Our Mission

Our Mission

• The Ronald laboratory investigates fundamental
  processes of grasses such as rice and switchgrass. Applications of our
  research can enhance ecological farming practices by reducing the
  amounts of pesticides and herbicides in the environment and by reducing
  dependence on fossil fuels.

Our Research

•     Rice is the primary food for more than 3 billion people around the world.
•     We are using genomic, proteomic and informatic tools to study rice perception, signaling and response to bacterial and fungal pathogens, and submergence stress. Because of its diploid genetics, small genome size, extensive genetic map, available genome sequence, and relative ease of transformation, rice is considered a model monocot. Therefore the structural and functional analysis of rice has broad practical implications for the other economically important cereals, such as switchgrass.

Disease resistance

•     It is estimated that 50% of the potential yield of the world rice crop is lost to diseases caused by bacteria, fungi and viruses. One of the most serious bacterial diseases of rice in Africa and Asia is bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) (shown at left). BLB is one of the oldest recorded rice diseases and has been problematic for over a century. The most serious fungal disease of rice is blast caused by the fungus Pyricularia oryzae. The rice/ Xoo and blast interactions present useful genetic systems for studying interactions between two organisms and has direct relevance to the cultivation of important food crops.

    Projects include the cloning and characterization of disease resistance genes to BLB and blast, analysis of transgenic plants expressing these genes, identification of pathogen produced signal molecules that interact with disease resistance gene products, biochemical analysis of disease resistance gene products and their interacting proteins, studies of the evolution of disease resistance loci, and analysis of sequences expressed during the rice defense response.

Submergence tolerance

    Globally, rice is the most important food for humans, and each year millions of small farmers in the poorest areas of the world lose their entire crops to flooding,. Approximately one fourth of the global rice crop is grown in rainfed, lowland plots that are prone to seasonal flooding. These seasonal flash floods are extremely unpredictable and may occur at any growth stage of the rice crop. While rice is the only cereal crop that can withstand submergence at all, most rice varieties will die if fully submerged for too long. When the plant is covered with water, its oxygen and carbon dioxide supplies are reduced, which interferes with photosynthesis and respiration. Because the submerged plants lack the air and sunlight they need to function, growth is inhibited and the plants will die if they remain underwater for more than four days.

    During any given year, yield losses resulting from flooding in these lowland areas may range from 10 percent to total destruction, depending on the water depth, age of the plant, how long the plants are submerged, water temperature, rate of nitrogen fertilizer use and other environmental factors. Annual crop loss has been estimated at more than $1 billion.

    Our research team has identified a gene that confers submergence tolerance to rice and have introduced this gene into agronomically important varieties. The resulting rice plants are not only tolerant of being submerged in water but also produced high yields and retained other beneficial crop qualities. Development of submergence-tolerant varieties for commercial production in Laos, Bangladesh and India is now well underway. Cultivation of the new variety is expected to increase food security for 70 million of the world's poorest people, and may reduce yield losses from weeds in areas like the United States where rice is seeded in flooded fields.

    In addition to providing a more stable supply of rice in developing countries, we hope that the new gene will be useful in suppressing weeds and reducing herbicide applications for conventional and organic rice farmers in developed countries like the United States. If water can be left on the rice for an additional week, it is expected that weed populations will be reduced.

Bioenergy

    Cost efficient conversion of lignocellulosic biomass into bioethanol requires changes in cell wall characteristics and yield.  The Poaceae family, represented by rice, holds great promise to the bio-fuel industry, which include all cereals and several high potential bioenergy crops such as switchgrass (Panicum virgatum L.). Currently used primarily for forage and erosion control, switchgrass has received relatively modest attention from breeders and has only begun to be characterized on a molecular level. There is now a tremendous opportunity to leverage genomic information from other grass species such as rice for switchgrass improvement. The Ronald lab is using a variety of approaches, together with collaborators, to investigate cell wall synthesis and function. For more information, please see our JBEI and DOE-USDA- funded projects.

    For more technical information you can browse our list of selected publications and links.