The maize phytoene synthase gene family: Overlapping roles for carotenogenesis in endosperm, photomorphogenesis, and thermal stress tolerance
The maize phytoene synthase gene family: Overlapping roles for carotenogenesis in endosperm, photomorphogenesis, and thermal stress tolerance
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DOI：
10.1104/pp.108.122119
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发表时间：
2008-07-01
期刊：
影响因子：
7.4
通讯作者：
Wurtzel, Eleanore T.
中科院分区：
文献类型：
--
作者：
Li, Faqiang;Vallabhaneni, Ratnakar;Wurtzel, Eleanore T.
类胡萝卜素对于光合作用和光保护是必不可少的;它们还作为影响植物发育和生物/非生物胁迫反应的信号分子的前体。类胡萝卜素具有提高植物产量和营养品质的潜力，是代谢育种/工程的目标，特别是在包括主要粮食作物的禾本科（禾本科）中。根据遗传背景，玉米（Zea mays）胚乳类胡萝卜素含量变化，因此育种增强的类胡萝卜素水平一直受到关注。核编码的八氢番茄红素合成酶（PSY）是质体生物合成途径中的第一个关键步骤.玉米和其他禾本科植物中的基因家族包含三个旁系同源物，其特殊作用尚不清楚。玉米胚乳类胡萝卜素的积累需要PSY 1的表达。一种玉米抗体被用来本地化PSY 1淀粉体包膜膜，并确定PSY 1积累在发育胚乳中的类胡萝卜素积累。为了测试何时以及是否PSY转录水平与类胡萝卜素含量相关，利用了表现出遗传和化学多样性的玉米种质多样性收集。总类胡萝卜素含量与授粉后20 d的胚乳转录水平呈显著正相关，但与PSY 2和PSY 3的相关性不显著。以前未知的PSY 1转录丰度的时间为选择育种等位基因或适当控制引入的转基因提供了关键信息。PSY 1被意外地发现在光合组织中具有额外的作用，在那里它是黑暗中胡萝卜素生成和热胁迫耐受所必需的。叶胡萝卜素的生成需要光敏色素依赖和光敏色素非依赖的PSY 2光调节和非光调节的PSY 1表达。
Carotenoids are essential for photosynthesis and photoprotection; they also serve as precursors to signaling molecules that influence plant development and biotic/ abiotic stress responses. With potential to improve plant yield and nutritional quality, carotenoids are targets for metabolic breeding/ engineering, particularly in the Poaceae ( grass family), which includes the major food crops. Depending on genetic background, maize ( Zea mays) endosperm carotenoid content varies, and therefore breeding- enhanced carotenoid levels have been of ongoing interest. The first committed step in the plastid- localized biosynthetic pathway is mediated by the nuclear- encoded phytoene synthase ( PSY). The gene family in maize and other grasses contains three paralogs with specialized roles that are not well understood. Maize endosperm carotenoid accumulation requires PSY1 expression. A maize antibody was used to localize PSY1 to amyloplast envelope membranes and to determine PSY1 accumulation in relation to carotenoid accumulation in developing endosperm. To test when and if PSY transcript levels correlated with carotenoid content, advantage was taken of a maize germplasm diversity collection that exhibits genetic and chemical diversity. Total carotenoid content showed statistically significant correlation with endosperm transcript levels at 20 d after pollination for PSY1 but not PSY2 or PSY3. Timing of PSY1 transcript abundance, previously unknown, provides critical information for choosing breeding alleles or properly controlling introduced transgenes. PSY1 was unexpectedly found to have an additional role in photosynthetic tissue, where it was required for carotenogenesis in the dark and for heat stress tolerance. Leaf carotenogenesis was shown to require phytochrome- dependent and phytochrome- independent photoregulation of PSY2 plus nonphotoregulated PSY1 expression.