Canadian Forest Service Publications

The 124202 candidate effector of Melampsora larici-populina interacts with membranes in Nicotiana and Arabidopsis. 2016. Gaouar, O.; Morency, M.-J.; Letanneur, C.; Séguin, A.; Germain, H. Canadian Journal of Plant Pathology 38: 197-208.

Year: 2016

Issued by: Laurentian Forestry Centre

Catalog ID: 36633

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1080/07060661.2016.1153523

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Melampsora larici-populina (Mlp) is a parasitic fungus causing poplar leaf rust, a disease that threatens poplar plantations worldwide. Like other phytopathogens, Mlp translocates specialized proteins, called effectors, into host tissues and cells to eventually divert host resources. 124202 is a hypothetical Mlp effector selected through an in silico secretome analysis. It shares about 30% identity with the M. lini AvrM effector. Using heterologous systems, the objectives of this work were to assess if 124202 could mitigate Arabidopsis defense or potentiate Pseudomonas virulence and investigate its putative interaction partners in plants. Yeast two-hybrid screens identified three potential 124202 interactors in plants: lipoxygenase 2, synaptotagmin A, and quinolinate synthase. Expression of a fluorescently tagged 124202 protein in Nicotiana benthamiana and Arabidopsis thaliana showed that it could be associated with membranes but may also be found in the cytoplasm of host cells. Bacterial infection assays in wild-type and 124202-expressing Arabidopsis lines indicate that 124202 does not alter the susceptibility of Arabidopsis to Pseudomonas syringae pv. tomato DC3000. Overall, our results suggest that the function of 124202 might involve vesicle-mediated trafficking but is unlikely to quantifiably contribute to the suppression of plant immunity.

Plain Language Summary

This study suggests that it is very unlikely that the 124202 effector, which is a group of specialized proteins produced by the European poplar rust fungus, contributes to suppressing the poplar’s immunity to this pathogen.

Similarly to a number of fungal diseases, the European poplar rust fungus injects effectors into the cells of its host in order to divert its resources. The purpose of this research was to assess the ability of the 124202 effector to modulate the defence response of certain plants and to study its localization within plants.

Studying effectors could result in a better understanding of the defence mechanisms developed by poplars to protect themselves against exotic pests.