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Carbon nutrition of mature green orchid Serapias strictiflora and its mycorrhizal fungus Epulorhiza sp.K. Látalová, M. BaláľBiologia plantarum 54:97-104, 2010 | DOI: 10.1007/s10535-010-0014-2 We studied the nutritional modes of the orchid Serapias strictiflora and its mycorrhizal fungus Epulorhiza sp. using the differences in carbon isotopic composition (δ13C) of C3 orchid and C4 maize tissues. We found that if cultivated in substrate lacking any organic compounds, the mycorrhizal extraradical mycelia (δ13C = -26.3 ± 0.2 ‰) developed well, despite being fully dependent on nutrition from orchid roots (δ13C = -28.6 ± 0.1 ‰). If the mycorrhizal fungus had additional access to and colonized decaying maize roots (δ13C = -14.6 ± 0.1 ‰), its isotopic composition (δ13C = -21.6 ± 0.4 ‰) reflected a mixture of biotrophy and saprotrophy. No statistically significant differences in δ13C of new storage tubers were found between Epulorhiza-associated orchids with (δ13C = -28.2 ± 0.1 ‰) and without access to maize roots (δ13C = -28.6 ± 0.2 ‰). We conclude that autotrophy is the predominant nutritional mode of mature S. strictiflora plants and that they supply their mycorrhizal fungus with substantial amount of carbon (69 ± 3 % of the fungus demand), even if the fungus feeds saprotrophically. |
Optimization of Algerian fir somatic embryos maturationB. Vooková, J. Machava, A. ©algovičová, A. Kormu»ákBiologia plantarum 54:177-180, 2010 | DOI: 10.1007/s10535-010-0030-2 The effect of maturation pretreatment on development and growth of Abies numidica De Lann. somatic embryos was studied. The most beneficial was pre-culturing on Schenk and Hildebrandt medium without growth regulator for 2 weeks. Dry mass accumulation of emblings was lower than that of seedlings after 50 d of culturing. Contents of microelements in seedlings were higher than in emblings, but macroelements contents were higher in emblings. Contents of chlorophyll a and chlorophyll b in cotyledons were higher in seedlings than in emblings while no qualitative differences were detected between the protein profiles of seedlings and emblings. |
The lack of plastidal transit sequence cannot override the targeting capacity of Bradyrhizobium japonicum δ-aminolevulinic acid synthase in transgenic riceK. Back, S. JungBiologia plantarum 54:279-284, 2010 | DOI: 10.1007/s10535-010-0049-4 The δ-aminolevulinic acid synthase (ALA-S) is an enzyme which catalyzes the synthesis of δ-aminolevulinic acid (ALA). The Bradyrhizobium japonicum ALA-S coding sequence lacking plastidal transit sequence was introduced into the rice genome (C line). The transgenic lines, C4 and C5, were compared with the transgenic lines expressing TALA-S gene with plastidal transit sequence (P line) to investigate whether the plastidal sequence affects the targeting capacity of B. japonicum ALA-S gene and the ALA-synthesizing capacity in rice plants. The B. japonicum ALA-S mRNA was expressed efficiently in C lines and the protein was localized in the stroma of chloroplasts regardless of the transit sequence as in P lines. The resulting transgenic plants, C line, had similar levels of ALA-S activity, ALA, protoporphyrin IX and chlorophylls, compared to those of P lines. In response to irradiance of 350 μmol m-2 s-1, transgenic lines C4 and C5 displayed the characteristic phenotypes of photodynamic damage, i.e., decreases in photosynthetic parameter Fv/Fm, as in P5 and P14 lines, whereas wild type did not. These results indicate that the lack of the plastidal transit sequence influences neither chloroplast translocation of B. japonicum ALA-S nor ALA-synthesizing capacity in the transgenic rice. |
