紫玉米是玉米栽培品种的一个变种，因其富含花青素，故而呈现独特的色泽、丰富的营养价值。花青素是决定紫玉米显色的重要色素，对植物生长有重要调节作用，对人类健康也存在诸多益处。研究表明，农作物籽粒颜色的深度与其营养品质的相关性较强，颜色深可一定程度反映该农作物的营养价值高。因此研究紫玉米中花青素的形成和积累机制具有较高的价值。本研究以紫玉米（PC-963）、黄玉米（Chang7-2）和乳白玉米（530）为材料，通过转录组分析比较了PC-963籽粒不同发育阶段参与花青素合成的相关基因的表达差异；克隆和分析了PC-963中烯醇化酶编码基因ZmENO2；以PC-963和530为亲本，获得F₁代浅紫玉米（LC-963）和F₂分离群体，并对玉米籽粒颜色性状的遗传性进行了初步分析。具体的研究结果如下：

（1）对授粉后生长不同时期的籽粒进行观察发现，在授粉后第14天颜色发生变化，色素的沉积始于远胚端。随着籽粒的生长，色素逐渐在糊粉层沉积。通过检测籽粒中花色苷含量发现，在34 DAP（Day after pollination）籽粒花色苷含量占比最大。

（2）对10 DAP、14 DAP、34 DAP的籽粒进行转录组分析，共筛选到17168个差异表达基因（Differentially expressed genes, DEGs）（7564个上调，9604个下调），并主要显著富集在“苯丙素生物合成”、“次生代谢产物生物合成”和“植物激素信号转导”途径中。在花青素积累途径中，有72%的结构基因发生上调表达，有30%的转录因子也得到显著富集。此外，植物激素基因的差异表达也可能是影响花青素积累的一个重要因素。

（3）克隆了PC-963 ZmENO2基因。通过ZmENO2与AtENO2同源性分析，发现二者相似度高达88.5%。qPCR结果显示，ZmENO2在检测的各组织（茎、底叶、中叶、顶叶、侧根、雄穗、花丝和苞叶）样品中均表达，其表达丰度在抽雄期的雄穗、散粉期的侧根和吐丝期的花丝中相对较高。此外ZmENO2表达量与籽粒发育过程中花色苷含量的变化呈负相关，推测ZmENO2可能是调节玉米籽粒颜色的候选基因。

（4）通过杂交实验获得F₁代LC-963（父本：PC-963；母本：530），次年进行LC-963单株自交，获取F₂代。根据F₂代的表型和分离比可知，玉米籽粒颜色性状受多对等位基因控制，并进一步推测出F₁代LC-963基因型为A₁_A₂_C₁_C₂_R₁_Bz₁Bz₁Bz₂Bz₂In₁_Pr₁_。

综上所述，本研究从转录组水平解析了紫玉米籽粒发育过程中花青素积累的机制，从基因水平初步探索了ZmENO2与籽粒颜色变化的关系，从遗传水平分析了玉米籽粒颜色性状的遗传。这为今后紫玉米花青素合成和积累的研究以及富含花青素的植物新品种的创制提供了依据。

Purple corn is a variety of corn cultivar, because it is rich in anthocyanidins, it presents a unique color and has rich nutritional value. Anthocyanidins are important pigments that cause plant tissues to develop colors. They have attracted much attention due to their crucial regulatory roles in plant growth as well as their health benefits. It shown that the nutritional quality of crops is closely related to the grains color, and the darker the color, the higher the nutritional value. Therefore, it is valuable to study the formation mechanism of anthocyanidins in purple corn. In this study, purple corn (PC-963), yellow corn (Chang 7-2) and ivory corn (530) were used as materials. Transcriptome analysis was used to compare the expression differences of anthocyanidins biosynthesis related genes in PC-963 at different developmental stages; The enolase gene ZmENO2 in PC-963 was cloned and analyzed; The F₁ Lilac corn (LC-963) and F₂ segregation population were obtained by using PC-963and 530 as parents, and the heredity of corn grains color character was preliminarily speculated. The specific results are as follows:

(1) Observations of grains at different stages of growth after pollination showed that the color of seeds changed on the 14th day after pollination. Pigments started from the distal end of the embryo and gradually deposited in the aleurone layer with the development of grains. Through the detection of anthocyanin content in grains, it was found that the anthocyanin content of grains accounted for the largest proportion at 34 DAP (Day after pollination).

(2) Transcriptome analysis of 10 DAP, 14 DAP and 34 DAP seeds revealed 17168 Differentially expressed genes (7564 up-regulated and 9604 down-regulated), which were mainly concentrated in “Phenylpropanoid biosynthesis”, “Biosynthesis of secondary metabolites”, and “Plant hormone signal transduction”. In the anthocyanin accumulation pathway, 72% of structural genes were up-regulated, and 30% of transcription factors were significantly enriched. Moreover, the differential expression of phytohormone genes might also be an important factor affecting anthocyanidin accumulation.

(3) ZmENO2 was cloned from PC-963. Homology analysis of ZmENO2 and AtENO2 showed that the similarity between them is as high as 88.5%. The qPCR results showed that ZmENO2 was expressed in all the tissue (Stem, bottom leaf, middle leaf, parietal lobe, lateral root, tassel, faliment, bract) samples, the expression abundance was the higher in tassel stage, lateral root stage and filament stage. In addition, the expression level of ZmENO2 was inversely proportional to the change of anthocyanin content during grain development, suggesting that ZmENO2 might be a candidate gene controlling the color of corn grains.

(4) The F₁ generation of LC-963 was obtained by using PC-963 as the parent and 530 as the mother. LC-963 was self-crossed by single plant to obtain the F₂ segregation population. According to the phenotype and separation ratio of the F₂ segregation population, the traits of color in corn grains were controlled by multiple pairs of alleles, and it was further speculated that the genotype of LC-963 was A₁_A₂_C₁_C₂_R₁_Bz₁Bz₁Bz₂Bz₂In₁_Pr₁_.

In summary, the transcriptome level explained the anthocyanin accumulation mechanism during the seed development of purple corn. The relationship between ZmENO2 and the change of grains color was preliminarily explored at the gene level. The heredity of corn grains color character was analyzed from the genetic level. The results provided a basis for the study on the synthesis and accumulation of anthocyanins in purple corn and the creation of new anthocyanidins-rich plant varieties.