Giuliano G, Bartley G E, Scolnik P A
Ente Per Le Nuove Tecnologie, L'Energia E L'Ambiente, Casaccia Research Center, Rome, Italy.
Plant Cell. 1993 Apr;5(4):379-87. doi: 10.1105/tpc.5.4.379.
Phytoene synthase (Psy) and phytoene desaturase (Pds) are the first dedicated enzymes of the plant carotenoid biosynthesis pathway. We report here the organ-specific and temporal expression of PDS and PSY in tomato plants. Light increases the carotenoid content of seedlings but has little effect on PDS and PSY expression. Expression of both genes is induced in seedlings of the phytoene-accumulating mutant ghost and in wild-type seedlings treated with the Pds inhibitor norflurazon. Roots, which contain the lowest levels of carotenoids in the plant, have also the lowest levels of PDS and PSY expression. In flowers, expression of both genes and carotenoid content are higher in petals and anthers than in sepals and carpels. During flower development, expression of both PDS and PSY increases more than 10-fold immediately before anthesis. During fruit development, PSY expression increases more than 20-fold, but PDS expression increases less than threefold. We concluded that PSY and PDS are differentially regulated by stress and developmental mechanisms that control carotenoid biosynthesis in leaves, flowers, and fruits. We also report that PDS maps to chromosome 3, and thus it does not correspond to the GHOST locus, which maps to chromosome 11.
八氢番茄红素合酶（Psy）和八氢番茄红素去饱和酶（Pds）是植物类胡萝卜素生物合成途径中首先起作用的酶。我们在此报告番茄植株中PDS和PSY的器官特异性及时间表达情况。光照会增加幼苗中的类胡萝卜素含量，但对PDS和PSY的表达影响很小。在积累八氢番茄红素的突变体ghost的幼苗以及用Pds抑制剂氟草敏处理的野生型幼苗中，这两个基因的表达均被诱导。植物中类胡萝卜素含量最低的根，其PDS和PSY的表达水平也最低。在花中，花瓣和花药中这两个基因的表达以及类胡萝卜素含量均高于萼片和心皮。在花的发育过程中，就在开花前，PDS和PSY的表达均增加了10倍以上。在果实发育过程中，PSY的表达增加了20倍以上，但PDS的表达增加不到三倍。我们得出结论，PSY和PDS受控制叶片、花和果实中类胡萝卜素生物合成的应激和发育机制的差异调节。我们还报告说，PDS定位于第3号染色体，因此它与定位于第11号染色体的GHOST位点不对应。
