Expression response of chalcone synthase gene to inducing conditions and its effect on flavonoids accumulation in two medicinal species of Anoectochilus

Anoectochilus roxburghii and Anoectochilus formasanus are the major species of genus Anoectochilus used in traditional Chinese medicine for their abundant content of flavonoids and some other medicinal constituents. In recent years, their wild resources are gradually exhausted due to over-collection and ecological deterioration. Artificial cultivation and tissue culture are employed to increase production. In this study, the open reading frame, promoter and genomic sequences of the chalcone synthase (CHS) gene were cloned from these two species according to their transcriptome information, and used for expression analysis in response to the induction of phenylalanine, ultraviolet light and NaCl, and its effect investigation on accumulation of flavonoids. The results showed that the expression of the CHS genes was upregulated in response to these inductions and resulted in increasing accumulation of total flavonoids. However, the increased flavonoids induced by phenylalanine and ultraviolet light were mainly allocated into the anthocyanidin branch of flavonoids biosynthesis. Not only did it improved the medicinal value, but might have inhibitory effect on plant growth because of the increased malondialdehyde accumulation. Under the induction of appropriate concentration of NaCl, the medicinal constituents of flavonoids were increased without inhibition to plant growth.

Expression, Subcellular Localization, and Interactions of CPK Family Genes in Maize

Calcium-dependent protein kinase (CPKs) is a key player in the calcium signaling pathway to decode calcium signals into various physiological responses. cDNA sequences of 9 ZmCPK genes were successfully cloned from all four phylogenetic groups in maize. qRT-PCR analysis showed the expression variation of these selected genes under abscisic acid (ABA) and calcium chloride (CaCl2) treatment. Due to the presence of N-myristoylation/palmitoylation sites, the selected ZmCPK members were localized in a plasma membrane. To clarify whether ZmCPK, a key player in calcium signaling, interacts with key players of ABA, protein phosphatase 2Cs (PP2Cs) and the SNF1-related protein kinase 2s (SnRK2s) and mitogen-activated protein kinase (MAPK) signaling pathways in maize, we examined the interaction between 9 CPKs, 8 PP2Cs, 5 SnRKs, and 20 members of the MPK family in maize by using yeast two-hybrid assay. Our results showed that three ZmCPKs interact with three different members of ZmSnRKs while four ZmCPK members had a positive interaction with 13 members of ZmMPKs in different combinations. These four ZmCPK proteins are from three different groups in maize. These findings of physical interactions between ZmCPKs, ZmSnRKs, and ZmMPKs suggested that these signaling pathways do not only have indirect influence but also have direct crosstalk that may involve the defense mechanism in maize. The present study may improve the understanding of signal transduction in plants.

[Value of intravoxel incoherent motion diffusion weighted imaging in evaluating the microstructure changes in white matter hyperintensities]

Objective: To investigate the value of intravoxel incoherent motion diffusion weighted imaging (IVIM DWI) in evaluating microstructure changes in elderly white matter hyperintensities (WMH) patients and to analyze the correlation between IVIM parameters and severity grading and cognitive scores. Methods: Sixty-two WMH patients in Zhejiang Hospital were collected from December 2014 to March 2018 and underwent conventional magnetic resonance (MR) plain scan and diffusion weighted imaging with different b values. The age was 60-92(74±10) years with 37 males, 25 females. The severity of WMH was assessed by T(2) fluid attenuated inversion recovery (FLAIR) sequence and Fazekas score,which were divided into two subgroups. Slow diffusion coefficient (D), fast diffusion coefficient (D(*)) and perfusion fraction (f) from IVIM parameters of double exponential model were compared between regions of WMH (deep WMH (DWMH) and periventricular WMH (PWMH)) and surrounding normal white matter (NWM).The Shapiro-Wilk test was used for normality tests, Kruskal-Wallis tests and Dwass-Steel-Critchlow-Fligner (DSCF) procedure were used for the comparison among these parameters. Furthermore, Wilcoxon two-sample test was used for the comparisons between different severity. Pearson correlation analysis was performed to determine whether these D, D(*), f values were correlated with the mini mental state examination (MMSE) scores. Results: D(D)WMH (0.83(0.72,0.99)×10(-3) mm(2)/s), D(PWMH)((1.13±0.25)×10(-3) mm(2)/s) were significantly higher than D(NWM) ((0.71±0.05)×10(-3) mm(2)/s)(P<0.01). f (DWMH) ((8.94%(7.46%,11.67%)), f (PWMH)(8.34%(6.73%,9.96%)) were significantly higher than f (NWM)(6.71%±1.72%)(P<0.01).D in DWMH were significantly lower than that in PWMH(P<0.01), there's no statistically difference between other groups. D in severe WMH (both DWMH and PWMH) were significantly higher than that in mild WMH (P=0.000 1, P=0.04). Only f in PWMH were positively associated with the MMSE scores (r=0.326 5,P<0.05). Conclusions: IVIM DWI can noninvasively assess the variation of microstructure diffusion and perfusion in WMH in one sequence,which may objectively reflect the severity of these lesions. This method has important clinical significance for better assessment and management of this disease.

