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Zhang B.-L.,Zhejiang University | Shang S.-H.,Guizhou Tobacco Science Institute | Zhang H.-T.,Zhejiang University | Jabeen Z.,Zhejiang University | Zhang G.-P.,Zhejiang University
Environmental Toxicology and Chemistry | Year: 2013

The effect of sodium chloride (NaCl) on cadmium (Cd) uptake, translocation, and oxidative stress was investigated using 2 tobacco cultivars differing in Cd tolerance. The growth inhibition of the tobacco plants exposed to Cd toxicity was in part alleviated by moderate addition of NaCl in the culture solution. Cadmium concentration of shoots and roots in the 2 cultivars increased with increasing Cd levels in the solution and decreased with the addition of NaCl. The addition of NaCl could alleviate the oxidative stress caused by Cd toxicity, as reflected by reduced production of malondialdehyde and recovered or enhanced activities of antioxidative enzymes catalase and glutathione peroxidase. The results also showed that the enhancement of antioxidative enzyme activity by NaCl for the tobacco plants exposed to Cd stress is related to induced Ca signaling. © 2013 SETAC.


Chen X.,Guizhou Tobacco Science Institute | Cai L.,Guizhou Tobacco Science Institute | Zheng S.,Guizhou Tobacco Science Institute
Tobacco Science and Technology | Year: 2013

In order to breed tobacco plant without axillary bud growing after topping, the fragment DNA sequence of tobacco axillary bud related gene (named as TLR gene) was cloned from flue-cured tobacco cv. K326 basing on homology gene cloning method, and its sequence was analyzed with BLAST search and Genebank homology comparison, it was found that that gene had high identity with LS gene of Lycopersicum esculentum, and had certain identity with MOC gene of Oryza sativa and LAS gene of Arabidopsis thaliana. The reverse and forward fragments (640 bp) in the reading frame of TLR gene were configured into right and left sides of intron in intermediated RNAi vector pHANNIBAL, respectively. After being cut by NotI'a fragment of about 4300 bp was recovered and inserted into a binary plasmid pART27, plant expression plasmid pHANNIBAL-TLR-PART27 with inverted repeated sequence containing TLR was successfully constructed. The pHANNIBAL-TLR-PART27 was introduced into Agrobacterium tumefaciens LBA4404, then transformed cells in tobacco leaf, but no transgenic plant was obtained, it was suspected that the expression of TLR gene was restrained.


Wang H.,Guizhou Tobacco Science Institute | Li W.,Guizhou Institute of Plant Protection | Chen Q.,Guizhou Tobacco Science Institute | Huang Y.,Yangtze University | And 6 more authors.
Phytopathology | Year: 2012

A simple, rapid, small-scale microbioassay for infection of tobacco seedlings by Phytophthora parasitica var. nicotianae was developed here. This assay uses tobacco seedlings cultivated in petri dishes for a standardized method for quantitation of initial zoospore inocula and highthroughput screening of antagonistic bacteria. Zoospore inocula between 102 to 105 spores per petri dish were inoculated on 14-day-old tobacco seedlings for the susceptibility test. The optimum inocula was established to be ten thousand zoospores. One hundred and fifty pure culture bacteria with different pigments, growth rates, and morphologies were isolated from rhizosphere soil of tobacco and screened for protective ability against tobacco black shank. Fifteen bacteria presented high activity against P. parasitica on tobacco seedlings. They were identified by Biolog GEN III MicroPlate and distributed as Bacillus amyloliquefaciens, B. licheniformis, Paenibacillus pabuli, B. atrophaeus, B. subtilis, B. pumilus, and B. endophyticus, respectively. Four antagonists chosen randomly from the 15 bacteria all exhibited the same 100% protective activity in planta as that in the petri dishes. This microassay proved to be a rapid, reproducible, and efficient method for screening of potential biological agents or microorganisms and may be useful for studying mechanisms of infection and control of Phytophthora spp. Under hydroponic conditions. © 2012 The American Phytopathological Society.


