Transcriptomic analysis of Verbena bonariensis roots in response to cadmium stress.

BACKGROUND: Cadmium (Cd) is a serious heavy metal (HM) soil pollutant. To alleviate or even eliminate HM pollution in soil, environmental-friendly methods are applied. One is that special plants are cultivated to absorb the HM in the contaminated soil. As an excellent economical plant with ornamental value and sound adaptability, V. bonariensis could be adapted to this very situation. In our study, the Cd tolerance in V. bonariensis was analyzed as well as an overall analysis of transcriptome. RESULTS: In this study, the tolerance of V. bonariensis to Cd stress was investigated in four aspects: germination, development, physiological changes, and molecular alterations. The results showed that as a non-hyperaccumulator, V. bonariensis did possess the Cd tolerance and the capability to concentration Cd. Under Cd stress, all 237, 866 transcripts and 191, 370 unigenes were constructed in the transcriptome data of V. bonariensis roots. The enrichment analysis of gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway revealed that differentially expressed genes (DEGs) under Cd stress were predominately related to cell structure, reactive oxygen species (ROS) scavenging system, chelating reaction and secondary metabolites, transpiration and photosynthesis. DEGs encoding lignin synthesis, chalcone synthase (CHS) and anthocyanidin synthase (ANS) were prominent in V. bonariensis under Cd stress. The expression patterns of 10 DEGs, validated by quantitative real-time polymerase chain reaction (qRT-PCR), were in highly accordance with the RNA-Sequence (RNA-Seq) results. The novel strategies brought by our study was not only benefit for further studies on the tolerance of Cd and functional genomics in V. bonariensis, but also for the improvement molecular breeding and phytoremediation.

[Effects of exogenous AsA and GSH on the growth of Dianthus chinensis seedlings exposed to Cd].

A pot experiment was carried out under greenhouse condition to investigate the effects of different concentrations (0, 20, 40, 60, 80 and 100 mg x L(-1)) of exogenous AsA, GSH on Dianthus chinensis seedlings which were stressed by 50 mg x kg(-1) Cd in the soil. The results indicated that 50 mg x kg(-1) of Cd significantly inhibited the growth of D. chinensis seedlings. An appropriate concentration of exogenous AsA significantly improved the biomass, plant height, tiller number, GAT and APX activities, and AsA and GSH contents. However, with the increase of exogenous AsA concentration, the ameliorating effect decreased and prooxidant effect occurred. Exogenous GSH could replenish the non-enzymatic antioxidants of D. chinensis seedlings, but the changes of antioxidant enzyme activities were relatively slight. The main mechanisms of GSH to alleviate Cd toxicity might be promoting root PCs synthesis, thereby reducing the Cd concentration in the seedlings. Both 35-45 mg x L(-1) exogenous AsA and 55-65 mg x L(-1) exogenous GSH could alleviate the Cd toxicity on D. chinensis seedlings, and the former was superior to the latter.

Cloning and characterization of a novel vacuolar Na+/H+ antiporter gene (Dgnhx1) from chrysanthemum.

Plant vacuolar Na(+)/H(+) antiporter genes play significant roles in salt tolerance. However, the roles of the chrysanthemum vacuolar Na(+)/H(+) antiporter genes in salt stress response remain obscure. In this study, we isolated and characterized a novel vacuolar Na(+)/H(+) antiporter gene DgNHX1 from chrysanthemum. The DgNHX1 sequence contained 1920 bp with a complete open reading frame of 1533 bp encoding a putative protein of 510 amino acids with a predicted protein molecular weight of 56.3 kDa. DgNHX1 was predicted containing nine transmembrane domains. Its expression in the chrysanthemum was up-regulated by salt stress, but not by abscisic acid (ABA). To assess roles of DgNHX1 in plant salt stress responses, we performed gain-of-function experiment. The DgNHX1-overexpression tobacco plants showed significant salt tolerance than the wild type (WT). The transgenic lines exhibited more accumulation of Na(+) and K(+) under salt stress. These findings suggest that DgNHX1 plays a positive regulatory role in salt stress response.

Overexpression of a novel chrysanthemum Cys2/His2-type zinc finger protein gene DgZFP3 confers drought tolerance in tobacco.

A drought stress-responsive Cys2/His2-type zinc finger protein gene DgZFP3 was previously isolated (Liu et al., Afr J Biotechnol 11:7781-7788, 2012b) from chrysanthemum. To assess roles of DgZFP3 in plant drought stress responses, we performed gain-of-function experiment. The DgZFP3-overexpression tobacco plants showed significant drought tolerance over the wild type (WT). The transgenic lines exhibited less accumulation of H2O2 under drought stress, more accumulation of proline and greater activities of peroxidase (POD) and superoxide dismutase than the WT under both control conditions and drought stress. In addition, there was greater up-regulation of the ROS-related enzyme genes (NtSOD and NtPOD) and stress-related genes (NtLEA5 and NtDREB) in transgenic lines under normal or drought conditons. Thus DgZFP3 probably plays a positive regulatory role in drought stress response and has the potential to be utilized in transgenic breeding to improve drought stress tolerance in plants.

Overexpression of a chrysanthemum transcription factor gene, DgWRKY3, in tobacco enhances tolerance to salt stress.

