"Plant breeders often find that five or six years after their release, resistant plant varieties become susceptible because pathogens can evolve very quickly to overcome plant defenses," said Gregory Martin, Cornell professor of plant pathology, a scientist at the Boyce Thompson Institute for Plant Research (BTI) on the Cornell campus and the senior author of the research paper, published in the July 19 issue of the journal Nature. "However, every now and then, breeders develop a plant variety that stays resistant for 20 years or more."
Understanding why some varieties have more durable disease resistance is important to the development of more sustainable agricultural practices, he said.
The study by Cornell and BTI scientists describes how a single bacterial protein, AvrPtoB, which is injected by P. syringae into plant cells through a kind of molecular syringe, can overcome the plant's resistance. Normally, the plant's defense system looks out for such pathogens and, if detected, mounts an immune response to stave off disease. As part of this surveillance system, tomatoes carry a protein in their cells called Fen that helps detect P. syringae and trigger an immune response.
But some strains of P. syringae have evolved the AvrPtoB protein that mimics a tomato enzyme known as an E3 ubiquitin ligase, which tags proteins to be destroyed. Once injected, AvrPtoB binds the Fen protein, and the plant's own system eliminates it, allowing the bacteria to avoid detection and cause disease.
"This paper explains how a pathogen can evolve to escape detection," said lead author Tracy Rosebrock, a graduate student in Cornell's Department of Plant Pathology and BTI. "The bacterium has one specific protein that it uses to turn off the plant's immunity."
The researchers found that the Fen gene is present in both cultivated tomatoes and many wild tomato species, leading them to believe that the gene is likely ancient in origin and that many members of the tomato family have used it to resist P. syringae infections over the years. Since the Fen protein still detects AvrPtoB-like proteins from some strains of P. syringae, prompting an effective immune response, the researchers believe new P. syringae strains have only recently evolved a version of AvrPtoB that includes an E3 ubiquitin ligase enzyme that interferes with the plant's surveillance.
"This paper provides molecular data that supports the evolutionary 'arms race' theory" that as pathogens develop new ways to spread and attack organisms, the organisms in turn create novel defenses, each in a continuous battle to outdo the other, said Rosebrock.
The research was funded by the National Institutes of Health, the National Science Foundation and the Triad Foundation, a private charitable trust.
Blaine Friedlander | EurekAlert!
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences