Transcriptome and metabolome analyses reveal molecular mechanisms of anthocyanin-related leaf color variation in poplar (Populus deltoides) cultivars.

Introduction: Colored-leaf plants are increasingly popular for their aesthetic, ecological, and social value, which are important materials for research on the regulation of plant pigments. However, anthocyanin components and the molecular mechanisms of anthocyanin biosynthesis in colored-leaf poplar remain unclear. Consequently, an integrative analysis of transcriptome and metabolome is performed to identify the key metabolic pathways and key genes, which could contribute to the molecular mechanism of anthocyanin biosynthesis in the colored-leaf cultivars poplar. Methods: In this study, integrated metabolite and transcriptome analysis was performed to explore the anthocyanin composition and the specific regulatory network of anthocyanin biosynthesis in the purple leaves of the cultivars 'Quanhong' (QHP) and 'Zhongshanyuan' (ZSY). Correlation analysis between RNA-seq data and metabolite profiles were also performed to explore the candidate genes associated with anthocyanin biosynthesis. R2R3-MYB and bHLH TFs with differential expression levels were used to perform a correlation analysis with differentially accumulated anthocyanins. Results and discussion: A total of 39 anthocyanin compounds were detected by LC-MS/MS analysis. Twelve cyanidins, seven pelargonidins, five delphinidins, and five procyanidins were identified as the major anthocyanin compounds, which were differentially accumulated in purple leaves of QHP and ZSY. The major genes associated with anthocyanin biosynthesis, including structural genes and transcription factors, were differentially expressed in purple leaves of QHP and ZSY through RNA-sequencing (RNA-seq) data analysis, which was consistent with quantitative real-time PCR analysis results. Correlation analysis between RNA-seq data and metabolite profiles showed that the expression patterns of certain differentially expressed genes in the anthocyanin biosynthesis pathway were strongly correlated with the differential accumulation of anthocyanins. One R2R3-MYB subfamily member in the SG5 subgroup, Podel.04G021100, showed a similar expression pattern to some structural genes. This gene was strongly correlated with 16 anthocyanin compounds, indicating that Podel.04G021100 might be involved in the regulation of anthocyanin biosynthesis. These results contribute to a systematic and comprehensive understanding of anthocyanin accumulation and to the molecular mechanisms of anthocyanin biosynthesis in QHP and ZSY.

Pancreatic necrosis and severity are independent risk factors for pancreatic endocrine insufficiency after acute pancreatitis: A long-term follow-up study.

BACKGROUND: Pancreatic endocrine insufficiency after acute pancreatitis (AP) has drawn increasing attention in recent years. AIM: To assess the impact of risk factors on the development of pancreatic endocrine insufficiency after AP. METHODS: This retrospective observational long-term follow-up study was conducted in a tertiary hospital. Endocrine function was evaluated by the oral glucose tolerance test. The data, including age, sex, body mass index, APACHE II score, history of smoking and drinking, organ failure, pancreatic necrosis, debridement of necrosis (minimally invasive and/or open surgery), and time interval, were collected from the record database. RESULTS: A total of 361 patients were included in the study from January 1, 2012 to December 30, 2018. A total of 150 (41.6%) patients were diagnosed with dysglycemia (including diabetes mellitus and impaired glucose tolerance), while 211 (58.4%) patients had normal endocrine function. The time intervals (mo) of the above two groups were 18.73 ± 19.10 mo and 31.53 ± 27.27 mo, respectively (P = 0.001). The morbidity rates of pancreatic endocrine insufficiency were 46.7%, 28.0%, and 25.3%, respectively, in the groups with different follow-up times. The risk factors for pancreatic endocrine insufficiency after AP were severity (odds ratio [OR] = 3.489; 95% confidence interval [CI]: 1.501-8.111; P = 0.004) and pancreatic necrosis (OR = 4.152; 95%CI: 2.580-6.684; P = 0.001). CONCLUSION: Pancreatic necrosis and severity are independent risk factors for pancreatic endocrine insufficiency after AP. The area of pancreatic necrosis can affect pancreatic endocrine function.

Ionic effects of Na+ and Cl- on photosynthesis in Glycine max seedlings under isoosmotic salt stress.

Ion-specific stress effects of Na(+) and Cl(-) on photosynthesis of seedlings of two soybean (Glycine max) cultivars (the salt-tolerant 'Lee68' and the salt-sensitive 'N23674') were studied and compared under isoosmotic (-0.53 MPa) solutions [PEG-6000, NaCl, Na(+) (without Cl(-)) and Cl(-) (without Na(+))] for 6 d. The results showed that the chlorophyll contents and the ribulose bisphosphate carboxylase/oxygenase (Rubisco) activities of seedlings of both cultivars were inhibited to a less degree by PEG-6000 than by NaCl, Na(+) (without Cl(-)) or Cl(-) (without Na(+)) solutions. The maximum photochemical efficiency of photosystem II (PSII) (F(v)/F(m)), electron transfer rate (ETR) and effective quantum yield of PSII photochemistry (F(v)'/F(m)') were lowered significantly by PEG-6000 treatment for 2 d and 6 d. But when treated with the three isoosmotic salt stresses, most of the above three indexes significantly declined. Leaf stomatal conductance (G(s)) and net photosynthetic rate (P(n)) in both cultivars were significantly decreased under the four isoosmotic treatments, and much more drops were observed in the three salt stresses, but the intercellular CO(2) concentration (C(i)) decreased by PEG-6000 treatment and increased by the three salt stresses. Higher decreases including chlorophyll content, Rubisco activity, F(v)/F(m), ETR, F(v)'/F(m)', P(n) and G(s), and higher contents of Cl(-) as well as the content of Cl(-) plus Na(+) in chloroplasts were all observed under Cl(-) (without Na(+)) treatment than those under Na(+) (without Cl(-)) treatment, especially for the salt-sensitive cultivar 'N23674'. The results indicate that, among the adverse effects of NaCl stress on photosynthesis of G. max seedlings, the ionic toxicity was stronger than osmotic stress, and the toxicity of Cl(-) was more severe than that of Na(+).

