Putting Rice on Full Blast?

by Ryan Costello, Sustainable Plant Systems – Landscape Design and Construction major

The pathogen at the stand is Magnoporthe oryzae, or the causal agent of rice blast disease. Its crime? Magnoporthe oryzae is the leading pathogen in cultivated rice. With rice being a major global food crop, rice blast disease is global threat.

This disease creates losses of 10%-30% globally, and outbreaks of this can cause regional epidemics that lead to starvation. An example of this would be the Irish Potato Famine, where the only staple crop of a region was destroyed by a pathogen, leading to the epidemic.

Magnoporthe oryzae should be stopped, shouldn’t it? Easier said than done.

The pathogen is relatively easily modified on a molecular or genetic scale, thus enabling scientists to study host-fungal pathogen interactions. There are now several cultivars that are resistant to the pathogen in circulation. These cultivars prove ineffective in the long term, however, as the pathogen can overcome the resistance in as little as 2-3 years.

The mutation and combination rate of Magnoporthe oryzae proves makes it to be an elusive foe for scientists. Over the last 6 years, genomic resources for the disease and related species have increased and now includes more than 30 strains globally.

This data shows many differences among the strains in gene content and organization of repetitive elements, meaning that they infect, and attack plants differently from one another.

We can only hope, with the help of new sequencing technologies, that we can find insight into creating more resistant hosts to this deadly global pathogen.

This blog post was an assignment for Societal Issues: Pesticides, Alternatives and the Environment (PLNTPTH 4597). The views expressed are those of the author and do not necessarily reflect the views of the class, Department of Plant Pathology or the instructor.

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