A study published in the open-access journal PLoS Biology reports that a plant protein has been identified that is associated with the plant’s ability to moderate resistance to infectious disease. Pamela Ronald (University of California, Davis) and colleagues hope that medical and agricultural researchers can make use of their findings, especially to improve global rice production.
Over the past three decades, Ronald and her colleagues have been studying the interaction between genetics and the manner in which rice plants respond to environmental factors. The researchers have created rice plants that are better at withstanding flooding, infectious diseases, and other environmental stresses.
There is a protein in rice (XA21), discovered by the Ronald lab in 1995, that functions as a “pathogen recognition receptor.” Receptors such as this are found in just about every higher organism, and they play an important role in managing the plant or animal response to infections. The XA21 receptor in rice plants, according to the researchers, has many similarities to proteins found in humans and other animals that control the innate immune response.
In both plans and animals, immune responses are crucial for the organism’s survival. If the human body fails to regulate these responses, it could lead to some cancers or other various diseases. In fact, most plants and animals have “negative regulators”, built-in biochemical moderators that keep an organism’s immune response from overreacting. In other words, the negative regulators ensure that the immune system only takes defensive measures against a perceived pathogen when it is truly necessary.
Ronald and her colleagues, as described in this recent study, have identified the XB15 protein – a negative regulator for the XA21 pathogen recognition receptor. “This finding gives us a better understanding of how the innate immune response is controlled,” clarifies Ronald.
The researchers have found that rice plants carrying an altered XB15 protein are better at resisting bacterial leaf blight, the cause of a serious bacterial disease in rice. In addition, it was observed that when the XB15 is excessively produced in rice plants with the XA21 resistance gene, the plant could actually become worse at defending against the disease.
“This information should help us to develop hardier, more productive rice plants that can better meet the worldwide demand for rice,” noted Ronald. Bacterial leaf blight has been the cause of reduced annual rice yields by as much as 60% in parts of Asia. “Rice is the staple food for more than half the world’s population,” Ronald concludes. “In developing countries, such significant crop losses translate directly into human suffering.”
Rice XB15, a protein phosphatase 2C, negatively regulates cell death and XA21-mediated innate immunity
Park CJ, Peng Y, Chen X, Dardick C, Ruan D, et al.
PLoS Biology (2008). 6(9): e231.
doi:10.1371/journal.pbio.0060231
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About PLoS Biology
PLoS Biology is an open-access, peer-reviewed general biology journal published by the Public Library of Science (PLoS), a nonprofit organization of scientists and physicians committed to making the world’s scientific and medical literature a public resource. New articles are published online weekly; issues are published monthly. For more information, visit http://www.plosbiology.org
About the Public Library of Science
The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world’s scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org
Written by: Peter M Crosta