Tree water dynamics non-destructively assessed through sap flow measurements and potential evapotranspirationR. Bequet, J. Čermák, N. Nadezhdina, C. De Canniere, R. CeulemansBiologia plantarum 54:366-368, 2010 | DOI: 10.1007/s10535-010-0065-4 Sap flow and potential evapotranspiration rates were analyzed for two coniferous tree species (Douglas-fir and Scots pine) and one broadleaf species (sessile oak) in a mixed Carpineto-Quercetum forest during the growing season 2005. The relationship between sap flow and potential evapotranspiration rates, effective crown area as a measure of the relative transpiration and daily relative proportion of the storage water used for transpiration were used as indicators of the tree water dynamics. These indicators were determined on four consecutive days and all three showed good reliability concerning tree water dynamics. |
Transient expression of human papillomavirus type 16 virus-like particles in tobacco and tomato using a tobacco rattle virus expression vectorM. ©mídková, M. Müller, N. Thönes, K. Piuko, P. Angelisová, J. Velemínský, K. J. AngelisBiologia plantarum 54:451-460, 2010 | DOI: 10.1007/s10535-010-0081-4 The major capsid protein L1 of human papillomavirus type 16 (HPV16) was transiently expressed in tobacco (Nicotiana benthamiana and Nicotiana tabacum) and tomato (Lycopersicon esculentum) leaves using Agrobacterium tumefaciens. The expression vector pTV00 was derived from tobacco rattle virus (TRV). The highest L1 expression 15 μg g-1(f.m.) was achieved when the coding sequence of L1 was optimized for expression in humans that caused an increase of the guanine and cytosine (GC) content from 38.2 % in wild type HPV16 to 64.1 % in optimized sequence. L1 monomers readily self-assembled into capsomeres and further into virus like particles (VLPs). Immunological characterization and electron microscopy showed that 89 % of L1 retained VLP structure also in extracts prepared from freeze-dried leaves. Plant expressed L1 in crude extracts was highly immunogenic without any additional adjuvant as vaccinated mice developed strong humoral and cellular immune response, comparable to that elicited by purified VLPs derived from insect cells. Further, the induced antibodies effectively neutralized infection of 293TT cells with pseudovirions. This finding demonstrates that the TRV expression system is comparable to other plant expression systems and due to the broad host range of TRV is particularly attractive when expression in plants with low content of toxic alkaloids is desired. Moreover, a monoclonal anti-L1 antibody E2 raised in the course of immunization with crude extract from freeze-dried leaves expressing L1 is specific preferentially against HPV VLPs and could be used in direct ELISA for monitoring of VLPs assembly and VLP purification protocols. |
Storage and conversion of Eclipta alba synseeds and RAPD analysis of the converted plantletsA. Ray, S. BhattacharyaBiologia plantarum 54:547-550, 2010 | DOI: 10.1007/s10535-010-0097-9 The encapsulated shoot tips and nodal segments of Eclipta alba were stored at 4, 12 and 20 °C under irradiance of 1.5 gmmol m-2 s-1 and high conversion was observed in synseeds stored at 4 °C for 8 weeks. Duration of storage was extended up to 12 weeks by decreasing sucrose concentration in the alginate matrix from 3 to 1 or 2 % and conversion frequency was 71.2-76.1 %. Synseed-derived plantlets survived by 100 % in ex vitro conditions. RAPD analysis revealed uniform amplification profile in donor and synseed derived plantlets. |
Ectopic over-expression of two apple Flowering Locus T homologues, MdFT1 and MdFT2, reduces juvenile phase in ArabidopsisW. M. Li, Y. Tao, Y. X. Yao, Y. J. Hao, C. X. YouBiologia plantarum 54:639-646, 2010 | DOI: 10.1007/s10535-010-0114-z To get insight into mechanism by which apple tree (Malus domestica Borkh.) regulates flowering, two apple flowering locus T (FT) homologues, MdFT1 and MdFT2, were isolated from the leaf cDNAs of cultivar Gala. The open reading frames (ORFs) of two MdFTs encoded 174 amino acids. The deduced amino acid sequence of MdFT1 and MdFT2 showed 94.3 % similarity to each other, while 72.6 and 76.0 % to AtFT protein, respectively. Semi-quantitative RT-PCR indicated their specific expression in leaves. Visualization of MdFT2-GFP fusion protein demonstrated its localization on membrane. Ectopic overexpression of either MdFT1 or MdFT2 in Arabidopsis significantly induced early flowering by activating the downstream flowering-related genes. |