[The BES1/BZR1 transcription factors regulate growth, development and stress resistance in plants]

Brassinosteroid (BR) is a class of plant-specific steroidal hormone and plays vital roles in plant growth, developmental and stress response. As the core component of BR signaling, the BES1/BZR1 transcription factors are activated by the BR signal, bind to the E-box (CANNTG) or BRRE element (CGTGT/CG) enriched in the promoter of downstream target genes and regulate their expression. Besides BR signal transduction, BES1/BZR1s are also involved in other signaling pathways such as abscisic acid, gibberellin and light to co-regulate plant growth and development. Recently, BES1/BZR1s were found to be related to stress resistance. In this review, we summarize recent advances of molecular mechanism of the BES1/BZR1 transcription factors regulating plant growth, development and stress resistance through signal transduction to provide a reference for related researches.

Overexpression of a phospholipase Dα gene from Ammopiptanthus nanus enhances salt tolerance of phospholipase Dα1-deficient Arabidopsis mutant

A phospholipase Dα gene ( AnPLDα ) was cloned from xerophytic desert plant Ammopiptanthus nanus and its overexpression enhanced salt tolerance of a PLDα1 deficient Arabidopsis mutant. Phospholipase Dα (PLDα) hydrolyzes phosphatidylcholine to produce phosphatidic acid, and plays crucial role in plant tolerance to abiotic stress. In this study, a phospholipase Dα gene (AnPLDα) was cloned from xerophyte Ammopiptanthus nanus by the methods of homologous cloning and rapid amplification of cDNA ends, and evaluated for its function in stress tolerance. The full-length cDNA was 2832 bp long, containing an open reading frame of 2427 bp that encodes 808 amino acids. The putative protein was predicted to be localized to the cytoplasm and this was confirmed by transient expression of a fluorescent fusion protein. The endogenous expression of the AnPLDα gene was induced by high salt, dehydration, cold and abscisic acid. The heterologous expression of the AnPLDα gene improved salt tolerance of an Arabidopsis pldα1 knocked out mutant, and positively regulated the expression of the AtABI, AtNCED, AtRD29A, AtRD29B and AtADH genes. Therefore, the AnPLDα gene was concluded to be involved in response to abiotic stress. The AnPLDα gene is a hopeful candidate for transgenic application to improve stress tolerance of commercial crops.

Cloning and functional validation of molybdenum cofactor sulfurase gene from Ammopiptanthus nanus

The molybdenum cofactor sulfurase gene ( AnMCSU ) was cloned from xerophytic desert plant Ammopiptanthus nanus and validated for its function of tolerance toward abiotic stresses by heterologous expression in Arabidopsis thaliana. Molybdenum cofactor sulfurase participates in catalyzing biosynthesis of abscisic acid, which plays a crucial role in the response of plants to abiotic stresses. In this study, we cloned molybdenum cofactor sulfurase gene (AnMCSU) from a super-xerophytic desert plant, Ammopiptanthus nanus, by using rapid amplification of cDNA ends method. This gene has a total length of 2544 bp, with a 5'- and a 3'-untranslated region of 167 and 88 bp, and an open reading frame of 2289 bp, which encodes an 84.85 kDa protein of 762 amino acids. The putative amino acid sequence shares high homology and conserved amino acid residues crucial for the function of molybdenum cofactor sulfurases with other leguminous species. The encoded protein of the AnMCSU gene was located in the cytoplasm by transient expression in Nicotiana benthamiana. The result of real-time quantitative PCR showed that the expression of the AnMCSU gene was induced by heat, dehydration, high salt stresses, and ABA induction, and inhibited by cold stress. The heterologous expression of the AnMCSU gene significantly enhanced the tolerance of Arabidopsis thaliana to high salt, cold, osmotic stresses, and abscisic acid induction. All these results suggest that the AnMCSU gene might play a crucial role in the adaptation of A. nanus to abiotic stress and has potential to be applied to transgenic improvement of commercial crops.