Nuclei change their positions in response to various
conditions such as development, biotic interactions,
and abiotic signals [38,39]. For example, nuclei in A.
thaliana leaves move away from strong light and relocate
to the side walls of the cell, whereas they move to the cell
bottom toward the leaf center plane during dark adaptation
[40]. This light-avoiding nuclear movement depends
on the blue-light receptor and F-actin [41]. Recent work
proposed that plastid relocation in response to strong blue
light, which is mediated by short actin filaments, generates
a motive force for light-avoiding nuclear movement
[42]. It has been suggested that myosin XI is involved in
the light-dependent plastid relocation, but this role is
currently controversial [43,44]. Light-induced nuclear
movement occurs normally in the myosin xi-i mutant,
whereas dark-induced nuclear movement is impaired
[36]. Therefore, myosin XI-i appears to be involved
in dark-induced nuclear movement.