Function of Nuclear Pore Complexes in Regulation of Plant Defense Signaling

Abstract

In eukaryotes, the nucleus is the regulatory center of cytogenetics and metabolism, and it is critical for fundamental biological processes, including DNA replication and transcription, protein synthesis, and biological macromolecule transportation. The eukaryotic nucleus is surrounded by a lipid bilayer called the nuclear envelope (NE), which creates a microenvironment for sophisticated cellular processes. The NE is perforated by the nuclear pore complex (NPC), which is the channel for biological macromolecule bi-directional transport between the nucleus and cytoplasm. It is well known that NPC is the spatial designer of the genome and the manager of genomic function. Moreover, the NPC is considered to be a platform for the continual adaptation and evolution of eukaryotes. So far, a number of nucleoporins required for plant-defense processes have been identified. Here, we first provide an overview of NPC organization in plants, and then discuss recent findings in the plant NPC to elaborate on and dissect the distinct defensive functions of different NPC subcomponents in plant immune defense, growth and development, hormone signaling, and temperature response. Nucleoporins located in different components of NPC have their unique functions, and the link between the NPC and nucleocytoplasmic trafficking promotes crosstalk of different defense signals in plants. It is necessary to explore appropriate components of the NPC as potential targets for the breeding of high-quality and broad spectrum resistance crop varieties.

Keywords: biological function; defense signaling; nuclear pore complex; nucleoporin; structure.

Figure 1

A model for the plant NPC structural organization and the role of plant NUPs in different biological processes. The NPCs consist of the following main components: scaffold nucleoporins include outer ring (blue), inner ring (yellow), the transmembrane ring nucleoporins (green), linker nucleoporins (purple), cytoplasmic filaments (dark) and nuclear basket (red), and central FG nucleoporins (dark purple). NUPs that have been functionally investigated in plants are underlined; and the left part lists some plant NUPs that have been reported to be involved in immune signaling (blue triangle), growth and development (green star), hormone response (purple diamond), and temperature response (orange cycle).