научный журнал по биологии Физиология растений ISSN: 0015-3303

JIA D., LIU Y.H., MA R.Y., WANG J.S., ZHANG B., ZHANG J.Y., ZHANG P.P. — 2015 г.

The current study was conducted by using suppression subtractive hybridization (SSH) to identify the differentially expressed genes in Alternanthera philoxeroides (Mart.) Griseb. under drought stress and thus to explore the molecular mechanisms of drought tolerance. The mRNA was extracted from the roots of drought-treated and well-watered A. philoxeroides to construct SSH cDNA library. Positive clones were selected for sequencing and further analyzed by BLAST for screening non-redundant and homologous expressed sequence tags (ESTs). Then these ESTs were put into the Gene Ontology database for functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) for metabolic pathways analysis. Four cDNA fragments, ZFP (zinc finger protein), HSP70 (heat shock protein 70), CAT (catalase), and TPS (trehalose-6-phosphate synthase), were randomly chosen for RT-PCR analysis. In the SSH cDNA library, 286 positive clones picked up randomly were sequenced and finally 269 sequences were available. After cluster analysis of the ESTs, 82 unigenes were obtained, in which 63 genes displayed a high homology to known sequences. KEGG analysis found that these genes were involved in 14 metabolic pathways, such as the pathways of plant hormone signal transduction and biosynthesis of secondary metabolites. The expressions of the above four cDNA fragments were all up-regulated in A. philoxeroides under drought stress. This study presented a basis for studying the drought tolerance mechanism of A. philoxeroides, which provided a theoretical basis for managing the spread of this plant.

HADDAD R., JAPELAGHI R.H. — 2015 г.

Peroxiredoxins (Prxs) are peroxidases that reduce hydrogen peroxide (H2O2) and various alkyl hydroperoxides and act as reductants. A full-length cDNA encoding for a Prx polypeptide was isolated and cloned from grape (Vitis vinifera L. cv. Askari) berries. The cDNA was 773 nucleotides in length with a deduced amino acid of 162 residues, possessing one conserved cysteine, which belongs to the type II Prx C. The calculated molecular mass and the predicted isoelectric point of the deduced polypeptide are 17.26 kD and 5.15, respectively. The deduced protein sequence showed a high similarity to PrxII C from other plants, in particular from cotton (Gossypium hirsutum), poplar (Populus trichocarpa), and Citrus sP. The in silico analysis of the promoter region of grape Prx demonstrated the presence of a number of potential cis-acting elements to respond to environmental signals, suggesting that VvPrxII C may respond to a variety of environmental signals, including dehydration, heat, heavy metals, light, pathogens, wounding, and plant hormones. The grape Prx gene was also analyzed for its expressional response to abiotic stress, oxidative stress, and antioxidants application. The results revealed a highly induced response to abiotic stress conditions due to the presence of different putative regulatory elements in its promoter.

CHAI C., GUAN L., HOU S., SONG L., SONG Y., YAN L., YANG J. — 2015 г.

Target of AvrB Operation (TAO1) is a TIR-NB-LRR disease resistance protein that responds to avirulence gene B (avrB). However, whether TAO1 plays a role in Arabidopsis thaliana development and/or abiotic stress is unknown. Here, we found that TAO1 expression is regulated in a tissue-specific manner, and that TAO1 protein is localized to both the plasma membrane and chloroplasts. Moreover, we showed that three tao1 T-DNA insertion mutants had no significant abnormal phenotype. However, we found that TAO1 expression was up-regulated by ethylene precursor ACC and auxin NAA, but down-regulated by ethylene inhibitor AgNO3 and auxin inhibitor NPA, suggesting that TAO1 is coordinately regulated by ethylene and auxin. We also found that endogenous ethylene production decreased in TAO1-overexpression lines, but increased in the tao1-10 T-DNA mutant line compared to the wild type, suggesting that TAO1 may be a negative regulator of ethylene signaling. These novel characteristics shed new light on the role(s) of TAO1 in Arabidopsis independent of its role in disease resistance.

