Department of Plant Nutrition, College of Resources and Environmental Sciences, China Agricultural University, MOE, Beijing 100193, China.
Guangdong Provincial Key Laboratory of Crop Genetic and Improvement, Crop Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
Plant Physiol. 2020 Sep;184(1):374-392. doi: 10.1104/pp.20.00378. Epub 2020 Jun 25.
Carotenoid cleavage dioxygenases (CCDs) drive carotenoid catabolism to produce various apocarotenoids and immediate derivatives with particular developmental, ecological, and agricultural importance. How genes evolved with species diversification and the resulting functional novelties in cereal crops have remained largely elusive. We constructed a unified four-clade phylogenetic tree of s, revealing a previously unanchored basal clade underwent highly dynamic duplication or loss events, even in the grass family. Different from cleavage sites of CCD8 and ZAXINONE SYNTHASE (ZAS), maize () ZmCCD10a cleaved differentially structured carotenoids at 5, 6 (5', 6') and 9, 10 (9', 10') positions, generating C (6-methyl-5-hepten-2-one) and C (geranylacetone, α-ionone, and β-ionone) apocarotenoids in Localized in plastids, ZmCCD10a cleaved neoxanthin, violaxanthin, antheraxathin, lutein, zeaxanthin, and β-carotene in planta, corroborating functional divergence of ZmCCD10a and ZAS. expression was dramatically stimulated in maize and teosinte ( ssp. , ssp. , , and ) roots by phosphate (Pi) limitation. silencing favored phosphorus retention in the root and reduced phosphorus and biomass accumulation in the shoot under low Pi. Overexpression of in Arabidopsis () enhanced plant tolerance to Pi limitation by preferential phosphorus allocation to the shoot. Thus, encodes a unique CCD facilitating plant tolerance to Pi limitation. Additionally, silencing and overexpression led to coherent alterations in expression of () and Pi transporters, and cis-regulation of expression by ZmPHR1;1 and ZmPHR1;2 implies a probable -involved regulatory pathway that adjusts Pi allocation.
类胡萝卜素双加氧酶(CCDs)驱动类胡萝卜素的分解代谢,产生各种具有特殊发育、生态和农业重要性的脱辅基类胡萝卜素和直接衍生物。基因如何随着物种多样化而进化,以及由此产生的谷类作物的功能新颖性,在很大程度上仍然难以捉摸。我们构建了一个统一的四分支系统发育树,揭示了以前未锚定的基础分支 ,经历了高度动态的复制或丢失事件,甚至在禾本科中也是如此。与 CCD8 和 ZAXINONE SYNTHASE(ZAS)的裂解位点不同,玉米()ZmCCD10a 在 5、6(5'、6')和 9、10(9'、10')位置裂解结构不同的类胡萝卜素,生成 C(6-甲基-5-庚烯-2-酮)和 C(香叶基丙酮、α-紫罗兰酮和β-紫罗兰酮)脱辅基类胡萝卜素,在质体中定位,ZmCCD10a 在体内裂解新黄质、 violaxanthin、花药黄质、叶黄素、玉米黄素和β-胡萝卜素,证实了 ZmCCD10a 和 ZAS 的功能分化。磷酸盐(Pi)限制强烈刺激玉米和大刍草( ssp. 、 ssp. 、 、和 )根中 的表达。 在低 Pi 条件下, 沉默有利于根系中磷的保留,并减少地上部分的磷和生物量积累。 在拟南芥()中过表达 增强了植物对 Pi 限制的耐受性,通过优先将磷分配到地上部分。因此, 编码了一种独特的 CCD,有助于植物耐受 Pi 限制。此外, 沉默和过表达导致 ()和 Pi 转运蛋白的表达发生一致改变,以及 ZmPHR1;1 和 ZmPHR1;2 对 表达的顺式调控,暗示可能涉及到一个由 调节的 Pi 分配途径。