Effect of photoperiod during growth of Chenopodium rubrum mother plants on properties of offspringA. Mitrović, J. Bogdanović, Z. Giba, L. ĆulafićBiologia plantarum 54:735-739, 2010 | DOI: 10.1007/s10535-010-0131-y Using in vitro culture, we determined the effect of photoperiod during growth of Chenopodium rubrum mother plants on vegetative and reproductive development of offspring. Photoperiod during flowering induction of mother plants (the first 6 d after the germination) has the key influence on seed germination and offspring growth, while offspring flowering and seed maturation is determined by photoperiod their mothers experienced during, and shortly after, flowering induction. The mechanism can be through changes in seed protein pattern which we found dependent on photoperiod experienced by mother plants. |
Genetic diversity for morphological traits and seed storage proteins in Spanish rivet wheatS. Carmona, J. B. Alvarez, L. CaballeroBiologia plantarum 54:69-75, 2010 | DOI: 10.1007/s10535-010-0010-6 The objective of the current work was to analyse the variability of high and low molecular mass (HMM and LMM) glutenin subunits, along with some morphological characteristics in sixty Spanish accessions of rivet wheat (Triticum turgidum L. ssp. turgidum). The lines were grouped in sixteen botanical varieties and five additional types, according the morphological criteria. Up to 13 allelic variants (four alleles for the Glu-A1 locus and nine alleles for the Glu-B1 locus) and 34 B-LMMGs patterns were found in the evaluated lines. The current data indicated a clear reduction of morphological variability, along with an asymmetric distribution of the alleles and patterns for seed storage proteins. This polymorphism could be useful for enlarging the genetic background of modern durum wheat. |
Characterization of a xylanase inhibitor TAXI-I from wheatX. -Y. Weng, Y. -Y. Huang, H. Gao, J. -Y. SunBiologia plantarum 54:154-158, 2010 | DOI: 10.1007/s10535-010-0025-z Xylanase inhibitor TAXI-I gene was cloned from wheat (Triticum aestivum L.) and then TAXI-I encoding sequence was expressed in Escherichia coli. The recombinant TAXI-I protein inhibited glycoside hydrolase (GH) family 11 xylanases in Aspergillus niger (Anx; a fungal xylanase), and Thermomonospora fusca (Tfx; a bacterial xylanase), and also inhibited hybrid xylanases Atx (a hybrid xylanase whose parents are T. fusca and A. niger) and Btx (a hybrid xylanase whose parents are T. fusca and Bacillus subtilis). Among the tested xylanases, A. niger xylanase was the most inhibited one by wheat xylanase inhibitor TAXI-I, while T. fusca xylanase was the least inhibited one. The profile of TAXI-I gene expression in wheat in response to phytohormones was also investigated. TAXI-I gene expression was drastically induced by methyl jasmonate (MeJa), and hardly detected in gibberellic acid (GA) treatment. Therefore, TAXI-I might be involved in plant defense against fungal and bacteria xylanases. |
Cytogenetic analysis of hybrids derived from wheat and Tritipyrum using conventional staining and genomic in situ hybridizationG. Mirzaghaderi, G. Karimzadeh, H. S. Hassani, M. Jalali-Javaran, A. BaghizadehBiologia plantarum 54:252-258, 2010 | DOI: 10.1007/s10535-010-0044-9 The new salt tolerant cereal, Tritipyrum (2n=6x=42, AABBEbEb) offers potential to introduce desirable characters for wheat improvements. This study was aimed to generate a segregating population from Iranian local wheat cultivars (2n=6x=42, AABBDD) and Tritipyrum crosses, study of the meiotic behaviour in F2 hybrids and identification of Eb chromosomes in F3 individuals. Results showed meiotic abnormalities in F2 plants and different pairing frequency in the meiosis among F2 plants. Genomic in situ hybridization revealed that total and Eb chromosome number of F3 seeds ranged from 39 to 45 and 0 to 10, respectively. A significant prevalence of hyper-aneuploidy was observed among F3 genotypes. C-banding patterns identified Eb chromosomes in Tritipyrum, indicating that it also can be useful to study wheat-Tritipyrum derivatives. |
