Transcriptome analysis to identify candidate genes related to chlorogenic acid biosynthesis during development of Korla fragrant pear in Xinjiang

Korla fragrant pear(KFP)with special fragrance is a unique cultivar in Xinjiang,China.In order to explore the biosynthesis molecular mechanism of chlorogenic acid(CGA)in KFP,the samples at different development periods were collected for transcriptome analysis.High performance liquid chromatography analysis showed that CGA contents of KFP at 88,118 and 163 days after full bloom were(20.96±1.84),(12.01±0.91)and(7.16±0.41)mg/100 g,respectively,and decreased with the fruit development.Pears from these typical 3 periods were selected for de novo transcriptome assemble and 68059 unigenes were assembled from 444037960 clean reads.One‘phenylpropanoid biosynthesis’pathway including 57 unigenes,11 PALs,1 PTAL,64CLs,9 C4Hs,25 HCTs and 5 C3’Hs related to CGA biosynthesis was determined.It was found that the expression levels of 11 differentially expressed genes including 1 PAL,2 C4Hs,34CLs and 5 HCTs were consistent with the change of CGA content.Quantitative polymerase chain reaction analysis further showed that 8 unigenes involved in CGA biosynthesis were consistent with the RNA-seq data.These findings will provide a comprehensive understanding and valuable information on the genetic engineering and molecular breeding in KFP.

Molecular and Biochemical Evidence for Phenylpropanoid Synthesis and Presence of Wall-linked Phenolics in Cotton Fibers

The mature cotton （Gossypium hirsutum L.） fiber is a single cell with a typically thickened secondary cell wall. The aim of this research was to use molecular, spectroscopic and chemical techniques to investigate the possible occurrence of previously overlooked accumulation of phenolics during secondary cell wall formation in cotton fibers. Relative quantitative reverse transcription-polymerase chain reaction analysis showed that GhCAD6 and GhCAD1 were predominantly expressed among seven gene homologs, only GhCAD6 was up-regulated during secondary wall formation in cotton fibers. Phylogenic analysis revealed that GhCAD6 belonged to Class I and was proposed to have a major role in monolignol biosynthesis, and GhCAD1 belonged to Class III and was proposed to have a compensatory mechanism for monolignol biosynthesis. Amino acid sequence comparison showed that the cofactor binding sites of GhCADs were highly conserved with high similarity and identity to bona fide cinnamyl alcohol dehydrogenases. The substrate binding site of GhCAD1 is different from GhCAD6. This difference was confirmed by the different catalytic activities observed with the enzymes. Cell wall auto-fluorescence, Fourier transform infrared spectroscopy （FTIR）, high-performance liquid chromatography （HPLC） and chemical analyses confirmed that phenolic compounds were bound to the cell walls of mature cotton fibers. Our findings may suggest a potential for genetic manipulation of cotton fiber properties, which are of central importance to agricultural, cotton processing and textile industries.

Differentially Expressed Genes in Heads and Tails of Angelica Sinensis diels： Focusing on Ferulic Acid Metabolism

Objective： To explore the scientific connotation of the discrepant pharmaceutical activities between the head and tail of Angelica sinensis diels（AS）, an important herb extensively utilized in Chinese medicine, by the approach of transcriptome sequencing. Methods： Ten samples of AS were randomly collected in Min County, Gansu Province of China. Transcriptome sequencing of AS was accomplished in a commercial ILLumina Hi Seq-2000 platform. The transcriptome of each head and tail of AS were fixed in a gene chip, and detected under the procedure of Illumina Hi Seq-2000. Differentially expressed unigenes between the heads and tails of AS were selected by Shanghai Biotechnology Corporation（SBC） online analysis system, based on Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and relevant bioinformatic database. Results： Totally 63,585 unigenes were obtained from AS by high-throughput sequencing platform. Among which 3359 unigenes were identified as differentially expressed unigenes between the heads and tails of AS by SBC analysis system scanning. Of which 15 differentially expressed unigenes participate in the metabolic regulation of phenylpropanoid biosynthesis（PB） pathway and ferulic acid metabolites, in response to the distinguished pharmaceutical actions of the heads and tails of AS. Conclusion： Different content of ferulic acid in the heads and tails of AS is related to the differentially expressed genes, particularly involved in the PB pathway.