Navigation Links
Researchers uncover sequence of major rice pathogen

In a genomics milestone, an international consortium of researchers has for the first time lifted the veil from a fungal plant pathogen by sequencing the genome ?or set of all genes ?of the most destructive enemy of rice: Magnaporthe grisea, the fungus that causes rice blast disease.

Dr. Ralph Dean, professor of plant pathology and director of North Carolina State University's Center for Integrated Fungal Research, is the lead author of a research paper that describes the M. grisea genome, published in the April 21 issue of the journal Nature.

It is estimated that rice blast, the leading cause of rice loss, is responsible each year for killing enough rice to feed 60 million people worldwide.

In the Nature paper, Dean and his co-authors shed some light on the adaptations required by a fungus to cause disease. The researchers identify novel receptors that allow the fungus to recognize its environment; secreted proteins that are likely used as offensive weapons to damage rice plants; and redundant, or duplicate, mechanisms that protect the fungus from efforts to fight against it.

"It's a clever system," Dean says. "If you have important genes, you tend to have a lot of them."

The paper also reports that the M. grisea genome contains retro-elements, or remnants of viruses, living in what Dean calls "hot spots" in the genome.

"These virus remnants live in discreet parts of the genome and have high rates of recombination, which may be why the fungus can evolve new strains so quickly," Dean says.

M. grisea undoubtedly produces toxins which may enable it to be a more effective pathogen. However our knowledge is limited to date, Dean says. The genome sequence should give researchers "a better idea of what types of genes are involved in making the toxin molecules," he says.

Some of these genes reside in clusters, Dean says, so one focus will be to take apart the clusters and learn more about toxins and their produ ction.

"The primary mission is to uncover the organism's weaknesses. You do that by building up an arsenal of information of what genes are involved in plant-pathogen interactions," Dean says.

In July 2002, Dean and researchers from the Whitehead Institute at MIT, now called the Broad Institute, issued a preliminary genome sequence of M. grisea, and made it publicly available so other researchers could work to solve the problems rice blast presents.

"That work decoded the string of letters that comprise the genome," Dean says. "This paper shows the work of the last two years in bringing this genome to life."

Bringing the genome to life means capturing the biological meaning of the genome, Dean says. To do this, he and his colleagues used two strategies: comparative genomics and functional genomics.

"In comparative genomics, you compare this genome to that of other organisms, other fungi," Dean says. "But fungi are very diverse; they've evolved tremendously. Fungi within the same family are as dissimilar as man is to a frog."

In functional genomics, Dean explains, scientists use comparative genomics to get hints about where to concentrate their study efforts.

"M. grisea contains about 11,000 genes, so you can't look at every one," he says. "The comparative study allows us to look at novel classes of genes and novel proteins and prioritize study efforts."

"The Genome Sequence of the Rice Blast Fungus Magnaporthe grisea" Authors: Ralph Dean, Thomas Mitchell, Resham Kulkarni, Huaqin Pan, Ignazio Carbone, Doug Brown, Yeon Yee, Nicole Donofrio, Robert Nicol, North Carolina State University; et al
Published: April 21, 2005, in Nature

Abstract: Magnaporthe grisea is the most destructive pathogen of rice worldwide and the principal model organism for elucidating the molecular basis of fungal disease of plants. Here, we report the draft sequence of the M. grisea genome. Analysis of the gene set prov ides an insight into the adaptations required by a fungus to cause disease. The genome encodes a large and diverse set of secreted proteins, including those defined by unusual carbohydrate-binding domains. This fungus also possesses an expanded family of G-protein-coupled receptors, several new virulence-associated genes, and large suites of enzymes involved in secondary metabolism. Consistent with a role in fungal pathogenesis, the expression of several of these genes is upregulated during the early stages of infection-related development. The M. grisea genome has been subject to invasion and proliferation of active transposable elements, reflecting the clonal nature of this fungus imposed by widespread rice cultivation.


Source:North Carolina State University

Related biology news :

1. Researchers discover way to make cells in the eye sensitive to light
2. Researchers find how protein allows insects to detect and respond to pheromones
3. Researchers Uncover Key Step In Manufacture of Memory Protein
4. Researchers reveal the infectious impact of salmon farms on wild salmon
5. Researchers identify target for cancer drugs
6. Researchers discover molecule that causes secondary stroke
7. Researchers find missing genes of ancient organism
8. Researchers trace evolution to relatively simple genetic changes
9. Researchers add new tool to tumor-treatment arsenal
10. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
11. VCU Researchers Identify Networks Of Genes Responding To Alcohol In The Brain
Post Your Comments:

(Date:11/17/2015)... PARIS , November 17, 2015 ... November 2015.   --> Paris from ... --> DERMALOG, the biometrics innovation leader, has invented the ... and fingerprints on the same scanning surface. Until now two ... fingerprints. Now one scanner can capture both on the same ...
(Date:11/17/2015)... EASTON, Mass. , Nov. 17, 2015 ... a leader in the development and sale of broadly ... the worldwide life sciences industry, today announced it has ... of its $5 million Private Placement (the "Offering"), increasing ... to $4,025,000.  One or more additional closings are expected ...
(Date:11/12/2015)... Mass. , Nov. 12, 2015  Arxspan ... Institute of MIT and Harvard for use of ... discovery information management tools. The partnership will support ... both biological and chemical research information internally and ... will be used for managing the Institute,s electronic ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... , Nov. 25, 2015  PharmAthene, Inc. (NYSE ... has adopted a stockholder rights plan (Rights Plan) in ... operating loss carryforwards (NOLs) under Section 382 of the ... --> PharmAthene,s use of its NOLs could ... change" as defined in Section 382 of the Code. ...
(Date:11/25/2015)... 25, 2015 Studies reveal the ... plaque and pave the way for more effective treatment for ...     --> --> ... health problems in cats, yet relatively little was understood about ... studies have been conducted by researchers from the WALTHAM Centre ...
(Date:11/25/2015)... , Nov. 25, 2015  Neurocrine Biosciences, Inc. (Nasdaq: ... , President and CEO of Neurocrine Biosciences, will be ... in New York . ... the website approximately 5 minutes prior to the presentation ... of the presentation will be available on the website ...
(Date:11/25/2015)... ... November 25, 2015 , ... A long-standing ... Aerospace Professionals (OPBAP) has been formalized with the signing of a Memorandum of ... with OPBAP leaders Capt. Karl Minter and Capt. Albert Glenn Tuesday, November 24, ...
Breaking Biology Technology: