ORCID
- Littlejohn, George: 0000-0002-8768-2598
Abstract
Cell wall appositions (CWAs) are produced reactively by the plant immune system to arrest microbial invasion through the local inversion of plant cell growth. This process requires the controlled invagination of the plasma membrane (PM) in coordination with the export of barrier material to the volume between the plant PM and cell wall. Plant actin dynamics are essential to this response, but it remains unclear how exocytosis and the cytoskeleton are linked in space and time to form functional CWAs. Here, we show that actin-dependent trafficking to immune response sites of Arabidopsis thaliana delivers membrane-integrated FORMIN4, which in turn contributes to local cytoskeletal dynamics. Total internal reflection fluorescence (TIRF) microscopy combined with controlled induction of FORMIN4-GFP expression reveals a dynamic population of vesicular bodies that accumulate to form clusters at the PM through an actin-dependent process. Deactivation of FORMIN4 and its close homologs partially compromises subsequent defense and alters filamentous actin (F-actin) distribution at mature CWAs. The localization of FORMIN4 is stable and segregated from the dynamic traffic of the endosomal network. Moreover, the tessellation of FORMIN4 at the PM with meso-domains of PEN3 reveals a fine spatial segregation of destinations for actin-dependent immunity cargo. Together, our data suggest a model where FORMIN4 is a spatial feedback element in a multi-layered, temporally defined sequence of cytoskeletal response. This positional feedback makes a significant contribution to the distribution of actin filaments at the dynamic CWA boundary and to the outcomes of pre-invasion defense.
DOI
10.1016/j.cub.2018.05.014
Publication Date
2018-07-09
Publication Title
Curr Biol
Volume
28
Issue
13
Embargo Period
2018-07-21
Organisational Unit
School of Biological and Marine Sciences
Keywords
actin, callose, cytoskeleton, defense, formin, immunity, pen3, plant, powdery mildew, vesicle
First Page
2136
Last Page
2.14E+10
Recommended Citation
Sassmann, S., Rodrigues, C., Milne, S., Nenninger, A., Allwood, E., Littlejohn, G., Talbot, N., Soeller, C., Davies, B., Hussey, P., & Deeks, M. (2018) 'An Immune-Responsive Cytoskeletal-Plasma Membrane Feedback Loop in Plants.', Curr Biol, 28(13), pp. 2136-2.14E+10. Available at: https://doi.org/10.1016/j.cub.2018.05.014
