Chrysanthemum is one of the most popular and economically important ornamental plants due to its huge diversity in growing habits, wide range of colors, and different patterns of flower. In the present study, we conducted the karyotype analysis in four naturally occurring genotypes of Chrysanthemum boreale. Karyotype studies based on the fluorescence in situ hybridization (FISH) using 5S and 45S rDNAs. Four chrysanthemum genoteyps showed an aneuploid chromosome number of 2n=18+2 (111016 and 111021) or a diploid of 2n=18 (121001 and 121002). All the genoteyps had the same karyotype formula of 14 metacentrics and 4 submetacentrics. In 111016, the chromosome length during somatic metaphase ranged from 3.11 ± 0.26 μm (shortest) to 3.94 ± 0.20 μm (longest), with a total length of 32.94 μm. The chromosome length at the mitotic metaphase ranged from 3.11 to 6.46 μm, with a total length of 32.94 μm in 111016 and 51.05, 32.81, and 46.00 μm in 111021, 121001, and 121002, respectively. The 5S rDNA and 45S rDNA signals recorded different in all four wildly grown genotypes of C. boreale. This information can be useful in cultivar improvement, as well as in elucidation of the evolution of the chrysanthemum.

Carotenoid isomerase (CRTISO) catalyzes the isomerization of prolycopene to all-trans-lycopene in the carotenoid biosynthetic pathway. We isolated two full-length cDNA gene, CuCRTISO and CuCRTISO-like, from Citrus unshiu. To confirm whether these two genes have the function of the carotenoid isomerase, The full-length cDNA of CuCRTISO and CuCRTISO-like gene, respectively, were fused with 35S promoter and NOS terminal region and then transformed into tomato CRTISO mutant, Tangerine, which shows orange fruit due to lack of carotenoid isomerase activity. The mature fruit color of the transgenic line expressing CuCRTISO gene changed from orange to red, which was similar to the fruit color of the tomato “Money Maker”. We also carried out HPLC analysis to detect all-trans lycopene, which is produced from prolycopene by carotenoid isomerase. In the transgenic line expressing CuCRTISO the all trans lycopene was detected from mature fruit but in the tangerine mutant several prolycopenes were detected from it. On the other hand, the transgenic line expression of CuCRTISO gene retained the orange-color fruit at the mature stage as Tangerine mutant. These studies indicate that the CuCRTISO gene has a function of carotenoid isomerase and also plays a role of it in other plant species, and that the CuCRTISO-like gene might be not enough to produce the all trans lycopene or has a another unknown function(s).

Carotenoid isomerase (CRTISO) catalyzes the isomerization of prolycopene to all-trans-lycopene in the carotenoid biosynthetic pathway. We isolated a full-length promoter region of CuCRTISO from Citrus unshiu. We determined if the promoter encoded organ-specific or developmental-specific expression, and identified possible cis-acting promoter elements. The full-length promoter and two truncated versions were fused to the β-glucuronidase (GUS) gene and transformed into Arabidopsis thaliana. Transgenic lines expressing the full-length promoter (pCiso-Prom1) and truncated promoters (pCiso-Prom2 and pCiso-Prom3) showed the same developmental and organ-specific activity. GUS expression was detected in the cotyledon and root at 5 and 10 days after germination, mature leaf, and anther. The CuCRTISO promoter contained several cis-acting elements involved in hormonal and environmental stress. Drought stress or abscisic acid treatment did not induce GUS expression in any transgenic lines. Heat stress induced GUS expression in the pCiso-Prom1 line; this promoter construct contains the heat-stress responsive element (HSE). Ethylene and cold-stress treatments induced GUS expression only in the pCiso-Prom3 line, although all transgenic lines contained the same cis-acting ethylene and low-temperature response elements. which could indicate the existence of unknown repressor element(s) in the CuCRTISO promoter. These studies indicate that CuCRTISO promoter activity is regulated in a developmental and organ-specific manner that responds to heat, cold, and ethylene. These results provide new insights into the role of cis-acting element(s) in CuCRTISO promoter activity. (This research was supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2010-0007627 and 2009-0094059), and by Golden Seed Project, Ministry of Agriculture, Food and Rural Affairs (MAFRA), Ministry of Oceans and Fisheries (MOF), Rural Development Administration (RDA) and Korea Forest Service (KFS), Republic of Korea)