Table 1.
Enzymes and genes that regulate carotenoid accumulation in Brassica crops.
| Regulated Genes | Species | Major Changes | Genes (Gene Accession) | Color Change/Tissue | Reference |
|---|---|---|---|---|---|
| CRTISO | B. rapa | The mutant Br-oy protein cannot convert prolycopene to all- trans -lycopene. | BrOy (Bra031539) | white/yellow → orange inner leaf | [26,27] |
| The loss of BrCRTISO function leads to the accumulation of prolycopene. | Br-oy or BrCRTISO (Bra031539) | ||||
| Loss of BrWF3 function interferes with plastoglobules assembly and decreases expression levels of genes associated with carotenoid metabolism. | Brwf3 (Bra032957) | yellow → white/flower petal | [30] | ||
| The key factor for the pale-yellow color of petals was the decrease in esterified carotenoid content due to the loss of PYP function. | BrPYP (BraA02g037170.3C) | yellow → pale-yellow/flower petal | [31] | ||
| B. napus | The contents of carotenoids in petals and leaves of BnaCRTISO double mutant were reduced. In petals, the content of chalcone decreased, the content of some carotene (lycopene, α-carotene, γ-carotene) increased. |
BnaA09. CRTISO (BnaA09g49740D) BnaC08. CRTISO (BnaC08g44970D) |
yellow → milky white flower petals yellow → pale yellow leaves |
[32] | |
| B.oleracea | Carotenoid and chlorophyll levels were reduced in the mutant of BoaCRTISO. | BoaCRTISO (GenBank accession MN810158) | green → yellowing leaves | [33,34] | |
| ZEP | B. rapa | The loss of function of ZEP disrupts the metabolism of carotenoids and leads to the increase in total carotenoid accumulation. | Br-dyp1 (Bra037130) | yellow → dark yellow flower petal | [35] |
| B. napus | The abolishment of both genes led to a substantial increase in lutein content and a sharp decline in violaxanthin content in petals. |
BnaA09. ZEP (BnaA09g07610D) BnaC09. ZEP (BnaC07g16350D) |
yellow → orange flower petal | [36] | |
| CCD4 | B. napus | In yellow petals, a large amount of α-carotene, α-cryptoxanthin, β-cryptoxanthin, violaxanthin, 9-cis-violaxanthin, lutein, and cis-neoxanthinwere accumulated. | BnaC3.CCD4 (Bol029878) | white → yellow flower petal | [38] |
| B.oleracea | Not available. | BoCCD4 (Bol029878) | white/pale yellow → yellow flower petal | [39] | |
| These key genes may interact with BoCCD4 to jointly regulate carotenoid biosynthesis in petals. |
WRKY (Bo2g151880) SBP (Bo3g024180) |
[41] | |||
| OR | B.oleracea | The OR gene mutation confers the accumulation of high levels of β-carotene in various tissues normally devoid of carotenoids. | OR (GenBank accession DQ482460) | white → orange | [42] |
| B. rapa | The BrGOLDEN lines are rich in β-carotene and lutein. | BrGOLDEN (BraA09g007080.3C) | golden → light yellow inner leaf | [43] |