6c80

Publication Abstract from PubMed

During infection, plant pathogens secrete effector proteins to facilitate colonization. In comparison with our knowledge of bacterial effectors, the current understanding of how fungal effectors function is limited. In this study, we show that the effector AvrL567-A from the flax rust fungus Melampsora lini interacts with a flax cytosolic cytokinin oxidase, LuCKX1.1, using both yeast two-hybrid and in planta bimolecular fluorescence assays. Purified LuCKX1.1 protein shows catalytic activity against both N6-(Delta2-isopentenyl)-adenine (2iP) and trans-zeatin (tZ) substrates. Incubation of LuCKX1.1 with AvrL567-A results in increased catalytic activity against both substrates. The crystal structure of LuCKX1.1 and docking studies with AvrL567-A indicate that the AvrL567 binding site involves a flexible surface-exposed region that surrounds the cytokinin substrate access site, which may explain its effect in modulating LuCKX1.1 activity. Expression of AvrL567-A in transgenic flax plants gave rise to an epinastic leaf phenotype consistent with hormonal effects, although no difference in overall cytokinin levels was observed. We propose that, during infection, plant pathogens may differentially modify the levels of extracellular and intracellular cytokinins.

Structural and functional insights into the modulation of the activity of a flax cytokinin oxidase by flax rust effector AvrL567-A.,Wan L, Koeck M, Williams SJ, Ashton AR, Lawrence GJ, Sakakibara H, Kojima M, Bottcher C, Ericsson DJ, Hardham AR, Jones DA, Ellis JG, Kobe B, Dodds PN Mol Plant Pathol. 2018 Sep 22. doi: 10.1111/mpp.12749. PMID:30242946^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.