Recipient Organization
WINSTON-SALEM STATE UNIVERSITY
601 MARTIN LUTHER KING JR. DRIVE
WINSTON-SALEM,NC 27110
Performing Department
(N/A)
Non Technical Summary
The nucleus and the plastid are compartments in plant cells that contain DNA. Each compartment makes an important contribution to the growth and development of the whole plant. Plastid development and function depend on cooperation between two genetic compartments because genes in both the nucleus and the chloroplast produce proteins for chloroplast structure and function. Thus, the genes in the nucleus and the plastid have coevolved and adapted to produce a relationship that coordinates nuclear and plastid gene expression. In plants of the genus Oenothera, commonly known as the evening primrose, production of hybrids among member of the genus creates novel combinations of plastid and nuclear types. In some of the hybrids the cooperative relationship between the plastid and the nucleus is disrupted and leaves exhibit symptoms of abnormal chloroplast function which are most likely due to an incompatible interaction between the nucleus and the plastid. The objectives of
this project include a physiological characterization of chloroplasts in plants with compatible and incompatible nucleus-plastid combinations and an evaluation of levels of plastid gene expression. The primary goal is to elucidate the mechanisms involved in the expression of incompatibility. This project will enhance the understanding of the processes involved in the communication between the nucleus and the chloroplast, processes that ultimately determine the efficiency of chloroplast function and the ability of a plant to increase productivity.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
Characterize the in vivo photosynthetic activity of the plants with incompatible genome-plastome combinations. Determine whether there is a correlation between in vivo photosynthetic activity and the expression of genome-plastome incompatibility. Compare levels of chloroplast mRNA in plants with compatible and incompatible genome-plastome combinations to determine whether there is a correlation between photosynthetic activity, genome-plastome compatibility and chloroplast gene expression. Identify genes or proteins that are part of the communication pathway between the nucleus and the chloroplast. Enhance the understanding of the processes involved in the communication between the nucleus and the chloroplast, processes that ultimately determine the efficiency of the chloroplast and a plant's potential to increase productivity. Involve undergraduate students in basic research toward the goal of attracting more students toward higher education and careers in plant
biology or agriculture.
Project Methods
In vivo photosynthetic rates will be measured to determine rates of light-induced CO2 uptake, the quantum yield of photosynthesis, transpiration rates and water use efficiency in the leaves of plants with compatible and incompatible genome-plastome combinations. An estimate of the relative number of light-harvesting chlorophyll proteins in photosynthetic membranes can be obtained from the kinetics of the rate of photosynthesis versus light intensity. If there is a quantitative difference in the quantity of the chlorophyll proteins in plants with compatible and incompatible genome-plastome combinations, then there should be a difference in the light-saturation curves for photosynthesis and in the relative abundance of chlorophyll protein levels. Chloroplast membrane proteins from plants with compatible and incompatible genome-plastome combinations will be isolated, fractionated by electrophoresis, blotted (Western blot) and probed with antisera raised against
polypeptides of the chlorophyll protein complexes. Quantitative differences in the levels of chlorophyll binding polypeptides would support the hypothesis that plants with incompatible genome-plastome combinations have altered levels of chlorophyll proteins. The levels of chloroplast gene expression will be determined by examining levels of mRNA over the course of development. RNA isolated from plants with bleached, variegated and fully green leaves will be analyzed by hybridization of Northern blots with chloroplast DNA probes. Any observed differences in mRNA levels will identify the chloroplast genes whose level of expression is affected when a plastome is combined with an incompatible nuclear genome. To detect very small differences in RNA levels, a quantitative PCR assay will be developed to compare levels of gene expression in plants with compatible and incompatible genome-plastome combinations.