Efficient production of transgenic tomatoes via Agrobacterium-mediated transformationP. Kaur, K. C. BansalBiologia plantarum 54:344-348, 2010 | DOI: 10.1007/s10535-010-0060-9 Cotyledonary leaves of 9-d-old tomato (Lycopersicon esculentum Mill.) were co-cultivated with Agrobacterium tumefaciens GV 3101 harboring binary vector pBI101 containing kanamycin resistance gene (npt II) as selection marker. Murashige and Skoog (MS) inorganic salts with Gamborg's B5 vitamins supplemented with optimized concentrations of zeatin riboside and indole-acetic acid resulted in enhanced regeneration efficiency. Under optimized conditions of plant regeneration, transformation frequency in cvs. Pusa Ruby, Pusa Uphar and DT-39 was greater than 37 %. Transformed shoots were selected on kanamycin medium and the presence of the transgene in the primary transformants was confirmed by PCR. Integration of the npt II gene in the tomato genome was further confirmed by Southern blot analysis. RT-PCR analysis using neomycin phospho-transferase (npt II) gene-specific primers confirmed the expression of the transgene in transgenic plants. Transformed plants were successfully transferred to phytotron, where these plants grew to maturity and produced flowers and fruits. |
Chlorophyll fluorescence in micropropagated Rhododendron ponticum subsp. baeticum plants in response to different irradiancesM. L. Osório, J. Osório, A. RomanoBiologia plantarum 54:415-422, 2010 | DOI: 10.1007/s10535-010-0076-1 The aim of this study was to investigate acclimation of micropropagated plants of Rhododendron ponticum subsp. baeticum to different irradiances and recovery after exposure to high irradiance. Plants grown under high (HL) or intermediate (IL) irradiances displayed higher values of maximum electron transport rate (ETRmax) and light saturation coefficient (Ek) than plants grown under low irradiance (LL). The capacity of tolerance to photoinhibition (as assessed by the response of photochemical quenching, qp) varied as follows: HL > IL > LL. Thermal energy dissipation (qN) was also affected by growth irradiance, with higher saturating values being observed in HL plants. Light-response curves suggested a gradual replacement of qp by qN with increasing irradiance. Following exposure to irradiance higher than 1500 μmol m-2 s-1, a prolonged reduction of the maximal photochemical efficiency of PS 2 (Fv/Fm) was observed in LL plants, indicating the occurrence of chronic photoinhibition. In contrary, the decrease in Fv/Fm was quickly reverted in HL plants, pointing to a reversible photoinhibition. |
Spatial and temporal dynamics of peroxidase and amine oxidase activity is linked to polyamines and lignin in wheat grainsB. Asthir, S. Kaur, W. Spoor, T. RoitschBiologia plantarum 54:525-529, 2010 | DOI: 10.1007/s10535-010-0092-1 The regulation of contents and activities of peroxidase (POX), diamine oxidase (DAO) and polyamine oxidase (PAO) were determined in relation to polyamines and lignin content in wheat (Triticum aestivum L.) grains. Two cultivars WH 542 (heat susceptible) and PBW 343 (heat tolerant) were used. Activities of POX, DAO and PAO were substantially higher in PBW 343 as compared with WH 542 and appeared to be independently regulated. POX and PAO showed peak activities at mid-milky stage (15 d post anthesis) while the activity of DAO showed continuous decline. Histochemical localization of POX and PAO in situ revealed their presence in the chalazal cell walls, crease and seed coat. Substantially higher activities of enzymes in PBW 343 correlated well with a higher degree of lignification in the chalazal cells as compared to WH 542. |
