Biology subjects

Bryan, G.

Publications and source records attributed to Bryan, G..

3 recordsLinked to original sources

bioRxiv2021

Transcriptomic Insights into the Responses in Leaves Storing Lipid Organelles under Different Irradiances

To increase the nutritional value of forage, transgenic ryegrass known as High Metabolizable Energy (HME) were previously generated that co-express cysteine-oleosin and diacylglycerol O-acyltransferase. HME not only accumulate lipids in the leaf but also has elevated CO2 assimilation and increased biomass. Shading is one of the most influencing factors for ryegrass growth environments particularly in swards. The aim of this study, therefore, was to determine the influence of irradiance levels on photosynthesis and gene expression in the HME leaves when compared with their corresponding non-transformant (NT). Under low light (150-250 {micro}mol m-2 s-1) and standard light (600-1000 {micro}mol m-2 s-1), the HME accumulated more lipid than NT. The previously reported elevated photosynthesis and increased biomass was observed when the HME were grown under standard light but not under low light. Under both light conditions, compared to NT, the HME had upregulated a number of transcripts involved in lipid metabolism, light capturing, photosynthesis, and sugar signalling network while downregulated genes participated in sugar and fructan biosynthesis. We further discuss how the HME differentially manipulated several genes other metabolic pathways including maintenance of redox homeostasis. Combined, the data suggests that the increased photosynthesis capacity in the HME likely corresponds to an increase of micro-lipid sink strength; these are influenced by available light energy and may be related to diffusional and biochemical activities of stomata. Overall, this work provides a clearly understanding of the changes in molecular and biochemical mechanisms underlying the carbon storing as leaf lipid sink of the HME ryegrass. One sentence summaryShading led to increase leaf lipid accumulation but limit the greater photosynthesis trait of high lipid ryegrass which may be related to limitation of biochemical activities of stomata.

molecular biology↗

bioRxiv2017

Mapping Loci that Control Tuber and Foliar Symptoms Caused by PVY in Autotetraploid Potato (Solanum tuberosum L.)

Potato tuber necrotic ringspot disease (PTNRD) is a tuber deformity associated with infection by the tuber necrotic strain of Potato virus Y (PVYNTN). PTNRD negatively impacts tuber quality and marketability and poses a serious threat to seed and commercial potato production worldwide. PVYNTN symptoms differ in the cultivars Waneta and Pike: Waneta expresses severe PTNRD and foliar mosaic with vein and leaf necrosis, whereas Pike does not express PTNRD and mosaic is the only foliar symptom. To map loci that influence tuber and foliar symptoms, 236 F1 progeny of a cross between Waneta and Pike were inoculated with PVYNTN isolate NY090029 and genotyped using 12,808 Potato SNPs. Foliar symptom type and severity were monitored for 10 weeks, while tubers were evaluated for PTNRD expression at harvest and again after 60 days in storage. Pairwise correlation analyses indicate a strong association between PTNRD and vein necrosis ({tau} = 0.4195). QTL analyses revealed major-effect QTLs on chromosomes 4 and 5 for mosaic, 4 for PTNRD, and 5 for foliar-necrosis symptoms. Locating QTLs associated with PVY-related symptoms provides a foundation for breeders to develop markers that can be used to screen out potato clones with undesirable phenotypes, e.g., those likely to develop PTNRD or to be symptomless carriers of PVY.

genetics↗

bioRxiv2016

DMAP - Graphical representation of physical and genetic map correlation

Next-generation sequencing approaches coupled with appropriate assembly software can provide draft genome sequences of complex organisms as a series of unordered contigs in a timely and cost effective manner. Likewise, high throughput mapping technologies such as DArT and SNP platforms can provide a high density of sequence-anchored markers with which high resolution genetic maps can be constructed. Visualising and interpreting these data requires a new generation of tools as the volume of data leads to considerable redundancy and information overload in graphical representation. DMAP provides a highly configurable visual representation of physical and genetic map correlation, reducing data representation to an aesthetically acceptable degree. It also calculates an optimal orientation for the ordered sequence contigs, highlighting markers that are anomalous and contigs which may be in erroneous positions. Output is as PDF, allowing subsequent refinement prior to print publication and vector based representation for online supplementary figures. The perl scripts have few dependencies and code is freely available under a creative commons license (CC-BY) from the authors GitHub repository at http://github.com/davidmam/DMAP.git.

bioinformatics↗