Location: Crop Production and Pest Control Research
2022 Annual Report
Accomplishments
1. Identification of candidate effector proteins from the maize tar spot pathogen Phyllachora maydis and determination of their cellular locations. Plants have a sophisticated immune system capable of detecting and conferring resistance to a variety of plant pathogens. During the infection process, pathogens inject proteins known as ‘effectors’ into the plant host cell to “shut-off” the plant immune system, thereby promoting pathogen growth and disease and consequently reducing crop yields. Therefore, studying how plant pathogens use these proteins during infection is important as it often provides insight into how pathogens reduce crop yields. One such fungal pathogen of corn known as Phyllachora maydis injects ‘effector’ proteins into corn leaves resulting in a disease called tar spot. Importantly, tar spot disease can significantly reduce overall corn yields and, in turn, induce severe financial penalties to farmers. Therefore, there is an urgent need to investigate how this fungal pathogen uses its effector proteins to infect corn leaves. Here, we show that this fungal pathogen injects ‘effector’ proteins into host cells, where they specifically target plant organelles such as the nucleus and chloroplast. ARS researchers in West Lafayette, Indiana, therefore, hypothesized this fungal pathogen interferes with and manipulate host immune responses by targeting the plant organelles. Our work presented here provides valuable insights into the host processes potentially manipulated by this fungal pathogen and lays the foundation for generating testable hypotheses for future work. A manuscript describing these results was recently published in Phytopathology.
