Carotenoid cleavage dioxygenases (CCDs) drive carotenoid catabolism to produce various apocarotenoids and immediate derivatives with particular developmental, ecological, and agricultural importance. How CCD 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 CCDs, revealing a previously unanchored basal clade CCD10. CCD10 underwent highly dynamic duplication or loss events, even in the grass family. Different from cleavage sites of CCD8 and ZAXINONE SYNTHASE (ZAS), maize (Zea mays) ZmCCD10a cleaved differentially structured carotenoids at 5, 6 (5', 6') and 9, 10 (9', 10') positions, generating C₈ (6-methyl-5-hepten-2-one) and C₁₃ (geranylacetone, α-ionone, and β-ionone) apocarotenoids in Escherichia coli. Localized in plastids, ZmCCD10a cleaved neoxanthin, violaxanthin, antheraxathin, lutein, zeaxanthin, and β-carotene in planta, corroborating functional divergence of ZmCCD10a and ZAS. ZmCCD10a expression was dramatically stimulated in maize and teosinte (Z. mays ssp. parviglumis, Z. mays ssp. huehuetenangensis, Zea luxurians, and Zea diploperennis) roots by phosphate (Pi) limitation. ZmCCD10a silencing favored phosphorus retention in the root and reduced phosphorus and biomass accumulation in the shoot under low Pi. Overexpression of ZmCCD10a in Arabidopsis (Arabidopsis thaliana) enhanced plant tolerance to Pi limitation by preferential phosphorus allocation to the shoot. Thus, ZmCCD10a encodes a unique CCD facilitating plant tolerance to Pi limitation. Additionally, ZmCCD10a silencing and overexpression led to coherent alterations in expression of PHOSPHATE STARVATION RESPONSE REGULATOR 1 (PHR1) and Pi transporters, and cis-regulation of ZmCCD10a expression by ZmPHR1;1 and ZmPHR1;2 implies a probable ZmCCD10a-involved regulatory pathway that adjusts Pi allocation.

类胡萝卜素裂解双加氧酶 (CCD) 驱动类胡萝卜素分解代谢，产生各种类胡萝卜素和直接衍生物，具有特殊的发育、生态和农业重要性。 CCD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CCD的统一四分支系统发育树，揭示了先前未锚定的基础分支CCD10 。 CCD10经历了高度动态的复制或丢失事件，即使在草科植物中也是如此。与 CCD8 和 ZAXINONE SYNTHASE (ZAS) 的切割位点不同，玉米 ( Zea mays ) ZmCCD10a 在 5, 6 (5', 6') 和 9, 10 (9', 10') 位置切割差异结构的类胡萝卜素，生成 C ₈大肠杆菌中的 (6-甲基-5-庚烯-2-酮) 和 C ₁₃ (香叶基丙酮、α-紫罗兰酮和 β-紫罗兰酮) 类胡萝卜素。 ZmCCD10a 定位于质体，可裂解植物中的新黄质、紫黄质、炭黄质、叶黄素、玉米黄质和 β-胡萝卜素，证实了 ZmCCD10a 和 ZAS 的功能差异。通过磷酸盐 (Pi) 限制，玉米和大蜀黍（ Z. mays ssp. parviglumis 、 Z. mays ssp. Huehuetenangensis 、 Zea luxurians和Zea diloperennis ）根中的ZmCCD10a表达受到显着刺激。 ZmCCD10a沉默有利于磷在根中的保留，并减少低磷下地上部磷和生物量的积累。 ZmCCD10a在拟南芥 ( Arabidopsis thaliana ) 中的过表达通过优先向芽分配磷来增强植物对 Pi 限制的耐受性。 因此， ZmCCD10a编码了一种独特的 CCD，促进植物对 Pi 限制的耐受性。此外， ZmCCD10a沉默和过度表达导致磷酸盐饥饿反应调节器 1 ( PHR1 ) 和 Pi 转运蛋白表达的一致改变，并且 ZmPHR1;1 和 ZmPHR1;2 对 ZmCCD10a 表达的顺式调节意味着可能涉及ZmCCD10a的调节途径圆周率分配。