Genome-wide investigation of superoxide dismutase (SOD) gene family and their regulatory miRNAs reveal the involvement in abiotic stress and hormone response in tea plant (Camellia sinensis).

Superoxide dismutases (SODs), as a family of metalloenzymes related to the removal of reactive oxygen species (ROS), have not previously been investigated at genome-wide level in tea plant. In this study, 10 CsSOD genes were identified in tea plant genome, including 7 Cu/Zn-SODs (CSDs), 2 Fe-SODs (FSDs) and one Mn-SOD (MSD), and phylogenetically classified in three subgroups, respectively. Physico-chemical characteristic, conserved motifs and potential protein interaction analyses about CsSOD proteins were carried out. Exon-intron structures and codon usage bias about CsSOD genes were also examined. Exon-intron structures analysis revealed that different CsSOD genes contained various number of introns. On the basis of the prediction of regulatory miRNAs of CsSODs, a modification 5' RNA ligase-mediated (RLM)-RACE was performed and validated that csn-miR398a-3p-1 directly cleaves CsCSD4. By prediction of cis-acting elements, the expression patterns of 10 CsSOD genes and their regulatory miRNAs were detected under cold, drought, exogenous methyl jasmonate (MeJA) and gibberellin (GA3) treatments. The results showed that most of CsSODs except for CsFSD2 were induced under cold stress and CsCSDs may play primary roles under drought stress; exogenous GA3 and MeJA could also stimulated/inhibited distinct CsSODs at different stages. In addition, we found that csn-miR398a-3p-1 negatively regulated the expression of CsCSD4 may be a crucial regulatory mechanism under cold stress. This study provides a certain basis for the studies about stress resistance in tea plants, even provide insight into comprehending the classification, evolution, diverse functions and influencing factors of expression patterns for CsSOD genes.

De novo transcriptome and phytochemical analyses reveal differentially expressed genes and characteristic secondary metabolites in the original oolong tea (Camellia sinensis) cultivar 'Tieguanyin' compared with cultivar 'Benshan'.

BACKGROUND: The two original plants of the oolong tea cultivar ('Tieguanyin') are "Wei shuo" 'Tieguanyin'-TGY (Wei) and "Wang shuo" 'Tieguanyin'-TGY (Wang). Another cultivar, 'Benshan' (BS), is similar to TGY in its aroma, taste, and genetic make-up, but it lacks the "Yin Rhyme" flavor. We aimed to identify differences in biochemical characteristics and gene expression among these tea plants. RESULTS: The results of spectrophotometric, high performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS) analyses revealed that TGY (Wei) and TGY (Wang) had deeper purple-colored leaves and higher contents of anthocyanin, catechins, caffeine, and limonene compared with BS. Analyses of transcriptome data revealed 12,420 differentially expressed genes (DEGs) among the cultivars. According to a Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the flavonoid, caffeine, and limonene metabolic pathways were highly enriched. The transcript levels of the genes involved in these three metabolic pathways were not significantly different between TGY (Wei) and TGY (Wang), except for two unigenes encoding IMPDH and SAMS, which are involved in caffeine metabolism. The comparison of TGY vs. BS revealed eight up-regulated genes (PAL, C4H, CHS, F3'H, F3H, DFR, ANS, and ANR) and two down-regulated genes (FLS and CCR) in flavonoid metabolism, four up-regulated genes (AMPD, IMPDH, SAMS, and 5'-Nase) and one down-regulated XDH gene in caffeine metabolism; and two down-regulated genes (ALDH and HIBADH) in limonene degradation. In addition, the expression levels of the transcription factor (TF) PAP1 were significantly higher in TGY than in BS. Therefore, high accumulation of flavonoids, caffeine, and limonene metabolites and the expression patterns of their related genes in TGY might be beneficial for the formation of the "Yin Rhyme" flavor. CONCLUSIONS: Transcriptomic, HPLC, and GC-MS analyses of TGY (Wei), TGY (Wang), and BS indicated that the expression levels of genes related to secondary metabolism and high contents of catechins, anthocyanin, caffeine, and limonene may contribute to the formation of the "Yin Rhyme" flavor in TGY. These findings provide new insights into the relationship between the accumulation of secondary metabolites and sensory quality, and the molecular mechanisms underlying the formation of the unique flavor "Yin Rhyme" in TGY.

[Effect of transcutaneous electrical acupoint stimulation on gastric emptying in patients undergoing surgery].

OBJECTIVE: To observe the effects of transcutaneous electrical acupoint stimulation (TEAS) on gastric emptying in patients undergoing selective surgery based on velocity of gastric emptying by ultrasonography. METHODS: A total of 75 patients with selective operation of subarachnoid block at lower limb in the afternoon were randomly assigned to a TEAS group, a sham group and a control group, 25 patients in each one. All the patients were provided with semi-fluid diet at 8 a.m. The TEAS group was treated with TEAS 5 min after semi-fluid diets at bilateral Zusanli (ST 36) and Neiguan (PC 6) for 30 min, with frequency of 5 Hz and intensity which was 1 mA lower than the tolerance threshold. The sham group patients were stimulated at the same acupoints with current intensity which was 1 mA lower than the sensory threshold. The control group received no treatment. On the day of operation, and ultrasonography was given at time of empty stomach (T0), immediately after the semi-fluid diets (T1), and every 30 min after diets (T2-T6), respectively, to measure the gastric content and emptying time at semire-clining position and right lateral position. RESULTS: The volume of gastric content in the three groups at T3-T6 was significantly less than that at T1 (all P<0.05). The volume of gastric content at T4-T6 at semire-clining position in the TEAS group was significantly less than that in the control group and sham group (all P<0.05). The volume of gastric content at T5-T6 at right lateral position in the TEAS group was significantly less than that in the control group and sham group (all P<0.05). The gastric emptying time in the TEAS group was significantly less than that in the control group and sham group (both P<0.05). CONCLUSION: The gastric emptying velocity could be evaluated by ultrasonography. TEAS could improve the velocity of gastric emptying and reduce the gastric emptying time.