Liu W.,Zhejiang University | Shang S.,Guizhou Tobacco Science Institute | Feng X.,Zhejiang University | Zhang G.,Zhejiang University | Wu F.,Zhejiang University
Environmental Toxicology and Chemistry | Year: 2015

Hydroponic experiments were conducted using cadmium (Cd)-sensitive (cv Guiyan 1) and Cd-tolerant (Yunyan 2) tobacco cultivars to evaluate cultivar differences in response to Cd toxicity in the presence of selenium (Se). The results showed that addition of 3μM Se in 50μM Cd solution markedly reduced Cd accumulation in plants, alleviated Cd-induced growth inhibition, and increased nitrogen and chlorophyll contents as well as photosynthetic performance (i.e., net photosynthetic rate, stomatal conductance, and transpiration rate). External Se dramatically depressed Cd-induced O2•-, H2O2, and malondialdehyde accumulation, especially in the sensitive cultivar. Selenium significantly elevated Cd-depressed activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione-peroxidase, and glutathione reductase in the both cultivars after 7-d treatments. Meanwhile, Se counteracted Cd-induced alterations in certain nutrient elements; for example, it significantly increased Zn and Ca concentrations and reduced Mg concentration in both cultivars. Furthermore, Se significantly elevated Cd-depressed H+-K+-adenosine triphosphatase (ATPase), Na+-K+-ATPase, and Ca2+-Mg2+-ATPase activities. The beneficial effect of Se under Cd stress may be related mainly to the increased ATPase activity and reduced Cd uptake and reactive oxygen species accumulation, thus reducing the negative consequences of oxidative stress caused by Cd toxicity. © 2014 SETAC.


Zvobgo G.,Zhejiang University | Hu H.,Zhejiang University | Shang S.,Guizhou Tobacco Science Institute | Shamsi I.H.,Zhejiang University | Zhang G.,Zhejiang University
Environmental Toxicology and Chemistry | Year: 2015

Phosphate (PO43-) has been reported to suppress arsenate (Asv) uptake in plants. However, its effects on controlling the availability of Asv in tobacco genotypes with different arsenic (As) tolerances has not been fully explored. In the present study, the effects of PO43- on Asv uptake were investigated in a hydroponic culture using 2 tobacco (Nicotiana tabacum) genotypes (ZY90 and FSMY) that differed in Asv tolerance. A total of 9 treatment combinations comprising Asv treatments of 0μM, 10μM, and 100μM and PO43- treatments of 0μM, 50μM, and 500μM were used. The results showed that ZY90 had greater reductions in leaf photosynthetic parameters, root and shoot dry weight, length, and nutrient content than did FSMY when exposed to Asv stress. The addition of 500μM external PO43- significantly suppressed Asv (100μM) uptake in both FSMY and ZY90, with the effect being more pronounced in FSMY. Greater PO43- uptake in plants significantly reduced the influx of Asv, causing an increase in photosynthesis and nutrient uptake. Phosphate supply increased superoxide dismutase activity, catalase activity, and malondialdehyde content. The present study showed that PO43- is an effective competitive inhibitor of Asv, and it can be effectively used to control Asv accumulation in tobacco plants. © 2014 SETAC.


Zhang B.,Zhejiang University | Shang S.,Guizhou Tobacco Science Institute | Jabeen Z.,Zhejiang University | Zhang G.,Zhejiang University
Ecotoxicology and Environmental Safety | Year: 2014

The possible involvement of ethylene in alleviating cadmium (Cd) toxicity by NaCl was investigated because our previous experiments showed that a low concentration of NaCl could alleviate Cd toxicity of tobacco plants. Tobacco plants exposed to the treatment of a combination of Cd-NaCl exhibited more vigorous growth than did those exposed to the treatment of Cd stress alone, as reflected by greater biomass, longer roots, taller shoots, larger SPAD values and higher photosynthetic rates. The results also indicated that it is Na+, rather than Cl-, that alleviates Cd toxicity. Cd-NaCl treatments enhanced and inhibited ethylene production in roots and in leaves, respectively, in comparison with the plants exposed to Cd alone. However, the exogenous application of ethylene did not improve root growth under Cd exposure, indicating that ethylene is not directly involved in the rooting process. It may be assumed that the addition of NaCl into the solution containing Cd regulates root growth by mediating ethylene synthesis. © 2013 Elsevier Inc.


Zhang B.,Zhejiang University | Shang S.,Guizhou Tobacco Science Institute | Jabben Z.,Zhejiang University | Zhang G.,Zhejiang University
Ecotoxicology and Environmental Safety | Year: 2014

Nitric oxide (NO) is involved in regulating the response of plants to Cd toxicity. In this study, we examined possible involvement of NO in the alleviation of Cd toxicity by NaCl in tobacco plants. Two independent experiments were conducted to investigate the changes of NO accumulation and Cd concentration in tobacco plants after the addition of a NO donor, sodium nitroprusside dehydrate (SNP), or a NO inhibitor, nitro-. l-arginine methyl ester (l-NAME) in the solution containing NaCl and Cd. NO accumulation in tobacco roots was enhanced when plants were exposed to Cd, but reduced in the treatments of NaCl or l-NAME. NO production was not enhanced even when SNP (NO donor) was added to the solution containing Cd and NaCl. Root number was reduced in plants exposed to Cd, and increased by the addition of NaCl and reduced by the addition of SNP. Addition of NaCl or l-NAME to the Cd-containing solution reduced Cd concentration in plant tissues, with l-NAME having a more dramatic effect. It can be concluded that alleviation of Cd toxicity by NaCl contributed to reduction of NO accumulation in plants. © 2014 Elsevier Inc.


