Their research is part basic science, investigating the bacterium's resilience in a hostile environment – coffee leaves – and part biotech, seeing whether the bacterium inhibits the development of a pathogen that causes severe losses to coffee growers.
A study supported by FAPESP analyzed the potential of a bacterium for biological control of the fungus Hemileia vastatrix, which causes coffee rust, a major challenge for Brazilian coffee growers. An article on the study is published in the journal BMC Microbiology.
The symptoms of coffee rust are yellow spots like burn marks on the leaves of the plant. The disease impairs photosynthesis, making foliage wither and preventing bean-producing cherries from growing until the tree resembles a skeleton. It is typically controlled by the use of copper-based pesticides, which can have adverse effects on the environment. "This was a basic science study, in which we set out to understand the behavior of bacteria that inhabit the leaves of coffee trees. First of all, there are several compounds that are harmful to bacteria and can be used to attack them," said Jorge Maurício Costa Mondego, last author of the article.
Mondego is a researcher affiliated with the Center for Plant Genetics at the Campinas Institute of Agronomy (IAC). He has a PhD in genetics and molecular biology from the State University of Campinas (UNICAMP) in São Paulo state, Brazil. "Second, leaves are environments that undergo significant environmental pressures, such as sunlight and rain. We wanted to understand how bacteria that live on coffee leaves can withstand both the compounds produced by the coffee plant and the stresses of rain and sun," he said.
Besides this basic science front, the study also addressed applied science challenges. The researchers decided to find out whether bacteria that inhabit coffee leaves can combat the fungus that causes coffee rust. The first step consisted of identifying the expressed sequence tags (ESTs) of Coffea arabica and C. canephora produced by the Brazilian Coffee Genome Project (Projeto Genoma EST-Café) funded by FAPESP and the Brazilian Agricultural Research Corporation (EMBRAPA). "I was the first author, alongside Ramon Vidal, a professor at UNICAMP, of an…