1a. Objectives (from AD-416):
The long term goal is to develop knowledge and biotechnology strategies that can be used for effective manipulation of tree architecture traits and produce superior tree forms that improve productivity, reduce management costs, and more efficiently utilize natural resources. Here, we propose to: 1) identify causative genetic differences responsible for five single locus architecture traits in peach (pillar, compact, forked, weeping, and brachytic dwarf) and 2) perform preliminary physiological and molecular characterization of the underlying genes.
1b. Approach (from AD-416):
This work will be accomplished using a new strategy pioneered by the PDs that enables rapid identification of a single or small number of candidate genes responsible for single locus traits in peach. Briefly, it involves sequencing pooled genomes from segregating populations using next generation sequencing technologies. The resulting data will be mined for polymorphisms, and allele frequencies from individual genome pools will be calculated. Finally, the frequencies are graphed by chromosome position to simultaneously reveal the physical location of the trait and the causative polymorphism. Identified candidate genes will be confirmed via molecular markers designed from the genome sequences and functional tested by transformation into plum.
3. Progress Report:
The successes of the ‘Green Revolution’ in cereal crops (1940-1970) were largely attributed to improvements in plant architecture that enabled high yields and higher planting densities. Similar efforts in other plant species have not come to fruition and there exists tremendous opportunity to make significant productivity improvements in numerous other crops, particularly tree species which occupy large land areas, are labor intensive, and require the use of large amounts of chemicals. The objectives of this project were designed to fill knowledge gaps in our understanding of tree growth and development to enable tree architectural improvements through breeding and biotechnology. The project leverages existing mutations of peach trees that show distinct growth forms that are common in numerous trees species. These include dwarf, weeping, compact, and pillar/columnar types. The primary goal is to identify the genes responsible for these key traits. Over the past year, the project has led to the identification of genes that control the growth direction (up or down) of branches in trees and other plants. In addition, a gene that controls overall tree size was also identified. The ability to manipulate these genes will enable the development of trees and plants with shapes better suited for large scale farming which will ultimately increase fruit production, decrease pesticide use, and result in cheaper prices for fresh and processed produce. The work also has significant implications for plant biology and furthers our general understanding of plant development and evolution.