Researchers may have discovered new information on rice blast, a disease that destroys enough rice to feed 60 million people annually.
A team from Rutgers University-New Brunswick conducted a genomic analysis of magnaporthales—an order of about 200 species of fungi including rice blast—to better understand the mechanism behind the infection process.
The researchers generated genome sequence data from five new Magnaporthales fungi, including non-pathogenic species, and performed comparative genome analysis of a total of 13 fungal species in the class to understand the evolutionary history of the Magnaporthales and of fungal pathogenesis. Some of the new members were discovered in the New Jersey Pine Barrens.
They also found that the fungus that causes the devastating disease in rice first became harmful around 21 million years ago. These findings could lead to more ways to fight or prevent crop and plant diseases, including new fungicides and quarantines that are more effective.
“With climate change, I think the rice blast problem can only get worse because this is a summer disease in warm climates where rice is grown,” Ning Zhang, study lead author and associate professor in the Department of Plant Biology and the Department of Biochemistry and Microbiology in the School of Environmental and Biological Sciences, said in a statement.
The scientists then genetically sequenced 21 related species that are less harmful or nonpathogenic than the rice blast fungus. The team found that proteins called secretomes that fungi secrete are particularly abundant in important pathogens like the rice blast fungus.
Based on previous research, the researchers discovered that the proteins may became more abundant over time, allowing the fungi to infect crops. The researchers then identified a list of genes that are abundant in pathogens, but less so in nonpathogens, so the abundant genes might promote pathogens that can infect crops. This will enable researchers to examine the mechanisms behind the infection process.
The researchers also found that related fungal pathogens also infect turfgrasses, causing summer patch and gray leaf spot that damage lawns and golf courses, as well as a new fungal disease found in wheat in Brazil that has spread to other nearby countries.
“The rice blast fungus has gotten a lot of attention in the past several decades but related species of fungi draw little attention, largely because they’re not as severe or not harmful,” Zhang said. “But they’re all genetically related and the relatives of severe pathogens have been little-studied. You have to know your relatives to have a holistic understanding of how the rice blast pathogen became strong and others did not.”