MA X., PAN Y., SONG H., WANG C., WANG H., XU X., YING Q. — 2015 г.

One novel transcription factor gene DnWRKY29 was isolated from Dendrobium officinale, and its functions were identified by it overexpressing in tobacco. Compared to the wild type (WT), the DnWRKY29 transgenic tobacco seeds and seedlings showed the higher sensitivity to salt and drought stresses. The seed germination rate, seedling root length, and fresh weight of transgenic tobacco were lower than in WT. The activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) in transgenic tobacco were decreased, and the content of malondialdehyde (MDA) in transgenic tobacco was increased. Moreover, the expression of DnWRKY29 was up-regulated in Dendrobium seedlings under salt and drought stresses, which is consistent with the function identified by its overexpression in tobacco, indicating that the up-regulation or overexpression of DnWRKY29 impaired plant tolerance to salt and drought stresses. These results provided a new insight to the low tolerance of Dendrobium seedlings to environmental changes.

DONG S.S., LI W.L., WEI Y.L., WU W.L., YANG H.Y., ZHANG C.H. — 2015 г.

In order to study the potential antioxidant defense mechanisms, the blackberry cultivar “Ningzhi 1”, a new floricane-fruiting hybridberry (Rubus sp.), was subjected to 20-day drought stress by withholding irrigation, followed by rewatering for 5 days, then the leaf water content (LWC), membrane electrolyte leakage, contents of photosynthetic pigments, protein, soluble sugar, hydrogen peroxide (H2O2), and malondialdehyde (MDA), activities of superoxide dismutase (SOD) and peroxidase (POD), and the levels of antioxidants such as ascorbate (AsA) and reduced glutathione (GSH) in leaves were investigated. The results showed that LWC was greatly decreased during the 20-day drought treatment period. After rewatering, water content restored. Drought stress induced significant accumulation of photosynthetic pigments, protein, soluble sugar, H2O2, and MDA as well as an increase in membrane electrolyte leakage, which were all decreased after rewatering. The activities of SOD and POD were elevated under drought stress, which were still at higher levels compared with control after rewatering. The contents of AsA and GSH ascended first and were then followed by a decline during the whole drought period, after rewatering, the contents increased and remained at a higher level than that of controls. The plants showed a rapid and almost complete recovery after rewatering, and the physiological alterations could represent a set of adaptive mechanisms employed by “Ningzhi 1” to cope with drought stress. It was suggested that increased drought tolerance of “Ningzhi 1” was due to higher antioxidant enzymes, reduced lipid peroxidation, better accumulation of osmolytes, and maintenance of tissue water content.

EHSANPOUR A.L., RAJAEIAN S.O. — 2015 г.

Plant exposure to stress results in the decomposition of their cell membrane phospholipids, and therefore it can elevate the level of EA (ethanolamine) in the cell, and this elevated level of EA induces an alarm response that activates cellular resistance and tolerance mechanisms. In the present study, in vitro cultured tobacco plants (Nicotiana rustica L.) were pretreated with ethanolamine (EA) before salt treatment. After 3 weeks of salt treatment (200 mM NaCl), the plants pretreated with exogenous EA showed the elevated levels of SOD, CAT and APX activity compared with unpretreated plants. Furthermore, total antioxidant capacity, fresh and dry weight and the content of photosynthetic pigments were also increased. In contrast, H2O2 content decreased under similar conditions. According to the results of this study, it can be suggested that EA pretreatment increased salt tolerance of tobacco plants at least partly by stimulation of antioxidative responses.

ABBAS G., DUMAT C., PINELLI E., POURRUT B., SHAHID M., SHAHID N. — 2015 г.