[Relationship between chloride tolerance and polyamine accumulation in Glycine max, Glycine soja, and their hybrid seedlings].

The seedlings of the F4 hybrid strain 'JB185' selected for salt tolerance generation by generation, their parents Glycine max cv. Jackson and Glycine soja population 'BB52' were treated with different NaCl concentrations and iso-osmotic (-0.53 MPa) PEG-6000, NaCl, Na+ (without Cl-) and Cl- (without Na+) solutions for 6 d. The results showed that: (1) The relative electrolyte leakage and malondialdehyde (MDA) content in leaves of the above three soybean seedlings showed an increase trend when the NaCl concentration was elevated, but chlorophyll contents decreased except the significant increase in 'BB52' and 'JB185' under NaCl 50 mmol/L stress. The change in 'JB185' was between its parents. (2) Under different iso-osmotic stresses, the relative electrolyte leakage and MDA contents in leaves of three soybean seedlings also increased mostly, the changes in 'BB52' and 'JB185' under Na+ (without Cl-) stress were more than those under Cl- (without Na+) stress. The free and bound Put, Spd and Spm contents in leaves all increased when compared with the control, the ratios of free (Spd+Spm)/Put and total bound polyamines in 'BB52' and 'JB185' seedlings under Na+ (without Cl-) treatment were the lowest one among three iso-osmotic salt stresses. The results indicate that the F4 hybrid strain 'JB185' is more sensitive to Na+ than Cl- as its wild parent 'BB52' population.

Effects of salinity on activities of H+ -ATPase, H+ -PPase and membrane lipid composition in plasma membrane and tonoplast vesicles isolated from soybean (Glycine max L.) seedlings.

The effects of NaCl stress on the H+ -ATPase, H+ -PPase activity and lipid composition of plasma membrane (PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars (Glycine max L.) differing in salt tolerance (Wenfeng7, salt-tolerant; Union, salt-sensitive) were investigated. When Wenfeng7 was treated with 0.3% (W/V) NaCl for 3 d, the H+ -ATPase activities in PM and TP from roots and leaves exhibited a reduction and an enhancement, respectively. The H+ -PPase activity in TP from roots also increased. Similar effects were not observed in roots of Union. In addition, the increases of phospholipid content and ratios of phospholipid to galactolipid in PM and TP from roots and leaves of Wenfeng7 may also change membrane permeability and hence affect salt tolerance.

A putative soybean GmsSOS1 confers enhanced salt tolerance to transgenic Arabidopsis sos1-1 mutant.

The cDNA of GmsSOS1, a putative plasma membrane Na(+)/H(+) antiporter gene isolated from Glycine max, Glycine soja, and their hybrid, was constructed into plant expression vector pCAMBIA 1300 and then transformed with Agrobacterium tumefaciens under the control of CaMV 35S promoter to Arabidopsis thaliana wild-type (WT) and mutant (atsos1-1) plants. By hygromycin resistance detection and PCR analysis, transgenic plants (WT35S:GmsSOS1 and atsos1-1 35S:GmsSOS1) were obtained. Seed germination, seedling growth, and Na(+) contents in roots and shoots were analytically compared among WT, atsos1-1 mutant, and their transgenic lines under salt stress. The results showed that when GmsSOS1 was integrated into the genome of A. thaliana, the inhibitions of salt stress on seed germination and seedling growth were all significantly improved, and enhanced salt tolerance was displayed, which may be attributed to the decrease of Na(+) absorption in roots and transportation in shoots of the transgenic lines, especially for that of atsos1-1 mutant.

Tonoplast H+-ATPase activity in barley roots is regulated by ATP and pyrophosphate contents under NaCl stress.

The changes in ATP and PPi contents in roots under NaCl stress, and the effect of PPi on tonoplast H(+)-ATPase activity were studied with two barley cultivars differing in salt tolerance. The results showed that tonoplast H(+)-ATPase activity in salt-tolerant barley cultivar "Tanyin 2" roots increased obviously under NaCl 200 mmol/L (containing half-strength Hoagland solution) for 2 d, and decreased gradually. Tonoplast H(+)-PPase activity always decreased under NaCl stress. For salt-sensitive barley cultivar "Kepin 7", both tonoplast H(+)-ATPase and H(+)-PPase activities decreased during NaCl stress, as compared with control(grown in half-strength Hoagland solution), ATP content of "Tanyin 2" roots increased under NaCl stress for 2 d, and decreased on 4 d after NaCl stress, as compared with control. In "Kepin 7" roots, ATP accumulation was inhibited during NaCl stress. Pyrophosphate (PPi) content increased slightly both in "Tanyin 2" and "Kepin 7" roots under NaCl stress. Tonoplast H(+)-ATPase activity was inhibited competitively by PPi. These results indicated that the increase in rate of ATP accumulation might be essential for the stimulation of tonoplast H(+)-ATPase activity induced by NaCl. The decrease in ATP content and the inhibition of PPi might result in the decrease of tonoplast H(+)-ATPase activity in barley roots under NaCl stress.