Factors affecting in vitro propagation and field establishment of Chlorophytum borivilianumA. Kumar, D. Aggarwal, P. Gupta, M. S. ReddyBiologia plantarum 54:601-606, 2010 | DOI: 10.1007/s10535-010-0109-9 The effect of plant growth regulators (PGRs), gelling agents, sucrose and heat shock on shoot multiplication, shoot growth, rooting and subsequent survival of Chlorophytum borivilianum Sant. et Fernand was evaluated. Benzyladenine (BA) was found to be better cytokinin over kinetin (KIN) for shoot multiplication. Sucrose concentrations from 116-290 mM in the basal medium (BM) promoted shoot multiplication. Heat shock (50 °C, 1 h) also promoted shoot multiplication at these sucrose concentrations on both BM medium and BM supplemented with 5.0 μM BA. Beneficial effect of sucrose was also observed on rooting of shoots on BM as well as BM supplemented with 5.0 μM indole-3-butyric acid (IBA). Phytagel as a gelling agent was found to be more effective for shoot proliferation and growth compared to agar. Amongst various soil mixtures tested, higher survival of plants was observed in soil containing Vermicompost. It was interesting to note that a maximum plant survival (> 95 %) was observed when plants were directly transferred to net-house (irradiance reduced to 50 % with green net, without humidity and temperature control) than poly-house (with humidity and temperature control). Random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analysis of regenerated plants showed genetic similarity to mother plant. |
Production of transgenic Pinus armandii plants harbouring btCryIII(A) geneX. Z. Liu, Z. Liu, Y. M. Yang, H. Y. ZhangBiologia plantarum 54:711-714, 2010 | DOI: 10.1007/s10535-010-0126-8 A synthetic chimeric gene SbtCryIII(A) encoding the insecticidal protein btCryIII(A), was transformed into Pinus armandii embryos and embryogenic calli using Agrobacterium tumefaciens. Polymerase chain reaction and genomic DNA Southern blot analysis showed that the SbtCryIII(A) gene was integrated into the genome of transgenic Pinus armandii plants, and Northern blot analysis indicated that the SbtCryIII(A) gene was transcribed. |
The effects of brassinosteroids on photosynthetic parameters in leaves of two field-grown maize inbred lines and their F1 hybridM. Kočová, O. Rothová, D. Holá, M. Kvasnica, L. KohoutBiologia plantarum 54:785-788, 2010 | DOI: 10.1007/s10535-010-0143-7 The effect of foliar spray with 10-12 M aqueous solutions of 24-epibrassinolide or a synthetic androstane analogue of castasterone on the activity of photosystem (PS) 1, the Hill reaction activity, the content of photosynthetic pigments and the specific leaf mass was examined for three different leaves developed after brassinosteroid (BR) treatment in two inbred lines of field-grown maize and their F1 hybrid. The brassinosteroids significantly affected neither the efficiency of photosynthetic electron transport, nor the content of chlorophylls or carotenoids. |
Molecular cloning and characterization of a novel microsomal oleate desaturase gene DiFAD2 from Davidia involucrata BaillN. Lei, S. Peng, B. Niu, J. Chen, J. Zhou, L. Tang, Y. Xu, S. Wang, F. ChenBiologia plantarum 54:41-46, 2010 | DOI: 10.1007/s10535-010-0006-2 In the conversion of oleic acid to linoleic acid, δ12-fatty acid desaturase (δ12-FAD) is involved. Based on the conserved oligo amino acid residues of the FAD2 genes from other plants, a new full-length cDNA (DiFAD2) encoding a δ12-FAD was cloned from Davidia involucrata Baill. Sequence analysis indicated that the DiFAD2 gene had an open reading frame (ORF) of 1 149 bp, coding for 382 amino acids residues of 44.3 kDa, pI of the deduced protein was 8.8. The deduced amino acid sequence of the cloned DiFAD2 showed high identities to those genes of other plant δ12-FAD. RT-PCR showed that DiFAD2 was expressed in all tissues and expression was abundant in young stems. Expression of DiFAD2 is not enhanced by low temperature and the altered polyunsaturated fatty acid content in leaves treated with low temperature may be due to the post-transcriptional regulation of the DiFAD2 gene or the other FAD2 gene family regulation. |
