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Resistance To Aflatoxin Accumulation In Maize Mediated By Host-Induced Gene Silencing Of Aspergillus Flavus Alkaline Protease And O-Methyltransferase-A Genes, Olanike Omotola Omolehin
Resistance To Aflatoxin Accumulation In Maize Mediated By Host-Induced Gene Silencing Of Aspergillus Flavus Alkaline Protease And O-Methyltransferase-A Genes, Olanike Omotola Omolehin
LSU Doctoral Dissertations
Aspergillus flavus is a soil-borne fungal pathogen that infects maize and produces aflatoxins. In the current study, portions of the alkaline protease (alk) and the O-methyl transferase (omtA) genes, which are key in A. flavus virulence and aflatoxin biosynthesis, respectively, were targeted for suppression through an RNAi (RNA interference) approach known as Host-Induced Gene Silencing (HIGS). Separate RNAi vectors were designed to carry regions of the alk and omtA gene fragments (Alk-RNAi and OmtA-RNAi) and introduced into B104 maize zygotic embryos. Eight and six transformation events were positive for the alk and omtA transgene, respectively. …
Sensitivity And Resistance Of Cercospora Kikuchii, Causal Agent Of Cercospora Leaf Blight And Purple Seed Stain Of Soybean, To Selected Fungicides, Paul Patrick Price, Iii
Sensitivity And Resistance Of Cercospora Kikuchii, Causal Agent Of Cercospora Leaf Blight And Purple Seed Stain Of Soybean, To Selected Fungicides, Paul Patrick Price, Iii
LSU Doctoral Dissertations
ABSTRACT Isolates of Cercospora kikuchii, the causal agent of Cercospora leaf blight (CLB) and purple seed stain (PSS), were used to determine baseline sensitivities to selected quinone outside inhibitor (QoI) and demethylation inhibitor (DMI) fungicides by conducting radial growth assays on fungicide-amended media. The effective concentration to inhibit 50% radial growth (EC50) for each isolate was calculated by linear interpolation of the dose-response relationship. All baseline distributions were non-normal with outliers towards the less sensitive ends of the spectra, and median EC50 values for azoxystrobin, pyraclostrobin, trifloxystrobin, flutriafol, propiconazole, and tetraconazole were 0.081, 0.013, 0.012, 0.273, 0.143, 1.47 µg/ml, respectively. …
Comparative Proteome And Qpcr Analysis Of The Sugarcane Reaction To Leaf Scald Caused By Xanthomonas Albilineans, Freddy Fernando Garces-Obando
Comparative Proteome And Qpcr Analysis Of The Sugarcane Reaction To Leaf Scald Caused By Xanthomonas Albilineans, Freddy Fernando Garces-Obando
LSU Doctoral Dissertations
Leaf scald is an important disease of sugarcane caused by Xanthomonas albilineans (Xa). Leaf scald is controlled by the development and planting of resistant cultivars. However, erratic symptom expression makes conventional screening for resistance difficult. In addition, the mechanisms of resistance to leaf scald are not completely understood. Real-time, quantitative polymerase-chain-reaction (qPCR) assays were developed utilizing SYBR Green for a highly sensitive detection method or a TaqMan probe to quantify Xa populations in infected plants. Xa populations detected by qPCR followed similar trends to disease severity ratings and vascular infection results for two resistant and two susceptible cultivars under greenhouse …
Cercospora Leaf Blight Of Soybean: Pathogen Vegetative Compatibility Groups, Population Structure, And Host Resistance, Guohong Cai
LSU Doctoral Dissertations
Nitrogen nonutilizing mutants were used to assess vegetative compatibility of 58 isolates of Cercospora kikuchii, 55 of which were isolated from soybean plants in Louisiana. Only 16 of 56 self-compatible isolates were assigned to six multi-member vegetative compatibility groups (VCGs), 01-06, with two or three isolates in each VCG. The other 40 isolates were not vegetatively compatible with any isolates other than themselves. All six multi-member VCGs contained isolates from different soybean cultivars, and three included isolates from different locations. Only one VCG included isolates both from soybean leaves and from seeds, while two and three multi-member VCGs included isolates …