Metabolomic and transcriptomic analyses of peach leaves and fruits in response to pruning.

BACKGROUND: Pruning is an important cultivation management option that has important effects on peach yield and quality. However, the effects of pruning on the overall genetic and metabolic changes in peach leaves and fruits are poorly understood. RESULTS: The transcriptomic and metabolomic profiles of leaves and fruits from trees subjected to pruning and unpruning treatments were measured. A total of 20,633 genes and 622 metabolites were detected. Compared with those in the control, 1,127 differentially expressed genes (DEGs) and 77 differentially expressed metabolites (DEMs) were identified in leaves from pruned and unpruned trees (pdLvsupdL), whereas 423 DEGs and 29 DEMs were identified in fruits from the pairwise comparison pdFvsupdF. The content of three auxin analogues was upregulated in the leaves of pruned trees, the content of all flavonoids detected in the leaves decreased, and the expression of almost all genes involved in the flavonoid biosynthesis pathway decreased. The phenolic acid and amino acid metabolites detected in fruits from pruned trees were downregulated, and all terpenoids were upregulated. The correlation analysis revealed that DEGs and DEMs in leaves were enriched in tryptophan metabolism, auxin signal transduction, and flavonoid biosynthesis. DEGs and DEMs in fruits were enriched in flavonoid and phenylpropanoid biosynthesis, as well as L-glutamic acid biosynthesis. CONCLUSIONS: Pruning has different effects on the leaves and fruits of peach trees, affecting mainly the secondary metabolism and hormone signalling pathways in leaves and amino acid biosynthesis in fruits.

PpSAUR5 promotes plant growth by regulating lignin and hormone pathways.

Introduction: Peach (Prunus persica) has a high nutritional and economic value. However, its overgrowth can lead to yield loss. Regulating the growth of peach trees is challenging. The small auxin-up RNA (SAUR) gene family is the largest family of auxin-responsive genes, which play important roles in plant growth and development. However, members of this gene family are rarely reported in peach. Methods: In this study, we measured leaf area, chlorophyll and lignin content to detect the role of PpSAUR5 on growth through transgenic Arabidopsis. Results: PpSAUR5 responds to auxin and gibberellin, promoting and inhibiting the synthesis of gibberellin and auxin, respectively. The heterologous transformation of PpSAUR5 in Arabidopsis led to enhanced growth of leaves and siliques, lightening of leaf color, decrease in chlorophyll content, increase in lignin content, abnormalities in the floral organs, and distortion of the inflorescence axis. Transcriptome data analysis of PpSAUR5 overexpression and wild-type lines revealed 854 differentially expressed genes (DEGs). GO and KEGG analyses showed that the DEGs were primarily involved in biological processes, such as cellular processes, metabolic processes, response to stimuli, and catalytic activity. These genes were mainly enriched in pathways, such as phenylalanine biosynthesis, phytohormone signaling, and MAPK signaling. Discussion: In summary, these results suggested that PpSAUR5 might regulate tree vigor by modulating the synthesis of auxin and gibberellin. Future studies can use PpSAUR5 as a candidate gene to elucidate the potential regulatory mechanisms underlying peach tree vigor.

MicroRNA-136 Promotes Vascular Muscle Cell Proliferation Through the ERK1/2 Pathway by Targeting PPP2R2A in Atherosclerosis.

Aberrant proliferation of vascular smooth muscle cells [VSMCs] is implicated in the pathogenesis of vascular pathologies such as atherosclerosis and restenosis. Accumulating evidences have revealed that microRNAs are involved in cell proliferation in various pathological conditions. In the present study, we showed that miR-136 was up regulated in human coronary atherosclerotic plaques when compared with normal coronary artery tissues. Moreover, miR-136 levels were up regulated in proliferative vascular smooth muscle cells induced by platelet-derived growth factor [PDGF] or serum. In cultured VSMCs, over expression of miR-136 stimulated cell proliferation. PPP2R2A was proved to be the direct target gene of miR-136 and knockdown of PPP2R2A had a proliferative effect on VSMCs. miR-136-induced PPP2R2A down-regulation was accompanied by increased expression of ERK1/2 phosphorylation. Inhibition of ERK1/2 abolished the effect of miR-136 and knockdown of PPP2R2A on VSMCs proliferation. In summary, aberrant miR-136 up regulation in atherosclerosis contributes to abnormal VSMC proliferation through suppressing the ERK1/2 pathway by targeting PPP2R2A. Our study also suggested that specific modulation of miR-136 in human VSMCs may provide a potential approach for the treatment of atherosclerosis.

