Biology subjects

Weraduwage, S. M.

Publications and source records attributed to Weraduwage, S. M..

3 recordsLinked to original sources

bioRxiv2024

The effect of constitutive root isoprene emission on root phenotype and physiology under control and salt stress conditions

ABSTRACTIsoprene, a volatile hydrocarbon, is typically emitted from the leaves and other aboveground plant organs; isoprene emission from roots is not well studied. Given its well-known function in plant growth and defense aboveground, isoprene may also be involved in shaping root physiology to resist belowground stress. We used isoprene-emitting transgenic lines (IE) and a non-emitting empty vector and/or wild type lines (NE) of Arabidopsis to elucidate the roles of isoprene in root physiology and salt stress resistance. We assessed root phenotype and metabolic changes, hormone biosynthesis and signaling, and stress-responses under normal and saline conditions of IE and NE lines. We also analyzed the root transcriptome in the presence or absence of salt stress. IE lines emitted isoprene from roots, which was associated with higher primary root growth, root biomass, and root/shoot biomass ratio under both control and salt stress conditions. Transcriptome data indicated that isoprene altered the expression of key genes involved in hormone metabolism and plant responses to stress factors. Our findings reveal that root constitutive isoprene emission sustains root growth also under salinity by regulating and/or priming hormone biosynthesis and signaling mechanisms, amino acids biosynthesis, and expression of key genes relevant to salt stress defense.

plant biology↗

bioRxiv2018

Prospects for enhancing leaf photosynthetic capacity by manipulating mesophyll cell morphology

Leaves are beautifully specialized organs designed to maximize the use of light and CO2 for photosynthesis. Engineering leaf anatomy therefore brings great potential to enhance photosynthetic capacity. Here we review the effect of the dominant leaf anatomical traits on leaf photosynthesis and confirm that a high chloroplast surface area exposed to intercellular airspace per unit leaf area (Sc) is critical for efficient photosynthesis. The possibility of improving Sc through appropriately increasing mesophyll cell density is further analyzed. The potential influences of modifying mesophyll cell morphology on CO2 diffusion, light distribution within the leaf, and other physiological processes are also discussed. Some potential target genes regulating leaf mesophyll cell proliferation and expansion are explored. Indeed, more comprehensive research is needed to understand how manipulating mesophyll cell morphology through editing the potential target genes impact leaf photosynthetic capacity and related physiological processes. This will pinpoint the targets for engineering leaf anatomy to maximize photosynthetic capacity.\n\nHighlightCell morphology in leaves affects photosynthesis by controlling CO2 diffusion and light distribution. Recent work has uncovered genes that control cell size, shape, and number paving the way improved photosynthesis.

plant biology↗

bioRxiv2018

Loss of Peroxisomal Hydroxypyruvate Reductase Inhibits Triose Phosphate Isomerase but Stimulates Cyclic Photosynthetic Electron Flow and the Glc-6P-Phosphate Shunt

The oxygenation of ribulose 1,5-bisphosphate by Rubisco is the first step in photorespiration and reduces the efficiency of photosynthesis in C3 plants. Our recent data indicates that mutants in photorespiration have increased rates of photosynthetic cyclic electron flow around photosystem I. We investigated mutant lines lacking peroxisomal hydroxypyruvate reductase to determine if there are connections between 2-PG accumulation and cyclic electron flow. We found that 2-PG is a competitive inhibitor of triose phosphate isomerase (TPI), an enzyme in the Calvin-Benson cycle that converts glyceraldehyde 3-phosphate to dihydroxyacetone phosphate. This block in metabolism could be overcome if glyceraldehyde 3-phosphate is exported to the cytosol where the cytosolic triose phosphate isomerase could convert it to dihydroxyacetone phosphate. We found evidence that carbon is reimported as Glc-6P-phosphate forming a cytosolic bypass around the block of stromal TPI. However, this also stimulates a Glc-6P-phosphate shunt, which consumes ATP, which can be compensated by higher rates of cyclic electron flow.\n\nOnce Sentence SummaryTriose phosphate isomerase is inhibited in plants lacking hydroxypyruvate reductase 1 and this is overcome by exporting triose phosphate to the cytosol and importing Glc-6P, which stimulates a Glc-6P-phosphate shunt and cyclic electron flow.

plant biology↗