Abstract
In order to better understand differentiation from chloroplast to chromoplast, we are analyzing this mechanism during maturation in tomato fruits. At this conference, we would like to report our findings on vivid orange (vo) mutant (orange fruits) created by EMS treatment in Micro-Tom. When comparing the chromoplastic morphology of vo and wild types using an electron microscope, the vo mutant didn't have developing whirl structures and string structures with high electronic density. We then examined the content of carotenoid in fruits using HPLC analysis. Lycopene was not accumulated in vo mutant. But we found 52% more beta-carotene in vo compared with wild type. We analyzed the expression of carotenoid synthetic genes using RT-PCR in leaves and fruits of vo. We couldn't find any difference in the transcriptional level of these genes between vo and wild types. Now we are looking for point mutations in the carotenoid synthetic genes using the TILLING system, because a lack of transcripts was not identified as the cause of decreasing lycopene in vo.
