Fujiwara Makoto

In vascular plants, non-photosynthetic plastids, such as amyloplasts for starch storage in tubers and root tips and leucoplasts referred to as non-coloured plastids in roots and other non-green tissues, are controlled by distinct mechanisms from those for leaf chloroplasts in terms of the structure and behaviour. To elucidate these issues, we constructed transgenic Arabidopsis plants, in which the N-terminal plastid targeting sequence from the plastid division factor AtFtsZ1-1 or the Rubisco small subunit is fused to the N-terminus of the green fluorescent protein or its variants and expressed stably under the control of the Cauliflower mosaic virus 35S promoter. By epifluorescence microscopy using living tissues of these plants, we found that leucoplasts in seed integuments take highly filamentous forms and also produce stromules at high frequency. Furthermore, leucoplasts at the onset of amyloplast differentiation were found to display amoeboid-like shape and motility, as revealed by time-lapse epifluorescence microscopy.