Navigation Links
Potato blight pathogenicity explained by genome plasticity

A team of researchers from Wageningen University report in this month's issue of Genome Research that they have identified a unique genetic fingerprint in the pathogen responsible for potato blight. Some strains of the pathogen possess multiple copies of a specific gene, while other strains possess only a single copy. Certain potato plants do not recognize strains of the pathogen with only the single gene copy, making them susceptible to infection. This is the first report of gene amplification in a non-bacterial organism that is associated with pathogenicity, and it provides insight into how plant pathogens tailor their genomes to adapt to their environments.

The potato late blight pathogen, known to scientists as Phytophthora infestans, is a fungus-like organism that was responsible for the Irish Potato Famine of the 1840s and continues to cause devastating agricultural losses worldwide today. Infected plants are characterized by dark lesions on the stems, leaves, and tubers; damage to the tuber surface allows other fungi and bacteria to enter and destroy the core, often resulting in a foul odor. P. infestans is related to approximately 65 other pathogens that cause similar damage to commercial crops as well as natural vegetation.

In the potato-Phytophthora system, the host-pathogen response has evolved in a highly specific way: resistance (R) genes from wild species, which are introduced into cultivated potato by breeding, are matched by avirulence (Avr) genes in Phytophthora. While many such gene matches are predicted, only a few have been confirmed by molecular and functional studies. Avr genes are thought to undergo rapid changes to evade detection by plants that possess R genes, which means that many strains of Phytophthora and potato are likely to be evolving at the present time.

"P. infestans is notorious for its ability to change in response to R g enes," says Dr. Francine Govers, the principal investigator on the project. "These changes are probably facilitated by its underlying genomic plasticity. Field isolates of P. infestans are known to be genetically highly variable."

Govers, along with colleagues Rays Jiang, Rob Weide, and Peter van de Vondervoort, set out to identify the genetic basis for the virulence of specific Dutch P. infestans strains. The outcome of their efforts was the identification of single gene, called pi3.4, that was present as a single, full-length copy in both the virulent and avirulent strains. They also identified multiple copies of pi3.4 only in the avirulent strain ?but, interestingly, these copies represented only part of the pi3.4 gene.

The authors speculate that the partial gene copies could function as a source of modules for generating new genes. These new genes could be produced by unequal crossing-over, or exchange of genetic material, during development. The partial copies may also serve as alternative protein-coding units, which allow the pathogen to produce a diverse array of proteins and, consequently, to adapt to its environment.

"Surprisingly, the pi3.4 gene does not code for an effector ?a small protein that elicits a defense response in plants," adds Govers. "Effectors are quite common in fungal and bacterial plant pathogens, including Phytophthora. But in our case, the gene appears to produce a large regulatory protein that exerts its effect by regulating the expression of other genes, possibly effector genes."

While the exact mechanism by which these partial gene copies function as a source of modular diversity remains to be resolved, this study highlights the importance of genome plasticity in evolution. Understanding genome plasticity as a mechanism for environmental response and ecological adaptation in pathogenic organisms has important implications. "The efforts of plan t breeders to obtain resistant varieties by introducing R genes, either by classical breeding or by genetic modification, may be a waste of time and resources when the genome dynamics of the pathogen population is not understood," says Govers. "Monitoring field populations of plant pathogens at the genome level will be instrumental for predicting the durability of R genes in crop plants."


'"/>

Source:Cold Spring Harbor Laboratory


Related biology news :

1. Researchers find gene that may be at root of potato blight
2. Lethal needle blight epidemic may be related to climate change
3. Cats indifference towards sugar explained
4. Pleasing plant shapes explained by new computer model
5. Evolution of irreducible complexity explained
6. Man and mouse share genome structures
7. Whole genome fine map of rice completed
8. Study finds more than one-third of human genome regulated by RNA
9. A bacterial genome reveals new targets to combat infectious disease
10. Scientists decipher genome of fungus that can cause life-threatening infections
11. Highly adaptable genome in gut bacterium key to intestinal health
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/1/2016)... June 1, 2016 Favorable Government ... Administration and Criminal Identification to Boost Global Biometrics System ... released TechSci Research report, " Global Biometrics Market ... Forecast and Opportunities, 2011 - 2021", the global biometrics ... 2021, on account of growing security concerns across various ...
(Date:5/16/2016)... NEW YORK , May 16, 2016   ... authentication solutions, today announced the opening of an IoT ... to strengthen and expand the development of embedded ... provides an unprecedented level of convenience and security with ... to authenticate one,s identity aside from DNA. EyeLock,s platform ...
(Date:5/3/2016)... May 3, 2016  Neurotechnology, a provider of ... MegaMatcher Automated Biometric Identification System (ABIS) , a ... projects. MegaMatcher ABIS can process multiple complex biometric ... combination of fingerprint, face or iris biometrics. It ... and MegaMatcher Accelerator , which have ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 23, 2016  Blueprint Bio, a company dedicated to ... medical community, has closed its Series A funding round, ... "We have received a commitment from Forentis ... need to meet our current goals," stated Matthew ... runway to complete validation on the current projects in ...
(Date:6/23/2016)... ... June 23, 2016 , ... ... regulatory and technical consulting, provides a free webinar on Performing Quality ... 13, 2016 at 12pm CT at no charge. , Incomplete investigations are still ...
(Date:6/22/2016)... June 22, 2016 Cell Applications, Inc. ... them to produce up to one billion human ... within one week. These high-quality, consistent stem cells ... cells and spend more time doing meaningful, relevant ... proprietary, high-volume manufacturing process that produces affordable, reliable ...
(Date:6/22/2016)... Philadelphia, PA (PRWEB) , ... June 22, 2016 ... ... the University City Science Center’s Port business incubator and current participant in the ... therapy and treatment for cancer patients. , Quantitative Radiology Solutions helps physicians ...
Breaking Biology Technology: