| Japanese apricot (Prunus mume Sieb. et Zucc.), originates in Southwestern China, has been domesticated in China more than 7000 years. Because of its prominent ornamental characteristics, Japanese apricot is loved by people for its rich colors, and widely cultivated in other East Asian countries as an early-blooming garden ornamental plant while most other ornamental plants in early spring. However, we have little information about the genetic mechanisms that underlie biological and ornamental traits of Japanese apricot. In order to investigate the mechanisms of flower color in Japanese apricot, we took the cv 'Fuban tiaozhi'as the plant materials. Firstly, we detected the types of pigments of white buds (WF) and red buds (RF). Then, we used a combination of two dimensional gel electrophoresis and mass spectromrtry (MALDI-TOF/TOF MS) to identify the differentially expressed proteome. RNA-seq was employed to study differentially expressed genes at the transcriptional level between WF and RF. The main results are as follows:1. To detect the pigment type and content of flower buds, we used the specific color reactions, UV-visible spectra and the pH differential method. The results demonstrated that the anthocyanins are the main pigment in petals of Japanese apricot. The red extract content of anthocyanins (0.0987 mg/g) is significant higher than white one (0.0376 mg/g). In the WF, the Chl a, Chl b, total Chl contents are 0.057 mg/g,0.134 mg/g,0.238 mg/g, respectively. And in the WF, the Chi a, Chl b, total Chl contents are 0.024 mg/g,0.060 mg/g,0.090 mg/g, respectively. Compared with the RF, the Chl contents of WF is significant higher. However, the contents and distributed of anthocyanins could be the reason that result the different color in 'Fuban Tiaozhi' Mei.2. We used a combination of 2-DE and MALDI-TOF/TOF MS to identify the differential proteins between the WF and the RF of the cv 'Fuban Tiaozhi'. The protein extraction followed by the method of TCA/acetone precipitation. More than 400 highly reproducible protein spots (P< 0.05) were detected and twenty-one proteins showed a greater than 2-fold difference. Among them, seven proteins are up-regulated while fourteen ones down-regulated. Using mass spectrometry and database searching, twenty proteins were demonstratively identified. Proteins identified were classified into eight functional classifications involved in energy and metabolism (6), transcription (2), cell structure (3), signaling pathway (1), secondary metabolism (1), protein synthesis (2), cell growth (1), defence (4). Energy and metabolism rank first, defence and cell structure related proteins were second and third, respectively. The proteomic results showed that ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit, inorganic pyrophosphatase, D-3-phosphoglycerate dehydrogenase related to energy. Actin and Beta tubulin belong to cell structure, and take part in pigment transport. Auxin-binding protein related to signaling pathway. The mRNA levels of twelve corresponding genes were detected using quantitative RT-PCR. Most of them are consistent, but differentially also exist.3. Differential expressed genes at the transcriptional were revealed by RNA-seq. The results showed that the number of clean tags 11.983,115 and 11,669,841, and the total number of base pairs from 571,822,209 to 587,172,635, remain in the WF and RF. There are 4.58 (39.24%) and 7.27 million tags (60.67%) mapped to reference gene and 5.01 (42.90%) and 7.91 million tags (65.99%) mapped the reference genome. A total of 960 genes, including 833 up-regulated and 127 down-regulated genes were identified. DEGs could classed into biosynthesis of secondary metabolites, phenylalanine metabolism, flavone and flavonol biosynthesis, structure of anthocyanins, carotenoid biosynthesis, plant hormone signal transduction, metabolic pathways, transcription factor and so on. |
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