BARD-funded research, recently published in the prestigious journal Nature Genetics, addresses for the first time “Tandem Kinase Proteins (TKPs) Atlas”. This research highlights the role of proteins that activate a localized suicide mechanism of cells attacked by pathogenic microorganisms in over 100 plant species, representing the entire plant kingdom. The research delves into the immune defence mechanisms of plants and provides a unique research foundation for the development and improvement of new plant varieties resistant to diseases. Tzion Fahima from the University of Haifa worked on this publication in partnership with Prof. Gitta Coaker from the Department of Plant Pathology at UC Davis.
Prof. Tzion Fahima, University of Haifa: “Understanding the evolutionary mechanisms of TKP proteins could provide important tools for future research, the development of disease-resistant plant varieties, and the enhancement of global food security. Identifying these proteins in 104 plant species, including commercial crops such as wheat, rice, and barley, highlights the potential for expanding their applications to other crops.
TKP proteins contribute to plants’ ability to deal with various pathogens, including bacteria and fungi, while reducing the reliance on chemical pesticides. Our findings shed new light on plant immune systems and could pave the way for the development of more environmentally friendly disease-resistant varieties.”
A Dual-Layered Immune Defense System in Plants
The researchers studied plant immune mechanisms and analyzed 104 genomes of various plant species, identifying 2,682 TKP proteins. The immune system of plants operates on a mechanism built from two layers of defense: the first layer recognizes pathogens through a system of receptors located on the outer surface of the cell, and the second, internal layer, is activated within the cells to protect against microorganisms attempting to invade. Unlike animals, plants do not have specialized mobile immune cells, like white blood cells or T-cells, which can move through the bloodstream to reach and protect the attacked tissue. Plants rely on unique mechanisms present in every cell and immune defense mechanisms that can be activated at the level of individual cells, attacked tissue, or even the entire plant.
The Role of TKPs in Plant Immunity
Plant immune proteins, such as TKPs, play a central role in the battle against diseases and protect the plant from pathogens. According to the Food and Agriculture Organization of the United Nations (FAO), the global annual crop loss due to plant diseases is about 10-20%, amounting to an estimated damage of about $200 billion per year, despite billions of dollars invested in conventional disease control practices, many of which are harmful to the consumer. These figures highlight even more the benefits of developing sustainable plant disease control methods by using solutions created by the natural evolution of plants.
The Mechanism of Pathogen Resistance: A Counter-Defense Model
The research by Professor Fahima and his colleagues revealed that more than 55% of TKP proteins were combined with other proteins, such as lectins, leucine-rich repeat, and stress-antifungal domains, which serve as decoys for the attack proteins of pathogens. These proteins, on their own, play an important role in activating the plant’s defense mechanisms against diseases.
Prof. Fahima and his team propose a model explaining the mechanism of action. During the co-evolution of host-parasite relationships, pathogens developed new attack mechanisms using unique proteins called effectors, which allow them to impair the activity of plant defense proteins and thus disable the plant’s immune system.
In response, plants developed a counter-defense system using those same defense proteins that are fused with TKPs. When a pathogen effector tries to disable its target protein, it is identified by the TKPs, which trigger a localized cell death suicide mechanism, leading to the death of the pathogen along with the attacked cells, halting the pathogen’s attack.
Implications for Agriculture and Food Security
This research highlights the significant potential for applying this mechanism in key agricultural crops such as wheat, barley, corn, and rice, and its importance in the fight against diseases that cause environmental, health, economic, and social damages. The researchers note that the results of the study will enable the development of more resistant plants through both traditional breeding methods and genetic engineering, thereby ensuring food security and reducing the heavy economic damages that farmers face annually worldwide. The publication of the “Tandem Kinase Proteins (TKPs) Atlas” provides a pioneering scientific foundation for studying plant immune mechanisms and opens new avenues for designing immune systems in plants that will help them deal with the challenges posed by various diseases.
The research involved PhD and postdoctoral students of Professor Tzion Fahima: Tamara Reveguk, Andrii Fatiukha, Evgeni Potapenko, Valentina Klimiuk, and the researcher Dr. Hanan Sela, from the Department of Evolutionary and Environmental Biology and the Institute of Evolution at the University of Haifa. Also involved were Professor Gitta L. Coaker from the University of California, Dr. Thomas Wicker from the University of Zurich in Switzerland, Dr. Yinghui Li from the Agricultural University of Sichuan in China, Dr. Ivan Reveguk from the Polytechnic School of Paris, and Professor Curtis Pozniak from the University of Saskatchewan in Canada.
