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Full-Text Articles in Life Sciences

Occurrence Of Putative Endornaviruses In Non-Cultivated Plant Species And Characterization Of A Novel Endornavirus In Geranium Carolinianum, Rachel Herschlag Nov 2017

Occurrence Of Putative Endornaviruses In Non-Cultivated Plant Species And Characterization Of A Novel Endornavirus In Geranium Carolinianum, Rachel Herschlag

LSU Master's Theses

Endornaviruses are RNA viruses, which can infect plants yet cause no apparent symptoms. To date, most descriptions of endornaviruses infecting plants have been in cultivated species. A survey for endornaviruses in non-cultivated plants was initiated in 2015 and continued through 2017 in Baton Rouge, Louisiana. Two hundred and seven plant species were tested for distinctive dsRNA profiles by selective extraction and gel electrophoresis, of which seven contained endornavirus-like dsRNA. RT-PCR amplification of an endornavirus-specific sequence supported the endornavirus nature of six of the seven samples. Of the six host species, one species, Geranium carolinianum was confirmed as being infected with …


Distinguishing Isolates Of Rotylenchulus Reniformis Endemic In Louisiana On The Basis Of Root-Associated Females And Egg Masses, Benjamin Mcinnes Nov 2017

Distinguishing Isolates Of Rotylenchulus Reniformis Endemic In Louisiana On The Basis Of Root-Associated Females And Egg Masses, Benjamin Mcinnes

LSU Master's Theses

The reniform nematode Rotylenchulus reniformis is a major pathogen of soybean and cotton in Louisiana. Previous studies have shown that populations of reniform nematode throughout the southern United States vary in reproduction and pathogenicity. Limited studies have been conducted to evaluate the reproduction and pathogenicity of populations of R. reniformis endemic in Louisiana. Studies with isolates of the nematode from eight cotton-producing parishes focused solely on reproduction of the root-associated infective and swollen female life stages with and without attached egg masses on the cotton genotypes MT2468 Ren3, M713 Ren5, and Stoneville 4946GLB2 and the soybean genotypes PI 548316, PI …


Characterization Of Aspergillus Flavus Soil And Corn Kernel Populations From Eight Mississippi River States, Jorge A. Reyes Pineda Nov 2017

Characterization Of Aspergillus Flavus Soil And Corn Kernel Populations From Eight Mississippi River States, Jorge A. Reyes Pineda

LSU Master's Theses

Aspergillus flavus is a saprophytic ascomycete that can also actively invade the seed of crops and potentially contaminate them with harmful aflatoxins. Management of A. flavus currently relies mostly on biocontrol. However, there is still a lot to learn about its biology and ecology so the current approach can be improved. An A. flavus population survey was undertaken during the fall of 2014 across eight Mississippi River states to determine population diversity and geographic distribution of VCGs. Isolates from corn and soil were also characterized for VCG, sclerotial morphotype, mating type, cyclopiazonic acid, and aflatoxin production in order to determine …


Sweetpotato Virus C And Its Contribution To The Potyvirus Complex In Sweetpotato (Ipomoea Batatas), Favio E. Herrera Eguez Nov 2017

Sweetpotato Virus C And Its Contribution To The Potyvirus Complex In Sweetpotato (Ipomoea Batatas), Favio E. Herrera Eguez

LSU Doctoral Dissertations

In Louisiana, sweetpotato (Ipomoea batatas) is infected in Louisiana by the four ubiquitous potyviruses: Sweetpotato feathery mottle virus (SPFMV), Sweetpotato virus G (SPVG), Sweetpotato virus 2 (SPV2) and the strain of SPFMV previously known as the common strain, recently renamed as Sweetpotato virus C (SPVC). These four viruses belong to the Potyviridae family, with single stranded RNA of ~11kb. In this group of plant viruses, a single polyprotein is coded entirely but later cleaved into ten mature proteins: P1, HC-pro, P3, 6K1, CI, 6K2, NIa-VPg, NIa-Pro Nib and Coat Protein (CP). In sweetpotato potyviruses, two additional open reading …


