Glabrous Brassica napus cv Westar and very hairy AtGL3+ B. napus were transformed using Agrobacterium tumefaciens and either a full length trichome regulatory gene BnTTG1 (isoform 1 coding region called O-TTG1) or an RNAi cassette with 260 bp of a conserved region between isoform I and II (called K-TTG1), each driven by the CaMV 35S promoter. Agronomic and trichome phenotypes were observed in the resulting lines. Transformed lines developed in the glabrous Westar background showed no changes in growth or trichome density and transformation efficiency was similar to that of an empty vector control construct. Over-expression of BnTTG1 in the AtGL3+ B. napus background resulted in low transformant survival and poor seed viability, with the only surviving line O-3-7 being taller than non-transformed lines and with a completely glabrous phenotype. The two knock-down lines with the lowest BnTTG1 expression showed a dramatic increase in trichome density, with longer trichomes and expanded trichome density (up to the 12th leaf in the K-5-8 line) compared to the AtGL3+ hairy background line, which showed increased trichome density only on the first three leaves. Moreover, K-5-8 plants were healthy, with both vegetative and reproductive growth similar to that of Westar non-transgenic control plants under both greenhouse and field conditions. The relative expression of five B. napus primary trichome regulatory genes and AtGL3 was measured in three different tissues of B. napus Westar, and the AtGL3+, K-5-8 and O-3-7 transgenic lines. Over-expression of AtGL3 resulted in changes in the expression of BnGL3, BnGL2 and BnTRY. Manipulation of BnTTG1 levels also resulted in changes in expression of these three genes in addition to AtGL3. AtGL3+ plants and O-3-7 also showed increased red pigment accumulation in several above ground vegetative tissues including cotyledons, hypocotyl and leaves, whereas the K-5-8 line (knock down of TTG1) had less anthocyanin in the same tissues. The level of anthocyanin accumulation corresponded to the relative expression of the three primary anthocyanin regulatory genes BnDFR, BnANS and BnGST. In a laboratory bioassay, diamondback moth (DBM) adults (Plutella xylostella) laid more eggs on hairy leaves of K-5-8 than glabrous Westar. However, more feeding damage from young DBM larvae was observed on Westar leaves than K-5-8 in both choice and no-choice feeding assays. In a field test comparing Phyllotreta flea beetle feeding, the hairy K-5-8 leaves showed between a 30-50% reduction in feeding over four ratings on 14 to 28 day old seedlings. Curiously, the glabrous cotyledons of the two hairy lines (AtGL3+ and K-5-8) proved to be more resistant than wild type B. napus Westar cotyledons from Helix XTra® insecticide-treated or non-treated seed. These data support the introduction of AtGL3 and the knockdown of BnTTG1 to induce a dense trichome phenotype, into otherwise glabrous B. napus, resulting in an increased host plant resistance to crucifer insects, without agronomic penalties.

Ctenocephalides felis is a major pest of companion animals worldwide. This project aimed to generate novel genetic resources for C. felis and develop tools to aid drug-target identification and validation. Sample handling methods were assessed and candidate reference genes validated, to ensure quality of RNA samples and reliable gene expression normalisation. Piercing C. felis samples prior to storage in RNAlater ensured RNA integrity was maintained over time. Glyceraldehyde 3-phosphate dehydrogenase , 60S ribosomal protein L19 and elongation factor-1α were demonstrated as stable reference genes across all comparisons tested. A C. felis transcriptome encompassing multiple developmental stages, sexes and tissues was sequenced and de novo assemblies produced with two assemblers, Trinity and Oases. Each assembly contained >100000 contigs. Annotation of the assemblies generated functional insight, such as top BLAST hits, GO annotations and signal peptide predictions. The Trinity assembly was deemed the highest quality and searched for genes of interest, involved in development. Expression analysis of selected transcripts across stadia gave insight into developmental processes, and demonstrated the utility of the transcriptome. This study was the first to demonstrate that C. felis can mount an RNAi response upon exposure to dsRNA. Knockdown of glutathione S-transferase σ (GSTσ), was demonstrated in adult C. felis: ≈80 % knockdown following microinjection of dsGSTσ; ≈64 % knockdown after soaking in dsGSTσ; ≈96 % knockdown after continuous feeding on dsGSTσ. RNAi machinery was identified in C. felis. siRNAi pathway components, Dicer 2 and Argonaute 2, were upregulated following dsRNA exposure. Dicer 2 was knocked-down by soaking in dsDicer2, although results of an “RNAi of RNAi” experiment were inconclusive. Transcripts encoding machinery putatively involved in dsRNA uptake and breakdown were also identified. Through these studies, this project has generated novel insights into C. felis biology and opened up new avenues for research.

Typescript Includes bibliographical references

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute, 1939. / Abstract. Includes bibliographical references (leaves 64-65). Also available via the Internet.

No description available.

This research investigated the phenology of the striped flea beetle (Phyllotreta striolata (Fabricius) (SFB) and crucifer flea beetle (Phyllotreta cruciferae (Goeze)) (CFB), and examined the efficacy and the persistence of biological activity of the reduced-risk insecticides cyantraniliprole, clothianidin, and thiamethoxam applied as seed treatments to spring canola. Yellow sticky cards were placed around field perimeters in order to assess if CFB and SFB have synchronous phenology. It was found that CFB and SFB have largely asynchronous populations in southern Ontario. In laboratory bioassays, while flea beetle control with cyantraniliprole was comparable to that provided by thiamethoxam or clothianidin at the cotyledon stage, control did not persist through the 1st and 2nd leaf stages. Thiamethoxam and clothianidin both provided moderate control of flea beetles in both 1st and 2nd leaves. Field studies suggested that cyantraniliprole may offer control of flea beetles comparable to that provided by thiamethoxam and clothianidin. / E.I. DuPont Canada Co.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Includes bibliographical references (p. 103-105).

Biocontrol has been critized because the target effects of biocontrol introductions have not been studied rigorously. The objectives of this thesis were 1)to assess quantitatively the efficacy of a classical biocontrol agent after its release and 2)to suggest factors that affect the density and distribution of the biocontrol agent. In 1997, Aphthona lacertosa, a root-feeding flea beetle that is native to Europe, was released for the biological control of leafy spurge in Alberta. The beetles had established at more than 75% of the release sites that were monitored in 1999. In 2000, the peak abundance of A.lacertosa across release sites ranged from low (<10 beetles m-2) to high (>70 beetles m-2). Sites with high beetle densities had a significantly greater local (ie. within 5m of release point) reduction of leafy spurge than sites with low beetle densities. The density and distribution of A. lacertosa are affected by cumulative degree-days (CDD) at the release site and plant lacertosa are affected by cumulative degree-days (CDD) at the release site and plant morphology, respectively. Beetle population growth may be enhanced by releasing A. lacertosa at sites where there are more CDD. It is expected that high densities of A. lacertosa will effectively control leafy spurge populations. / 93 leaves : ill. (some col.) ; 29 cm.

Thesis (Ph.D. (Zoology & Entomology)) - Rhodes University, 2009.