Chemical speciation of metals in soil/solution plays an important role in determining their biogeochemical behavior in soil–plant system. The current study evaluated the influence of applied form of Pb (metal speciation) on its toxicity to metal sensitive Vicia faba L. roots. Lead was applied to young V. faba seedlings alone or chelated by organic ligands (citric acid and ethylenediaminetetraacetic acid). Plants were exposed to all treatments for 1, 4, 8, 12, and 24 h in nutrient solution, and contents of H2O2 and thiobarbituric-acid-reactive substances (TBARS) production were analyzed in V. faba roots. The results showed that Pb toxicity to V. faba roots depended on its applied chemical form and duration of exposure. Lead alone caused two burst of lipid peroxidation and H2O2 induction at 1 h and 12 h. Addition of EDTA dose-dependently inhibited Pb-induced H2O2 and TBARS production, indicating a protective role of this chelator against Pb toxicity during the first 24 h. In contrast, citric acid did not show significant effects on Pb-induced H2O2 and TBARS production, but delayed the induction of these effects. This study suggested that Pb toxicity to V. faba roots varies with Pb speciation in growth medium.

ABEDINI M., DAIE-HASSANI B. — 2015 г.

Salicylic acid (SA), a naturally occurring plant hormone, is an important signal molecule known to have diverse effects on biotic and abiotic stress tolerance. In this study the effects of exogenous application of different levels of SA (0, 250, and ) in hydroponic culture on hydrogen peroxide (H2O2) and malondialdehyde (MDA) generation, the content of soluble proteins and activities of antioxidative enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in shoots of two wheat (Triticum aestivum L.) cultivars (Azar2 and Chamran) under different concentrations of NaCl (0, 75, and 150 mM) were investigated. Concentration of 150 mM NaCl induced deleterious effects in both wheat cultivars. Application of SA was effective in alleviation of salt stress. Activities of SOD, POD, and CAT enzymes were augmented by SA treatments. The highest SOD and POD activities were recorded at SA + 150 mM NaCl, while CAT activity was increased at 250 SA + 75 mM NaCl. As increasing antioxidative enzyme activities, SA decreased H2O2 and MDA contents of the seedlings grown under salt stress.

ALCARAZ-MELENDEZ L., AYALA-CASTRO H.G., SORIANO-MELGAR L.A.A. — 2015 г.

Salinity is an unfavourable factor to plant growth, development, and quality because high salinity increases oxidative stress and damage in plants. Damiana (Turnera diffusa Willd.) plants grow in arid zones. They are socio-economically important as they have industrial potential. Currently, no reports on their tolerance to salinity are available. This study was performed to determine the effect of salinity in damiana plants in an in vitro model under controlled conditions by applying NaCl in three levels (0.1, 1.0, and 1.5%) in Murashige-Skoog medium. To prove decrease in salinity stress, exogenous salicylic acid (SA) treatments (1 and 10 ppm) were tested, and biomass and water content were determined. Photosynthetic pigments and their degradation were determined with high performance liquid chromatography to assess the degree of salinity damage. To define the adaptation mechanism to salinity, specific peroxidase (POX) activity was quantified by spectrophotometric assay. Results showed that the determined parameters (chlorophyll a, chlorophyll b, -carotenes, pheophytin, violaxanthin, and zeaxanthin contents) reduced progressively with increase in salinity level. Chlorophyllide a and pheophorbide a contents were not modified by salinity stress but responded to SA presence. POX activity increased in all treatments with plants supplemented with NaCl. Treatments by SA did not modify the negative effects of NaCl on the photosynthetic pigments, but even so significantly enhanced POX activity compared with the untreated stressed plants (NaCl without SA). The results showed that damiana plants were moderately salt-tolerant and could be grown in soils with such characteristics.

HU X., LI H., LIU D., LU H., MU Y., REN L., ZHAO Y. — 2015 г.

