Mar. 28, 2018
The Laboratory of Plant–Microorganism Interactions of the Institute of Molecular and Cellular Biology of Rosario has made new advancements in the study of the mechanisms of plant-pathogen interactions. The group has vast experience in the study of a disease known as citrus canker, caused by the Xanthomonas citri subsp. Citri bacteria, which is currently one of the major phytosanitary problems faced by Argentinian citrus.
Until now, no citrus plants are resistant to this disease. It includes all citrus plants, such as lemons, oranges, tangerines, peaches and grapefruits. A recent study on citrus canker was published in the Journal of Experimental Botany, in collaboration with researchers from Max Planck Institutes of Germany and KAUST of Saudi Arabia. The study revealed a new mechanism that uses Xanthomonas to survive on the surface of leaves.
The researcher, Natalia Gottig, highlighted one of the axis in the study, where the group focused on the adherence of the bacteria to the plant, a fundamental stage in the development of the disease, and the capacity of associating with other cells of the same bacteria and forming a community named biofilm.
“This growth in the form of biofilm allows the bacteria to survive better in adverse environmental conditions and sustain itself for longer periods on the vegetable’s surface, which intensifies its infectious capacity and spreads the infection,” emphasized Gottig.
Gottig demonstrated that this pathogen produces a sugar, called trehalose, which is an osmoprotective substance and important for the development of citrus canker, which allows the bacteria to survive in situations of environmental stress on the vegetable’s surface.
Besides this, throughout the metabolic studies and proteomic, it was demonstrated that the trehalose produced by the bacteria modifies the physiology of the tissue in a way that favors the growth of the pathogen, and thus encourages the development of this disease.
However, this sugar is a double-edged sword. Once the citrus plants are already evolved, they are capable of detecting this molecule and triggering responses of defense with the goal of countering the pathogen attack and, in this way, control the establishment of this disease.
In this work, the dual role of trehalose was characterized by the interaction between plant and pathogen. “The discovery of this molecule is capable of alerting the defense mechanisms in citrus plants, allowing the development of new strategies that will use this sugar for the control of citrus canker and other citrus diseases,” the researcher concluded.