GENETICS, GENOMICS, AND MOLECULAR BIOLOGY OF ROSACEOUS FRUIT TREES
Current Research
I am delighted to announce that I have recently accepted a Research Geneticist position at the USDA-ARS Tree Fruit Research Lab in Wenatchee, WA. In this new position, I will be using genetics and genomics to address key issues in pears, focusing a large part of my research on pear rootstocks. I am interested in applying genetic tools to better understand dwarfing and precocity, graft compatibility and function, developing tools to enhance breeding efforts, as well as other topics related to architecture and physiology. I am very excited to apply my background and skills to this pear genetics position to support the pear industry. Feel free to check back soon to hear more about how I am building the research questions in my lab!
Past Research
As a post-doc in the Kalcsits lab at WSU Tree Fruit Research and Extension Center, I investigated the molecular and physiological mechanisms underlying acclimation to heat and light in apple fruit.
How do apple fruit acclimate to heat and light stress?
Sunburn is a physiological skin disorder caused by excess heat and light, which leads to the development of bleached, brown, or necrotic spots on the surface of the apple. Sunburn is responsible for up to 10% loss in Washington State’s apple production. The high heat and light conditions that induce sunburn are expected to become more common in the coming years with the advancement of climate change. My research focused on the ability and underlying mechanisms of apples to acclimate to the heat- and light-stress conditions that cause sunburn. Using this information, we hope to inform horticultural practices that will allow for improved acclimation to these stressors and improved crop production.
How do apple fruit acclimate to heat and light stress?
Sunburn is a physiological skin disorder caused by excess heat and light, which leads to the development of bleached, brown, or necrotic spots on the surface of the apple. Sunburn is responsible for up to 10% loss in Washington State’s apple production. The high heat and light conditions that induce sunburn are expected to become more common in the coming years with the advancement of climate change. My research focused on the ability and underlying mechanisms of apples to acclimate to the heat- and light-stress conditions that cause sunburn. Using this information, we hope to inform horticultural practices that will allow for improved acclimation to these stressors and improved crop production.
As a Research Molecular Biologist at the USDA-ARS Appalachian Fruit Research Station in Kearneysville, WV, my research focused on understanding the genetic and environmental signals that shape plant architecture, for which I received a Postdoctoral Fellowship from AFRI NIFA.
The role of DRO genes in root architecture
Root system architecture (RSA) is the spatial distribution of roots within the soil, which is determined by factors such as root length, growth rate, branching rate, and growth orientation, or angle. RSA influences plant productivity by impacting uptake of water and nutrients, interaction with soil microbes, and soil anchorage. Therefore, these factors are important for breeding and engineering rootstocks in agriculture. DEEPER ROOTING 1 (DRO1), a gene that was originally identified in rice, affects root orientation and overall root system depth. Using genetic and molecular tools, I investigated the function of DRO1 and related genes in the roots of tree crops and Arabidopsis. With this information, I worked toward developing tools for rootstock breeding and engineering for improved performance under water-stressed conditions.
The role of DRO genes in root architecture
Root system architecture (RSA) is the spatial distribution of roots within the soil, which is determined by factors such as root length, growth rate, branching rate, and growth orientation, or angle. RSA influences plant productivity by impacting uptake of water and nutrients, interaction with soil microbes, and soil anchorage. Therefore, these factors are important for breeding and engineering rootstocks in agriculture. DEEPER ROOTING 1 (DRO1), a gene that was originally identified in rice, affects root orientation and overall root system depth. Using genetic and molecular tools, I investigated the function of DRO1 and related genes in the roots of tree crops and Arabidopsis. With this information, I worked toward developing tools for rootstock breeding and engineering for improved performance under water-stressed conditions.
TAC1 and LAZY1 in shoot architecture
Shoot architecture similarly influences many aspects of a plant’s interaction with the environment. Two genes, TAC1 and LAZY1, control the angle of branches, leaves, and tillers across plant species. Together with DRO1, these genes belong to the IGT gene family, which can be found in all land plants. In addition to understanding the functions and interactions between these genes, I researched how branch angle and TAC1 and LAZY1 function are influenced by environmental signals such as light and gravity.
Graduate Research
My Ph.D. research in the Dr. Jennifer Nemhauser’s lab at the University of Washington focused on protein degradation dynamics within a plant hormone signaling pathway, and their role in plant developmental processes, for which I received a NIH Developmental Biology Training Grant.
Auxin-induced degradation dynamic and plant development
Development requires cells to send and receive information, often in the form of small molecules or peptides. Information can be encoded in the dynamics of signaling (i.e. rates or frequencies of signals), not just in the relative abundance of signaling molecules. In plants, response to the hormone auxin is a useful tool for studying the role that signal dynamics play in development. Auxin transmits signals through a signaling pathway consisting of a set of protein components. Each component in the auxin signaling pathway belongs to a protein family, and different family members play distinct roles throughout development. In collaboration with the Klavins lab, I worked as part of an interdisciplinary team taking a synthetic biology approach to characterize plant protein properties and test hypotheses about auxin signaling dynamics by porting the pathway into yeast. Building on findings from the yeast system, I designed a library of repressor proteins with varying degradation rates, which I tested using a novel plant-based protein degradation assay, and used these to demonstrate the importance of their dynamics in plant development, particularly in root development.
Auxin-induced degradation dynamic and plant development
Development requires cells to send and receive information, often in the form of small molecules or peptides. Information can be encoded in the dynamics of signaling (i.e. rates or frequencies of signals), not just in the relative abundance of signaling molecules. In plants, response to the hormone auxin is a useful tool for studying the role that signal dynamics play in development. Auxin transmits signals through a signaling pathway consisting of a set of protein components. Each component in the auxin signaling pathway belongs to a protein family, and different family members play distinct roles throughout development. In collaboration with the Klavins lab, I worked as part of an interdisciplinary team taking a synthetic biology approach to characterize plant protein properties and test hypotheses about auxin signaling dynamics by porting the pathway into yeast. Building on findings from the yeast system, I designed a library of repressor proteins with varying degradation rates, which I tested using a novel plant-based protein degradation assay, and used these to demonstrate the importance of their dynamics in plant development, particularly in root development.
In my graduate work, I designed degradation rate variants of the auxin-degraded repressor IAA14, a key repressor in lateral root formation. I tested their degradation rates, first in a synthetic yeast system, then in plants with a novel heat-shock based fluorescence assay. Once transformed into plants, I found that slower-degrading versions led to delayed development of lateral roots.
Figures from Guseman et al. Development. 2015.