Telomeres have lately received considerable attention in the development of deciduous tree species. In order to determine season-specific changes in telomere length and telomerase activity in evergreen tree species, Chinese pine trees (Pinus tabulaeformis Carr.) were used as experimental materials. In this study, we examined the correlation among telomere length, telomerase activity, and temperature in P. tabulaeformis during the course of an annual developmental cycle. A statistical analysis showed that the lengths of telomeres were significantly different between new and old leaves in each month. During the annual developmental cycle, the telomere lengths in Chinese pine tree leaves increased from May to June 2012, remained stable or increased slightly from June to August 2012, decreased sharply from August 2012 to January 2013, and then increased from January to April 2013. Telomerase activities could be detected in both new and old leaves from May 2012 to April 2013 and the telomerase activities in new leaves are higher than in the old each month. Additionally, there were similar trends between the changes in telomere length and mean monthly temperature from May 2012 to April 2013, and opposite trends were shown between the changes in telomerase activity and mean monthly temperature. Therefore, telomere length and telomerase activity varied with the season. Telomere length was positively correlated with temperature and telomerase activity was negatively correlated with temperature during the annual developmental cycle.

BAI X.Y., CHEN Z.P., GAO Q.C., HE X.L., JIANG L., XU Q.X., ZHANG J.J. — 2015 г.

We isolated the Arabidopsis drought-resistant mutant csm1-1 and cloned the CSM1 gene (previously called RCI3) which encodes a kind of peroxidase. In this study, we showed that the mutant csm1-1 was more tolerant to selenium (Se) stress than the wild-type, and that the mutant csm1-1 accumulated similar Se content compared with the wild-type when subjected to Se stress. Further analysis revealed that the Se resistance of mutant csm1-1 was associated, at least in part, with the enhanced activities of antioxidant enzymes GSH-POD (glutathione peroxidase) and POD (peroxidase). In addition, enhanced Se resistance of the mutant csm1-1 was partially GSH dependent, which was related to the higher expression level of GSH1 gene involved in GSH synthesis and consequently increased GSH content.

LI Z.G., LUO L.J., SUN Y.F. — 2015 г.

Hydrogen peroxide (H2O2) and nitric oxide (NO) function as signal molecules in plant cells. Recently, hydrogen sulfide (H2S) has been found to have similar functions, but their interactions in the acquisition of thermotolerance in plants remain elusive. In current work, pretreatment with H2O2 rapidly induced endogenous H2O2 accumulation, which in turn improved survival percentage of maize seedlings (Zea mays L.) under heat stress, but these effects were eliminated by H2O2 scavenger dimethylthiourea (DTMU), indicating that H2O2-induced thermotolerance was involved in the accumulation of endogenous H2O2. H2O2 pretreatment also increased endogenous NO content, but this increase was abolished by NO scavenger cPTIO. Exogenously applied H2O2 also stimulated increase in the activity of L-cystine desulfhydrase, a key enzyme in H2S biosynthesis, followed by inducing endogenous H2S accumulation, while this accumulation was diminished by cPTIO. In addition, H2O2-induced thermotolerance was enhanced by NO donor sodium nitroprusside (SNP) and H2S donors NaHS as well as GYY4137, respectively, and weakened by cPTIO, DL-propargylglycine (PAG, inhibitor of H2S biosynthesis) and hypotaurine (HT, H2S scavenger). All of the above-mentioned results showed that H2O2 treatment could improve thermotolerance in maize seedlings, and the acquisition of thermotolerance induced by H2O2 may be involved in downstream signal crosstalk between NO and H2S.

FAN Y., LI L., LIU J., WANG X.F., WANG X.Z., YANG T., ZHU X. — 2015 г.