WRKY transcription factor genes (TFs) play important roles in response to various abiotic stresses. However, the roles of the chrysanthemum WRKY genes in abiotic stress response remain obscure. In this study, we functionally characterized a novel WRKY gene, DgWRKY3, from chrysanthemum (Dendranthema grandiflorum). Its expression in the chrysanthemum was up-regulated by salinity or dehydration stress, but not by abscisic acid (ABA). The DgWRKY3-overexpression tobacco plants increase salt tolerance compared with wild-type (WT) tobacco plants. The increased levels of proline were observed in transgenic plants compared to WT plants under salt stress. In addition, the DgWRKY3 transgenic plants reduced accumulation of malondialdehyde (MDA) and hydrogen peroxide (H2O2) compared with WT plants, accompanied by higher activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and the greater accumulation of antioxidants including ascorbate (AsA) and glutathione (GSH) under salt stress. Moreover, the DgWRKY3 transgenic plants enhanced the expression of stress-related genes involved in osmotic adjustment and membrane protection (NtP5CS, NtLEA5, and NtERD10D) and oxidative stress response (NtSOD, NtPOD, NtCAT, and NtAPX) under salt stress. However, no significant difference in the expression of stress-related genes (NtP5CS, NtLEA5, NtERD10D, NtSOD, NtPOD, NtCAT, and NtAPX) was found between the DgWRKY3-overexpression and WT tobacco plants under normal conditions, despite the fact that the constitutive promoter was used to drive DgWRKY3. These findings suggest that DgWRKY3 functions as a positive regulator to mediate tolerance of plants to salt stress.

Overexpression of a novel chrysanthemum NAC transcription factor gene enhances salt tolerance in tobacco.

The plant-specific NAC (for NAM, ATAF1, 2 and CUC2) transcription factors (TFs) have been implicated in different cellular processes involved in stress responses such as cold, high salinity or drought as well as abscisic acid (ABA) signalling. However, the roles of the chrysanthemum NAC TF genes in plant stress responses are still unclear. A full-length cDNA designated DgNAC1, containing a highly conserved N-terminal DNA-binding NAC domain, has been isolated from chrysanthemum by RACE (rapid amplification of cDNA ends). It encodes a protein of 284 amino acids residues (=~32.9 kDa) and theoretical pI of 7.13. The transcript of DgNAC1 was enriched in roots and flowers than in stems and leaves of the adult chrysanthemum plants. The gene expression was strongly induced by ABA, NaCl, drought and cold treatment in the seedlings. Subcellular localization revealed that DgNAC1:GFP fusion protein was preferentially distributed to nucleus. To assess whether DgNAC1 is a practically useful target gene for improving the stress tolerance of chrysanthemum, we ectopically over-expressed the full-length DgNAC1 cDNA in tobacco and found that the 35S:DgNAC1 transgenic tobacco exhibited a markedly increased tolerance to salt. Despite this increased salt stress tolerance, the transgenic tobacco showed no detectable phenotype defects under normal growth conditions. These results proposed that DgNAC1 is appropriate for application in genetic engineering strategies aimed at improving salt stress tolerance in chrysanthemum.

[Observation on effects of Zhiling Capsule in treating 400 patients with various types of cancer in mid-ad-vanced stage].

OBJECTIVE: To observe the efficacy of Zhiling Capsule (ZLC) in improving symptoms and quality of life (QOL) in patients with various types of cancer in mid-advanced stage. METHODS: A multi-centre randomized and controlled trial was conducted. Four hundred patients with mid-advanced cancer were assigned to two groups: the treatment group (300 cases) treated with ZLC and the control group (100 cases) with Pingxiao Capsule (PXC), both were given orally for two weeks. Clinical symptoms, QOL, weight and adverse reactions were observed before and after treatment. RESULTS: Improving rate of symptom, increasing rates of QOL and weight in the treatment group were all higher than those in the control group (P<0.05); and no obvious adverse reaction was observed in the two groups. CONCLUSION: ZLC could alleviate the qi-yin deficiency syndrome and pain syndrome and improve QOL in patients with various types of cancer in mid-advanced stage.

[Observation on the effect of zhiling capsule in treating patients with lung cancer of middle/advanced stage].

OBJECTIVE: To observe the effect and safety of Zhiling Capsule (ZC) in treating lung cancer of middle/advanced stage. METHODS: With the multi-center, randomized, double-blinded and parallel controlled method, the patients were divided into 4 groups, the 104 patients in the group A were treated with the whole recipe of ZC, the 52 in the group B with the disassembled recipe 1 (Western medicines) of ZC, the 46 in the group C with the disassembled recipe 2 (Chinese medicines) of ZC, and the 48 in the control group with Pingxiao Capsule, all the drugs were administered orally for 2 weeks. The changes of syndrome of qi-yin deficiency, symptoms, quality of life (QOL), body weight and adverse reactions occurred in patients were observed. RESULTS: The effective rate in alleviating syndrome in the groups A-D was 91.3%, 80.8%, 37.0% and 14.6% respectively; in remitting stuffiness and chest pain 86.9% , 60.5%, 20.0% and 10.0%; in improving appetite was 80.4%, 47.9%, 23.7% and 10.3%. QOL in the groups A-C was significantly elevated after treatment (P < 0.05 or P < 0.01), the improvement of group A was superior to that of other treatments (P < 0.01). Body weight in the group A was significantly increased and superior to that of others (P < 0.05). The whole recipe of ZC showed the therapeutic effect superior to that of the other treatments (P < 0.05). No obvious adverse reaction was found in all the 4 groups. CONCLUSION: ZC can improve the symptoms and QOL in patients with lung cancer of middle/advanced stage.