Organelle biogenesis and function in plants

All eukaryotic cells contain an endomembrane system with functionally distinct membrane-bound organelles, including the endoplasmic reticulum (ER), Golgi apparatus, trans-Golgi network (TGN), prevacuolar compartment or multivesicular body (PVC/MVB) and vacuole or lysosome. These organelles are generated accurately and efficiently in a well-organized way so as to exert their essential functions in protein transport, plant growth and responses to the environment. Since the year 2000, great progress has been achieved by the Chinese scientists toward our understanding on organelle biogenesis and function in plants. In this review, representative research findings in plant protein trafficking contributed by Chinese scientists are first introduced. Due to the functional importance of PVCs/MVBs, we then focus on the identification and characterization of PVCs/MVBs as well as the mechanisms underlying their biogenesis as regulated by the ESCRT (endosomal sorting complexes required for transport) machinery, especially by the plant-unique ESCRT component, FREE1 (FYVE domain protein required for endosomal sorting 1). In addition, some Chinese scientists recently perform a whole-cell electron tomography analysis in the endomembrane system of root cells to first propose a new MVB-derived vacuole biogenesis model for future investigation of the underlying mechanisms of vacuole formation. Finally, we summarize current research progress on organelle (PVC/MVB and vacuole) biogenesis and function in plants and present future perspectives in this research field.