| Persimmon (Diospyros kaki L.), which belongs to the Ebenaceae family, is a Chinese special fruit and has many health functions. Carotenoid is the main pigment in persimmon fruit, which influences fruit color and nutrition quality due to its composition and content. In this paper, persimmon fruit was used as plant materials to establish the carotenoid profiles of persimmon fruit, analyze carotenoid contents of forty-six cultivars, clone five carotenoid synthesis related genes, study expression levels of related genes, and to analyze carotenoid contents and expression levels of related genes in fruit developmental stages. The results were as follows:1,9 kinds of carotenoid composition were identified (i. e. neoxanthin, violaxanthin, 9-cis-violaxanthin, lutein, zeaxanthin,β-cryptoxanthin,α-carotene,β-carotene, lycopene).β-Cryptoxanthin was the most abundant composition in the peel and flesh, which accounted for about 20-30% of total coloured carotenoids in both cultivars. The total carotenoid content in the flesh of persimmon fruits was between 194.61±15.94μg/100g FW and 1566.30±116.33μg/100g FW.β-Cryptoxanthin and zeaxanthin were the two most abundant carotenoids in the flesh of all persimmon fruits, accounting for 37.84-85.11% of total carotenoids. RE values also have great difference among cultivars, with the value between 8.62μg/100g FW and 90.57μg/100g FW. The region of cultivation and mature stage were also important factors, which influenced the carotenoid amounts and RE values of persimmon fruits.2,Five carotenoid synthesis related genes were isolated including DkPSY, DkPDS, DkZDS, DkLCYB and DkBCH. Among which, DkPSY and DkBCH cloned DNA full sequence, DkPDS and DkLCYB cloned cDNA full sequence, and DkZDS only got 3′ends partial sequence. DkPSY consisted of six extons and five introns, DkBCH had seven exons and six introns. Homology analysis showed that they all shared high similarities with these genes cloned from other plants. 3,'Xiaofangshi'was used as plant materials to examine the tissue-specific expression of isolated genes in young persimmon fruit. Expression level of five genes in the pulp was strongest and expression level of DkBCH was strongest among five genes analysed.'Fuyu'was used as plant materials to study five genes developmental expression level of flesh, the results revealed that DkPDS and DkZDS mRNA were basically constant growth, DkPSY and DkBCH mRNA at stage 4 and 3 had declined respectively and then continued to rise until reached the maximum, but DkLCYB mRNA had been maintained a low level.4,With the development of fruit,indicators of fruit quality trended similarly in'Niuxinshi'and'Nishimurawase', but only had differences in quantity. During fruit development, carotenoid content had been growing, and the content of'Nishimurawase'was always higher than that of'Niuxinshi'. In the mature stages of fruit, expression levels of DkPSY,DkPDS and DkZDS were high, together with synergy of each other, which lead to synthesize a lot of lycopene. On one hand, lycopene converted toα-carotene and xanthophyl which were very low and even under detection limit due to low expression levels of DkLCYE and DkLCYB; On the other hand, lycopene converted toβ-carotene,β-cryptoxanthin and zeaxanthin et al. Because of high expression level of DkBCH, accumulation of downstream related products increased and particularlyβ-cryptoxanthin, zeaxanthin and 9-cis-violaxanthin, so the final amount of lycopene was very little. |
PDF Full Text Request