Nuclei in motion: movement and positioning of plant nuclei in development, signaling, symbiosis, and disease.

Anna H N Griffis,Xiao Zhou,Norman R Groves,Iris Meier

doi:10.3389/fpls.2014.00129

Abstract

While textbook figures imply nuclei as resting spheres at the center of idealized cells, this picture fits few real situations. Plant nuclei come in many shapes and sizes, and can be actively transported within the cell. In several contexts, this nuclear movement is tightly coupled to a developmental program, the response to an abiotic signal, or a cellular reprogramming during either mutualistic or parasitic plant–microbe interactions. While many such phenomena have been observed and carefully described, the underlying molecular mechanism and the functional significance of the nuclear movement are typically unknown. Here, we survey recent as well as older literature to provide a concise starting point for applying contemporary molecular, genetic and biochemical approaches to this fascinating, yet poorly understood phenomenon.

Highlights

In animals, nuclei are moved and positioned in a myriad of different cell types, developmental processes, and physiological situations
These nuclear movement and positioning events are regulated by the cytoskeleton, often in concert with nuclear envelope bridging LINC complexes, which link the cytoskeletal forces to the nucleoskeleton
Nuclear movement is integral to several plant processes, including pollen tube and root hair tip growth, trichome development, symbiotic and pathogenic plant–microbe interactions, and response to mechanical and light stimuli, as well as symmetric and asymmetric cell division

Summary

NUCLEAR MOVEMENT DURING DEVELOPMENT

POLLEN TUBE GROWTH The longest journey of plant nuclei is the migration of the vegetative nucleus (VN) and sperm cells (SCs) through pollen tubes. The VN precedes the GC/SCs (VN is closer to the growing pollen tube tip; Heslop-Harrison and HeslopHarrison, 1989a; McCue et al, 2011). MT depolymerizing drugs affected this order and increased the distance between the leading nucleus and the pollen tube apex, while higher concentrations increased VN-GC distance (Heslop-Harrison et al, 1988). Unlike in tobacco, both concentrations affected G. nivalis pollen tube growth (Heslop-Harrison et al, 1988). Despite interspecies differences, these studies suggest a MT network is responsible for MGU movement. As the Arabidopsis genome contains no dynein heavy chain genes, whether dyneins participate in MT-dependent MGU movement remains an open question (Lawrence et al, 2001)

Nuclear movement in plants

NUCLEAR MOVEMENT IN BIOTIC INTERACTIONS

NUCLEAR MOVEMENT IN ABIOTIC SIGNALING