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For better use of tea plant (Camellia sinensis) flower resources, biochemical components and contents of eight tea cultivars flowers were investigated. Volatile aromatic compounds were extracted by simultaneous distillation and solvent extraction (SDE) and determined using Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC-MS). The contents of tea polyphenols, amino acids, caffeine, soluble sugars and soluble proteins was assayed by colorimetric method with ferrous tartrate, ultraviolet spectrophotometric method, anthrone colorimetric method and coomassie brillient blue method, respectively. Among the eight cultivars flowers there were big difference in contents and numbers of volatile aromatic compounds. The greatest numbers of volatile aromatic compounds in flowers was 50, and the least numbers of volatile aromatic compounds in flowers was 9. The major constituents of volatile aromatic compounds in flowers included alkanes, alcohols, esters, ketones, aldehydes and alkenes. Acetophenone and tricosane were found in each cultivar flowers. However, The content of acetophenone, 2-heptanol, (S)-, 1,6-octadien-3-ol, 3,7dimethyl-, 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester and di-n-octyl phthalate were higher in some flowers. The result also indicated that tea flowers were rich in soluble sugars and soluble proteins.

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Somatic embryogenesis receptor-like kinases (SERKs) are receptor-like proteins that contain leucine-rich repeats and are involved in various signaling pathways. This study identified SERK family members in the Paulownia fortunei genome and analyzed their characteristics and expression profiles using bioinformatics methods. We identified 12 SERK genes with relatively conserved gene structures and motifs that were distributed unevenly on eight Paulownia chromosomes. The gene promoters contained various cis-acting elements that regulated the expression of the PfSERK genes in response to hormones and abiotic stresses. Synteny analysis indicated that 10 segmental duplication events had occurred during evolution of the PfSERK family. The expression profile of PfSERKs in various tissues of Paulownia fortunei was detected by quantitative real-time PCR (qRT-PCR). Many PfSERK genes can respond to drought and salt stress. Combined with RNA-seq and protein interaction network, it is speculated that PfSERK3/11 may participate in the occurrence of Paulownia witches' broom (PaWB) by regulating the plant height of Paulownia.

Paulownia witches’ broom (PaWB), caused by phytoplasmas, is the most devastating infectious disease of Paulownia. R2R3-MYB transcription factors (TF) have been reported to be involved in the plant’s response to infections caused by these pathogens, but a comprehensive study of the R2R3-MYB genes in Paulownia has not been reported. In this study, we identified 138 R2R3-MYB genes distributed on 20 chromosomes of Paulownia fortunei. These genes were classified into 27 subfamilies based on their gene structures and phylogenetic relationships, which indicated that they have various evolutionary relationships and have undergone rich segmental replication events. We determined the expression patterns of the 138 R2R3-MYB genes of P. fortunei by analyzing the RNA sequencing data and found that PfR2R3-MYB15 was significantly up-regulated in P. fortunei in response to phytoplasma infections. PfR2R3-MYB15 was cloned and overexpressed in Populus trichocarpa. The results show that its overexpression induced branching symptoms. Subsequently, the subcellular localization results showed that PfR2R3-MYB15 was located in the nucleus. Yeast two-hybrid and bimolecular fluorescence complementation experiments showed that PfR2R3-MYB15 interacted with PfTAB2. The analysis of the PfR2R3-MYB15 gene showed that it not only played an important role in plant branching, but also might participate in the biosynthesis of photosystem elements. Our results will provide a foundation for future studies of the R2R3-MYB TF family in Paulownia and other plants.