Abstract
In higher plants, Vacuole, which occupies most of a plant cell, plays important roles in a variety of plant growth and development. However, regulatory mechanism of vacuolar development has remained largely unknown.
We analyzed vacuolar aquaporins which transport water into the vacuoles and increase their volume.First, we analyzed the gene expression of a tobacco BY-2 vacuolar aquaporin,NtγTIP,using miniprotoplasts. The miniprotoplasts which are removed the vacuoles by centrifugation,start to regenerate the vacuoles as network-like structures.Subsequently,the network-like structures swelled to tube-like structures and finally the large vacuoles developed.In this process,NtγTIP was induced at the transition of network to tube-like structures and the large vacuolar development.Next,we prepared transgenic tobacco BY-2 cells that overexpress NtγTIP.In the NtγTIP-overexpressing cells,development of the tube-like vacuolar structures and large vacuoles were accelerated compared to the control ones. Furthermore, overproduction of NtγTIP promoted the vacuolar development and cell elongation. These results suggest that NtγTIP is involved in the vacuolar development.
