A paper detailing the team’s results was published in Science Signaling and is available online. In addition to Gelvin, co-authors include Rebecca Doerge, the Trent and Judith Anderson Distinguished Professor of Statistics; former postdoctoral research fellows and research associates graduate students Nagesh Sardesai, Huabang Chen and HoChul Yi; associate research scientist Lan-Ying Lee; visiting scholar Alexandra Stirnberg; former graduate student Gayla R. Olbricht; and undergraduate students Jacob Jeffries and Kia Xiong.
The team conducted genetic screens of Arabidopsis mutants hyper-susceptible to Agrobacterium infection to identify genes responsible for susceptibility. Through these screens the team discovered that a mutation in the gene MTF1 affected susceptibility to infection and genetic transformation. Plants in which MTF1 is suppressed were more susceptible to transformation.
The team also found that cytokinin, a plant hormone secreted by Agrobacteria, triggers a cascade of molecular events that lead to the suppression of MTFI and the activation of another gene that may aid the infection process. The gene that is activated encodes a protein that sits on the surface of the cell and may allow Agrobacterium to bind better to the plant cell, Gelvin said.
“We uncovered an entire molecular signal transduction pathway that reveals how the secreted cytokinins suppress the expression of the gene MTF1, which in turn increases the expression of the gene AT14A and a protein that makes a plant more susceptible to infection byAgrobacterium,” he said. “The end result is a plant that is much more susceptible to genetic transformation. Perhaps reducing the expression of MTF1 in other plants will have the same effect.”
MTF1 is important for normal plant development, so it cannot be completely knocked out or eliminated without killing the plant, but there are ways to reduce its expression, Gelvin said.
The team is working on developing technology to translate their findings into a tool that can reduce the expression of MTF1 and genetically transform a plant in one step, he said.