PubMed | Guizhou Tobacco Science Institute and Zhejiang University
Type: Journal Article | Journal: Environmental toxicology and chemistry | Year: 2015

Tobacco easily accumulates certain heavy metals in leaves and thus poses a potential threat to human health. To systematically dissect Cr-responsive microRNAs (miRNAs) and their targets at the global level, 4 small RNA libraries were constructed from the roots of Cr-treated (Cr) and Cr-free (control) for 2 contrasting tobacco genotypes,Yunyan2 (Cr-sensitive) and Guiyan1 (Cr-tolerant). Using high-throughput-sequencing-technology, the authors identified 53 conserved and 29 novel miRNA families. Comparative genomic analysis of 41 conserved Cr-responsive miRNA families revealed that 11 miRNA families showed up-regulation in Guiyan1 but unaltered in Yunyan2, and 17 miRNA families were up-regulated only in Yunyan2 under Cr stress. Only 1 family, miR6149, was down-regulated in Yunyan2 but remained unchanged in Guiyan1. Of the 29 novel miRNA families, 14 expressed differently in the 2 genotypes under Cr stress. Based on a high-throughput degradome sequencing homology search, potential targets were predicted for the 41 conserved and 14 novel Cr-responsive miRNA families. Clusters of Orthologous Groups functional category analysis revealed that some of these predicted target transcripts of miRNAs are responsive to biotic and abiotic stresses. Furthermore, the expression patterns of many Cr-responsive miRNAs were validated by stem-loop real-time transcription polymerase chain reaction. The results of the present study provide valuable information and a framework for understanding the function of miRNAs in Cr tolerance.


PubMed | Guizhou Tobacco Science Institute and Zhejiang University
Type: | Journal: Ecotoxicology and environmental safety | Year: 2014

Nitric oxide (NO) is involved in regulating the response of plants to Cd toxicity. In this study, we examined possible involvement of NO in the alleviation of Cd toxicity by NaCl in tobacco plants. Two independent experiments were conducted to investigate the changes of NO accumulation and Cd concentration in tobacco plants after the addition of a NO donor, sodium nitroprusside dehydrate (SNP), or a NO inhibitor, nitro-l-arginine methyl ester (l-NAME) in the solution containing NaCl and Cd. NO accumulation in tobacco roots was enhanced when plants were exposed to Cd, but reduced in the treatments of NaCl or l-NAME. NO production was not enhanced even when SNP (NO donor) was added to the solution containing Cd and NaCl. Root number was reduced in plants exposed to Cd, and increased by the addition of NaCl and reduced by the addition of SNP. Addition of NaCl or l-NAME to the Cd-containing solution reduced Cd concentration in plant tissues, with l-NAME having a more dramatic effect. It can be concluded that alleviation of Cd toxicity by NaCl contributed to reduction of NO accumulation in plants.


PubMed | Guizhou Tobacco Science Institute and Zhejiang University
Type: | Journal: Ecotoxicology and environmental safety | Year: 2014

The possible involvement of ethylene in alleviating cadmium (Cd) toxicity by NaCl was investigated because our previous experiments showed that a low concentration of NaCl could alleviate Cd toxicity of tobacco plants. Tobacco plants exposed to the treatment of a combination of Cd-NaCl exhibited more vigorous growth than did those exposed to the treatment of Cd stress alone, as reflected by greater biomass, longer roots, taller shoots, larger SPAD values and higher photosynthetic rates. The results also indicated that it is Na(+), rather than Cl(-), that alleviates Cd toxicity. Cd-NaCl treatments enhanced and inhibited ethylene production in roots and in leaves, respectively, in comparison with the plants exposed to Cd alone. However, the exogenous application of ethylene did not improve root growth under Cd exposure, indicating that ethylene is not directly involved in the rooting process. It may be assumed that the addition of NaCl into the solution containing Cd regulates root growth by mediating ethylene synthesis.

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