The acidic fibroblast growth factor (aFGF) is a member of FGF family which is composed of 154 amino acids. In order to explore the functional anti-aFGF single-chain variable fragment antibody (scFv) expression in eukaryote system and to enhance the binding activity, the functional scFv specific for human aFGF was expressed in tobacco plants via TMV vector mediated by Agrobacterium. The engineered bacterial EHA105: p35S-30B-scFv was inoculated into the leaves of Nicotiana benthamiana plants by needle-less injection. Green fluorescence protein was used as a reporter gene and accumulated at the highest level on the 8th day of post-inoculation. Expression of scFv was identified by RT-PCR and Western-blot. The yield of anti-aFGF-scFv protein was reached to 0.5% of the plant total soluble proteins and a fair binding activity with its antigen aFGF was detected.

IVANOVA J.G., KABAIVANOVA L.V., PETKOV G.D. — 2015 г.

The red microalga Rhodella reticulata, a potential source of bioactive substances, was the subject of study of the irradiance and temperature effects on growth rate and biochemical composition of algal biomass. The optimum temperature for growth decreased from 28 to 26°C with increasing light intensity from 260 to s). The maximal growth rate was 0.21/day at 28°C and lower light intensity (260 s)). Variations in these parameters also affected the fatty acid productivity, and proteins and carbohydrates content. At 34°C and high light intensity the quantity of carbohydrates was 1.16-fold higher than the quantity at the optimal temperature and low light intensity. Protein content was the highest at lower temperatures for both light intensities. Fatty acid profile showed the highest percent for the polyunsaturated eicosapentaenoic acid (EPA) at 28°C and both light intensities (46% from the whole fatty acid content), an important feature for this strain. This is a prerequisite for use of EPA as a supplement in food industry.

CHEREPNEVA G.N., DEMIDENKO A.V., KARAVAIKO N.N., KAZAKOV A.S., KUDRYAKOVA N.V., KULAEVA O.N., KUSNETSOV V.V., OELMULLER R., PERMYAKOV S.E., SHEVCHENKO G.V. — 2015 г.

We characterized AA1 ( acid ), a protein from Lupinus luteus L. predicted to be located in the apoplastic space whos mRNA and protein levels are strongly regulated by ABA, salt stress, and hypothermia. A fragment from the recombinant AA1 protein binds ABA as shown by the spectrofluorimetric titration assay of the protein by ABA. The BLAST software of the DFCI database identified more than 200 ESTs from 46 dicots and monocots, including three genes with unknown function from Arabidopsis thaliana, which are closely related to the lupine AA1. The central part of the proteins encoded by these genes contains the TolB motif from Escherichia coli and shares conserved WD40-like repeats, which form the basis for the tertiary beta-propeller structure and provide a potential platform for the assembly of protein complexes. Our data suggest that the highly conserved AA1 proteins from L. luteus and other higher plants are involved in ABA-mediated responses.

JIN H., QIN B., WANG D.D., YAN Z.Q., YANG X.Y. — 2015 г.

Gravitropism is affected by many exogenous factors such as environmental stresses. In the present study, the effect of ellagic acid (EA) on the gravitropic curvature of Arabidopsis thaliana (L.) Heynh. roots was characterized. Exogenous application of EA influenced root gravitropic responses in a concentration-dependent fashion. KI/I staining research revealed that the starch grain in the root cap was reduced by EA treatments. Simultaneously, expression of auxin-responsive reporter gene DR5::GFP showed that the auxin redistribution in roots treated with EA was less sensitive to that of control groups under gravity stimulus. Moreover, the expression of one of the auxin flux-facilitators – PIN2, was also suppressed by EA. Taken together, our results indicated that the effects of EA on root gravitropism were largely dependent on the reduction of starch grain and the disorder of lateral auxin redistribution.

BEDNAREK W., DRESLER S., HANAKA A., TUKIENDORF A., WOJCIK M. — 2015 г.

