DSpace Collection:
https://hdl.handle.net/2440/84544
2024-03-28T20:00:59ZHeterologous Expression and Functional Analysis of Plantago GT61 and DUF579 Genes in Arabidopsis thaliana
https://hdl.handle.net/2440/121634
Title: Heterologous Expression and Functional Analysis of Plantago GT61 and DUF579 Genes in Arabidopsis thaliana
Author: Herliana, Lina
Abstract: Mucilage released from Plantago ovata seed (psyllium) has been used for maintaining human health as a dietary fibre supplement. Heteroxylan is the main component, and its substitution affects solubility and viscosity of the end product. However, little is known about genes involved in xylan substitution so phylogenetic and transcript information were used to identify candidate genes in the GT61 and DUF579 families and their functions were tested in the model plant Arabidopsis thaliana. Plantago GT61_7, driven by a seed-coat promoter (ProDP1) was transformed into Arabidopsis using a floral dip and spray method. Ruthenium red staining of wild-type and T2 seeds from multiple independent transgenic lines showed a significant difference in the thickness of the adherent mucilage layer. The difference in mucilage phenotype suggests that GT61_7 may have a role in xylan substitution that affects seed coat adherence. This preliminary result needs to be examined using immunolabeling and monosaccharide analysis. For the DUF579 gene AT1G71690, a genome editing approach was adopted. Three single guide RNAs were designed using online tools and in silico analysis was performed to predict any changes in coding and protein sequences by each guide RNA. To test them in vitro, the CRISPR/Cas9 constructs were successfully delivered to protoplast cells using the Transient Expression in Arabidopsis Mesophyll Protoplast (TEAMP) method. However, an analysis using Tracking of Indels by Decomposition(TIDE) showed no evidence of edits in the DUF569 genomic DNA extracted from the protoplasts. Increasing the transfection efficiency or redesigning the sgRNA could lead to improved CRISPR/Cas9 activity.2017-01-01T00:00:00ZTemporal gene expression analysis reveals a synergistic effect of combined drought and heat stress in grapevine (Vitis vinifera L.)
https://hdl.handle.net/2440/114125
Title: Temporal gene expression analysis reveals a synergistic effect of combined drought and heat stress in grapevine (Vitis vinifera L.)
Author: Hu, Yikang
Abstract: Grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) is widely used for winemaking all over the world. Drought and heat stresses are two of the major abiotic stresses reducing grape quality and yield. However, drought and heat tolerance are still poorly characterized in perennial crops such as grapevine. During this study, stomatal conductance, stem water potential and leaf temperature were measured to determine plant physiological status. RNA-seq technology was used for the analysis of differentially expressed genes (DEGs) of leaf samples between the control and three treatments, which were drought, heat and a combined treatment. Gene expression profiles were grouped by treatments and timepoints. The great majority of unique DEGs were found to be induced by the combined drought and heat treatment. 169 up-regulated genes were induced by drought, 85 by heat and 1218 by the combined treatment; 78 down-regulated genes were induced by drought, 72 by heat and 1427 by the combined treatment. Three potential and significant regulation pathways of stress response were identified based on Gene Ontology (GO) analysis i.e. cytokinin-activated signalling pathway, ion transport pathway and Nitric Oxide-mediated pathway. This study provides preliminary insights into the transcriptomic response to drought and heat stress in grapevine.2017-01-01T00:00:00ZImpact of Roundup and Clearfield herbicides on soil nutrients, and the biomass, activity and diversity of soil microorganisms
https://hdl.handle.net/2440/114124
Title: Impact of Roundup and Clearfield herbicides on soil nutrients, and the biomass, activity and diversity of soil microorganisms
Author: Jiang, Jian
Abstract: Roundup and Clearfield are herbicides that have been widely used globally and their use is expected to increase in the coming years. However, these herbicides may affect soil microbes that are important for soil health because of their roles in cycling carbon and soil nutrients. There have been no studies to explore the effect of Clearfield on microorganisms. In this study, the effect of Roundup and Clearfield GM resistant herbicides on microorganisms was investigated. The experiments were designed to measure soil nutrients (available phosphorus and nitrogen), microbial biomass carbon (MBC), and microbial activity (respiration and enzymes) in the soil every 7 days over a 28 day period. Soil microbial diversity was also measured at 28 days using an amplicon sequencing based approach. The results revealed no positive or negative effects of either herbicide at their recommended and five times recommended rates. This study was conducted on soil samples in the lab, but a larger scale studies on the agronomic effects of the two herbicides on microbes in field environments are recommended.
Description: Front matter only available electronically. The complete thesis in print form is available from the University of Adelaide Library.2016-01-01T00:00:00ZImpact of in vitro induced epigenetic variation on the nutritional value of three Ghanaian sweet potato genotypes: implications on biofortification
https://hdl.handle.net/2440/114123
Title: Impact of in vitro induced epigenetic variation on the nutritional value of three Ghanaian sweet potato genotypes: implications on biofortification
Author: Akomeah, Belinda
Abstract: Biofortification aims to increase crop nutritional value to combat nutrient deficiency. Due to the prevalence of viruses, healthy cultivars of biofortified genotypes are produced through micropropagation techniques. However, during micropropagation, plants are exposed to conditions that could induce somaclonal variation, and result in phenotypic changes affecting the crop’s nutritional value. Currently, sweet potato (Ipomoea batata) is biofortified for enhanced beta-carotene content to alleviate Vitamin A Deficiency (VAD). Undesired somaclonal abnormalities acquired during in vitro culture could alter key nutrients such as beta-carotene, protein, or zinc. Therefore, it is important to ensure the clonal fidelity of the micropropagated biofortified lines. This study assessed the extent of in vitro induced epigenetic variation in the genome of meristem-cultured plants, and its correlation with the nutritional composition in three Ghanaian sweet potato genotypes (Bohye, Ogyefo and Otoo). Micropropagated plants presented no observable leaf and storage root abnormalities, but relatively lower levels of iron, protein, zinc, and glucose. Methylation Sensitive Amplification Polymorphism analysis showed a high level of in vitro induced molecular variation in micropropagated plants. Ogyefo showed the least viral incidence and epigenetic differentiation but the most profound nutritional changes, while Bohye showed the highest epigenetic variability. Further analysis indicated that epigenetic, rather than genetic, accounts for most of the observed variability. Taken collectively, this study offers an insight into the impact of micropropagation in methylation profiles, and its correlation to root quality in the improved sweet potato genotypes. The implications of these results to the ongoing bio-fortification projects are also discussed.
Description: Front matter only available electronically. The complete thesis in print form is available from the University of Adelaide Library.2016-01-01T00:00:00Z