Incidence Of Aphelenchoides Besseyi In Rice In Louisiana And Host Status Of The Most Widely Planted Cultivars, Felipe Mendes Carvalho Godoy Nov 2017

Incidence Of Aphelenchoides Besseyi In Rice In Louisiana And Host Status Of The Most Widely Planted Cultivars, Felipe Mendes Carvalho Godoy

LSU Master's Theses

Aphelenchoides besseyi, the causal agent of white tip disease of rice, has been considered a minor pest of rice during the past 50 years in the United States. Recently this nematode has been found in a number of quarantine samples in Louisiana and Arkansas. Objectives of this research were to determine incidence of this nematode in commercial seed sold to producers in Louisiana and to determine the host status of major cultivars currently produced in the state. During 2015-2016, a total of 216 seed samples representing 3 medium grain, 18 long grain, and 4 long grain hybrid cultivars were …


Virulence Phenotypes Of Rotylenchulus Reniformis: Evaluation Of Host Status Of Cotton And Utility Of Single Nucleotide Polymorphisms (Snps) For Identification, Churamani Khanal Nov 2017

Virulence Phenotypes Of Rotylenchulus Reniformis: Evaluation Of Host Status Of Cotton And Utility Of Single Nucleotide Polymorphisms (Snps) For Identification, Churamani Khanal

LSU Doctoral Dissertations

Comparative reproduction and pathogenicity of reniform nematode (Rotylenchulus reniformis) populations derived from single-egg masses and collected form West Carroll (WC), Rapides (RAP), Morehouse (MOR), and Tensas (TEN) parishes in Louisiana were evaluated in microplot and greenhouse trials. Data from microplot trials showed significant differences among isolates of reniform nematode in both reproduction and pathogenicity on upland cotton (Gossypium hirsutum) cultivars Phytogen 499 WRF, Deltapine 1133 B2RF, and Phytogen 333 WRF. Across all cotton cultivars, MOR and RAP isolates had the greatest and the least reproduction values of 331.8 and 230.2, respectively. Reduction in plant dry weight, …


Pathogenicity And Reproduction Of Isolates Of Reniform Nematode, Rotylenchulus Reniformis, From Louisiana On Soybean And Utility Of Single Nucleotide Polymorphisms To Evaluate Genetic Variability, Herath Mudiyanselage Kularathna Nov 2017

Pathogenicity And Reproduction Of Isolates Of Reniform Nematode, Rotylenchulus Reniformis, From Louisiana On Soybean And Utility Of Single Nucleotide Polymorphisms To Evaluate Genetic Variability, Herath Mudiyanselage Kularathna

LSU Doctoral Dissertations

Experiments were conducted to evaluate soybean, Glycine max (L.) Merr., responses to indigenous isolates of the reniform nematode (Rotylenchulus reniformis) in Louisiana and to understand the genetic variability of these native isolates. Microplot and greenhouse experiments were conducted to evaluate the comparative reproduction and pathogenicity of single egg-mass populations of R. reniformis isolated from West Carroll (WC), Rapides, Tensas and Morehouse (MOR) parishes of Louisiana. Data from full-season microplot trials, displayed significant differences in reproduction and pathogenicity of the nematode with the commercial soybean cultivars REV 56R63, Pioneer P54T94R, and Dyna-Gro 39RY57. Significantly low population density was observed …


A Comparison Of Soils And Their Associated Microbial Communities As Affected By Sugarcane Cultivation, Adam Francis Bigott Aug 2017

A Comparison Of Soils And Their Associated Microbial Communities As Affected By Sugarcane Cultivation, Adam Francis Bigott

LSU Master's Theses

In Louisiana, sugarcane has been grown in the same soils for over 200 years. A phenomenon wherein soils with a long-term sugarcane cropping history produce decreased yields compared to adjacent land without a recent history of sugarcane cultivation has been documented in multiple sugarcane growing regions. Research in both Louisiana and internationally has shown positive plant growth responses when soils with a long-term cultivation history are sterilized or treated with selective biocides, suggesting there is a biological component to the underlying soil health issue. In this study, soil microbial ecology was compared for paired sites with short and long-term sugarcane …