[Changes of blood viscosity and erythrocyte rheology in acute hypoxic hypoxia mices].

OBJECTIVE: To observe the changes of blood viscosity and erythrocyte rheology in mice after acute hypoxic hypoxia (AHH). METHODS: Thirty-two Kui-ming mice were randomly divided into control group, AHH group (duplicating AHH model, and divided into 5 min, 8 min, 11 min subgroups), the blood sample was taken out from heart after neck dislocation at corresponding times, for detecting the blood viscosity and erythrocyte rheology indices. RESULTS: Compared with control group, the whole blood viscosity at different shears, whole blood reduced viscosity, whole blood relative viscosity were lower and the erythrocytes aggregation index was higher in AHH 5 min group; the electrophoresis time was longer and the electrophoresis length, migration of erythrocyte were lower in AHH 8 min and AHH 11 min groups. The whole blood reduced viscosity, whole blood relative viscosity, erythrocytes aggregation index in AHH 8 min group were higher, and the erythrocyte deformability index was lower significantly than that of AHH 5 min group, respectively. CONCLUSION: These data suggested that the AHH could induce the blood viscosity and electrophoresis ability.

[Effect of mesenteric lymph obtained during shock on pump activity and oxygen free radical on erythrocyte membrane of rat].

OBJECTIVE: To observe the effects of mesenteric lymph drainage and transfusion on pump activity and oxygen free radical of erythrocyte membrane of rats following hemorrhagic shock or normal, respectively. METHODS: Twenty-four male Wistar rats were randomly divided into sham-shock group, shock group, shock mesenteric lymph drainage group (drainage group) and shock mesenteric lymph transfusion group (transfusion group) by randomization, with 6 rats in each group. Model of hemorrhagic shock was reproduced both in shock group and drainage group after anesthesia and operation, mesenteric lymph was drained 1 hour after shock in drainage group. Sham-shock group only received anesthesia and laparotomy, and the obtained mesenteric lymph was transfused in transfusion group. Blood was obtained from abdominal aorta, and red cell membrane suspension was prepared after 3 hours of shock or corresponding time, then the indices of erythrocyte membrane pump activity and oxygen free radical were determined. RESULTS: Compared with sham-shock group, the activity of Na(+)-K(+)-ATPase (µmol×mg(-1)×h(-1)), Ca(2+)-ATPase (µmol×mg(-1) ×h(-1) ) and superoxide dismutase (SOD) (NU/mg)of red cell membrane were decreased markedly (Na(+)-K(+)-ATPase: 0.039±0.011 vs. 0.068±0.010; Ca(2+)-ATPase: 0.035±0.016 vs. 0.087±0.015; SOD: 0.785±0.289 vs. 1.202±0.328, P<0.05 or P<0.01), and the content of malondialdehyde (MDA, nmol/mg) was increased markedly in shock group (1.914±0.225 vs. 0.913±0.138, P<0.01). Compared with shock group, the activity of Na(+)-K(+)-ATPase (0.056±0.009), Ca(2+)-ATPase (0.079±0.025) and SOD (1.220±0.380) of red cell membrane were increased in drainage group, and the level of MDA (1.214±0.127) was decreased markedly (P<0.05 or P<0.01). Compared with sham-shock group, the activity of Na(+)-K(+)-ATPase (0.050±0.013), Ca(2+)-ATPase (0.056±0.023) of red cell membrane in transfusion group were significantly lower (both P<0.05), the content of MDA (1.456±0.270) was significantly higher (P<0.01), respectively, the activity of SOD (0.862±0.288) showed a lowering trend, but there was no statistical significance (P>0.05). CONCLUSION: Mesenteric lymph return is a key factor in decreasing pump activity while aggravating free radical damage injury of erythrocyte membrane.