Crop diseases destroy more than 25 % of our food each year. Protecting crops with pesticides represents a considerable financial and environmental challenge. To develop new strategies to combat disease it is important to understand the molecular and cell biology of how microbial plant pathogens cause disease.
The oomycete pathogen Phytophthora infestans causes late blight, the number one disease of potato and tomato. It is a threat to global food security. It infects potato and tomato leaves by delivering so called ‘RxLR’ effector proteins into living host cells. We have found that RxLR proteins target and modify host proteins at various sites within plant cells (He et al 2020; Boevink et al 2020). We have found that many different processes in the plant are targeted for manipulation by these effectors.
P. infestans is unable to infect the model plant Arabidopsis. Arabidopsis is thus regarded as a nonhost plant, in that it is resistant to all genotypes of P. infestans. We are trying to determine why it is unable to infect Arabidopsis in order to understand how nonhost resistance works and thus how host range of this pathogen is determined. We are thus exploring whether P. infestans RxLR effectors are able to efficiently target their intended host proteins in the nonhost plant Arabidopsis. If they do, do they make the intended manipulations to those target proteins in order to suppress plant immunity? We are particularly interested in understanding the extent to which failure in effector function provides a barrier to infection. From a practical standpoint, if we find an Arabidopsis protein that is not efficiently targeted by a P. infestans RxLR effector, can we express that Arabidopsis protein in a host plant, such as potato? If we do, could this help to prevent late blight disease in this important crop?
This project will involve a range of molecular genetic techniques including gene and protein expression; genome and transcriptome analyses; cell biology to investigate effector-target interactions in host and nonhost plants; microbiological techniques and disease assays to investigate the consequence of effector action on plant immunity and susceptibility.
He et al (2020) All Roads Lead to susceptibility: the many modes of action of fungal and oomycete intracellular effectors. Plant Communications 1:100050
Boevink et al (2020) Devastating intimacy: the cell biology of plant-Phytophthora interactions. New Phytologist 228:445-458.
Second Supervisor: Dr Eleonor Gilroy https://www.hutton.ac.uk/staff/eleanor-gilroy