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Sussex mathematicians model how rice blast disease kills enough crops to feed 60 million people yearly.

Identification of the Sln1 turgor-sensing kinase in M. oryzae (see Nature paper for full description)

A team of Mathematicians from Sussex have co-written a paper which has been published in the international science journal "Nature". 

The article entitled "A sensor kinase controls turgor-driven plant infection by the rice blast fungus”, emerged from a collaboration between experimentalists at The Sainsbury LaboratoryGregor Mendel Institute of Molecular Plant Biology, Austria and a team from the Mathematics Applied to Biology (MAB) research group at Sussex:  Anotida Madzvamuse, Professor of Mathematical and Computational Biology, Dr Chandrasekhar Venkataraman, Lecturer in Mathematics and Vanessa Styles, Professor of Mathematics.

Prof Anotida Madzvamuse said: "Shekar, Vanessa and also Dr Lauren Ryder from the Sainsbury Laboratory were all instrumental in modelling and experimentation and without them, this work would not have been possible. It has taken us a good seven years from start to finish and this paper is the first published work spanning those seven years!"

Rice blast is the most serious disease of rice and is caused by the fungus Magnaporthe oryzae. Each year, blast disease claims enough rice to feed 60 million people. The fungus also causes wheat blast which recently spread from South America to Bangladesh, threatening wheat production across South Asia.

Prof Madzvamuse continued:

“We were able to translate what was being observed in the experiments into a new mathematical model. With the biology described in mathematical terms, we were then able to help predict the point at which the fungus can reach a pressure threshold required to rupture the rice leaf, to infect the plant.

We hope that this may prove to be an important step toward developing disease control strategies in the future, which may have significant humanitarian benefits: improving crop yields to provide food for more people.”

To infect plants M.oryzae develops a domed-shaped infection cell called an appressorium that sticks to the leaf and ruptures the cuticle using huge invasive force - up to 40 times of a car tyre pressure, one of the highest pressures ever shown in a living cell.  

The six-year study has uncovered the existence of a sensor in appressoria which tells the fungus that the pressure threshold required to rupture the rice leaf has been reached.

Further mechanisms uncovered in the study allow the fungus to reposition a penetrative peg which is pressed against and physically breaks the leaf surface, allowing the fungus to enter and cause disease. 

Knowledge of this novel mechanism provides a platform for developing fungicides against blast, one of the deadliest crop killers.

The team of researchers used mathematical modelling, molecular genetics and biochemistry to crack the secret of the fungal pathogen.

Plant pathogenic fungi cause many of the world’s most devastating crop diseases.

Researchers had previously worked out how a group of proteins called septins enable the fungus to infect plants.

By revealing the existence of a turgor-sensing mechanism and the genetic networks that control polarisation of the fungus prior to infection, the group has assembled another critical piece in a research puzzle. 

Read the full article in Nature

Watch this video to find out how rice blast discovery will drive crop innovation  

By: Justine Charles
Last updated: Thursday, 17 October 2019