The effects of silicon (Si) supply (0, 0.1, 0.5, 1.5, 3.0, and 5.0 mM Si) on maize seedling growth, Si and Cd accumulation, and thiol peptide synthesis under Cd stress conditions were studied. The addition of Si to the growth medium resulted in the significantly higher Si accumulation in plant tissues. The average values of growth parameters (root and shoot fresh weights and root net elongation rates – NER) showed a beneficial role of Si on growth of non-Cd-treated plants, while there was no evidence that silicon mitigated Cd toxicity in maize seedlings. Cadmium exposure depressed plant growth and induced phytochelatin (PC) synthesis. The accumulation of Cd and PCs in roots significantly decreased with increasing Si concentrations in the nutrient solution; however, their accumulation in shoots was not changed in the presence of Si.

CHEN H.Z., DUAN X.L., HAN R. — 2015 г.

Regulator of Chromosome Condensation 1 (RCC1), a Guanine Nucleotide Exchange Factor (GEF) for the small Ran GTPase (Ran-GTP), is localized on chromatin in the nucleus where it mediates the generation of Ran-GTP. The production of Ran-GTP by RCC1 is critical for nuclear envelope formation, nucleocytoplasmic transport, DNA replication, and chromosome-induced mitotic spindle assembly. Most of the previous studies on RCC1 were carried out in mammalian cells. Only few studies on RCC1 in plant cell have been reported. Here we present an investigation on the identification of RCC1 and its location in wheat (Triticum aestivum L.) somatic cells during mitosis using immunoblotting and immunofluorescence. It was postulated that RCC1 are richer in chromatin than the surrounding cytoplasm throughout mitosis. Compared with white light, enhanced UV-B radiation greatly reduced the content of RCC1 (immunoblotting) and its fluorescence intensity. When RCC1 was absent, laser scanning confocal microscope detected the abnormal chromosomes. The results indicated that the participation of RCC1 in cell cycle provided theoretical basics for revealing the mechanism of abnormal mitosis caused by enhanced UV-B radiation and guided practical significance for agricultural production.

GHASSEMI-GOLEZANI K., LOTFI R. — 2015 г.

The ameliorative effect of SA and Si on PSII activity of mung bean plant under salt stress (control, 3, 6, and 9 dS/m) was studied by chlorophyll a fluorescence measurement. Results showed that Na+ accumulation decreased, but K+ accumulation increased in mung bean (Vigna radiata (L.) Wilczek) leaves by application of Si and especially SA, leading to improvement in PSII activity under salinity. Initial fluorescence (F0) and energy necessary for the closure of all reaction centres (Sm) were increased with increasing salt levels. Exogenous foliar application of SA and Si decreased initial fluorescence (F0) and increased photosynthesis relative vitality (PI). Maximum fluorescence (Fm), variable fluorescence (Fv), the activity of the water-splitting complex on the donor side of the PSII (proportional to Fv/F0) and the average redox state of QA in the time span from 0 to Tfm (Sm/Tfm) were also enhanced by foliar application of SA. Exogenous application of SA improved maximum quantum efficiency of PSII (Fv/Fm) and performance index (PI) under both saline and non-saline conditions. Increasing in the size of the plastoquinone pool (Area) was much greater for SA than that for Si treated plants. It was concluded that foliar application of Si and SA in particular could play a key role in salt stress tolerance of mung bean plants.

DUANGSRISAI S., WONGKANTRAKORN N. — 2015 г.

Unspliced (L-SDH) and spliced (S-SDH) transcripts of NAD+-dependent sorbitol dehydrogenase (NAD-SDH) of strawberry (Fragaria ananassa Duch., cv. Nyoho) were investigated. Fructose, mannitol, and IAA increased S-SDH transcript level. Sorbitol decreased the level of L-SDH transcript 2.5-fold. ABA and benzyladenine (BA) decreased S-SDH transcript level and increased L-SDH transcripts. Ratio of S-SDH to L-SDH was increased by sorbitol (2.7-fold), fructose (2.2-fold), and IAA (1.5-fold), and decreased by BA (4-fold) and ABA (1.7-fold) as compared to control. These results suggest that sorbitol, fructose, and IAA stimulated splicing of pre-mRNA of NAD-SDH, but BA and ABA repressed this process.