY1 nucleotidases/phosphatases in plants leads to increased TBSV recombination …

A Unique Role For The Host Escrt Proteins In Replication Of Tomato Bushy Stunt Virus, Daniel Barajas, Yi Jiang, Peter D. Nagy

Plant Pathology Faculty Publications

Plus-stranded RNA viruses replicate in infected cells by assembling viral replicase complexes consisting of viral- and host-coded proteins. Previous genome-wide screens with Tomato bushy stunt tombusvirus (TBSV) in a yeast model host revealed the involvement of seven ESCRT (endosomal sorting complexes required for transport) proteins in viral replication. In this paper, we show that the expression of dominant negative Vps23p, Vps24p, Snf7p, and Vps4p ESCRT factors inhibited virus replication in the plant host, suggesting that tombusviruses co-opt selected ESCRT proteins for the assembly of the viral replicase complex. We also show that TBSV p33 replication protein interacts with Vps23p ESCRT-I …

The Action Of Antibiotics And Antimetabolites On The Tobacco Mosaic Virus Infection Process In Bean Leaves, Virendra Nayyar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The action of 28 antibiotics and antimetabolites at varying concentrations was studied in coincidence with the bioassay of tobacco mosaic virus on detached bean leaves by using an ultrasonic method of inoculation developed by Lamborn, Cochran and Chidester.¹ All tested chemicals were classified, in regard to the virus infection process, as inhibitory or stimulatory and their optimal concentrations in the inoculum were determined. Of the 28 antibiotics and antimetabolites studied, eight were found to stimulate while twenty inhibited TMV infection in bean leaves. From the results of these experiments, an attempt was made to characterize the nature of the …

Tobacco Seed-Bed Management, A E. Baker

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

A SUCCESSFUL tobacco crop depends initially on an ample supply of well-grown, disease-free seedlings available early in the planting season.

If planting is held up due to a poor supply of seedlings, the resulting crop will not be grown in the most favourable part of the season. Late-grown crops nearly always give low returns.