Efficient regeneration of Eucalyptus urophylla from seedling-derived hypocotylsZ. -C. Huang, F. -H. Zeng, X. -Y. LuBiologia plantarum 54:131-134, 2010 | DOI: 10.1007/s10535-010-0020-4 Seedling hypocotyls were used as explants to establish a regeneration protocol for Eucalyptus urophylla and N-phenyl-N'-[6-(2-chlorobenzothiazol)-yl] urea (PBU), one kind of di-substituted urea, was found useful growth regulator. The hypocotyls incubated on a modified Murashige and Skoog medium (SPCa), supplemented with 6.6 μM PBU and 0.57 μM indole-3-acetic acid (IAA) dedifferentiated and form calli (100 % after 7 d). Compared with other growth regulator combinations, PBU stimulated more vigorous calli and restrained their darkening. In addition, the calli induced by PBU showed high frequency of adventitious buds formation (57%). Shoot proliferation and elongation was then stimulated on SPCa medium containing 0.44 μM 6-benzyladenine (BA), 0.54 μM naphthalene acetic acid (NAA) and 0.3 μM gibberellic acid (GA3). For rooting, shoots were cultivated on root induction medium containing 2.5 μM indole-3-butyric acid (IBA). Plantlets were then successfully transplanted to greenhouse. |
Transcription factors in plants and ABA dependent and independent abiotic stress signallingP. K. Agarwal, B. JhaBiologia plantarum 54:201-212, 2010 | DOI: 10.1007/s10535-010-0038-7 Plants face variable environmental stresses that negatively affect plant growth and productivity. The multiplicity of responses is an important aspect of the complexity of stress signalling. Abscisic acid (ABA) is a broad-spectrum phytohormone involved not only in regulating stomatal opening, growth and development but also in coordinating various stress signal transduction pathways in plants during abiotic stresses. The both ABA-dependent and ABA-independent signal transduction pathways from stress signal perception to gene expression involve different transcription factors such as DREB, MYC/MYB, AREB/ABF, NAM, ATAF1,2, CUC and their corresponding cis-acting elements DRE, MYCRS/MYBRS, ABRE, NACRS. Genetic analysis of ABA mutants has given insight that ABA-dependent and ABA-independent pathways for osmotic stress and cold stress interact and converge. This review focuses on ABA-dependent and ABA-independent transcriptional components and cascades, their specificity and crosstalk in stress gene regulation. |
Involvement of arabinogalactan proteins in the control of cell proliferation of Cucurbita pepo suspension culturesA. Ben Amar, P. Cobanov, A. Ghorbel, A. Mliki, G. M. ReustleBiologia plantarum 54:321-324, 2010 | DOI: 10.1007/s10535-010-0055-6 Arabinogalactan proteins (AGPs) secreted by zucchini squash (Cucurbita pepo L.) cell cultures into the medium are implicated in cell proliferation. Conditioned medium derived from cell suspensions of squash cultivar Dundoo could enhance multiplication rate of slow-growing cell line Cx3005. To examine the role of AGPs, a precipitation assay was performed using Yariv reagent which binds selectively to AGPs. This AGP precipitation as well as proteinase application arrested cell division. However, chitinase treatment successfully increased embryogenic callus mass. A growth promotion was also obtained by arabinogalactan addition to the culture medium. Immunoblotting analysis using the MAC 207 anti-AGP monoclonal antibody showed high AGP expression in Dundoo cell cultures. |
In vitro propagation of Drosera intermedia in a single stepT. Grevenstuk, N. Coelho, S. Gonçalves, A. RomanoBiologia plantarum 54:391-394, 2010 | DOI: 10.1007/s10535-010-0071-6 A simple and efficient protocol for the micropropagation of Drosera intermedia, using cultures initiated from in vitro produced seedlings, is described. Shoot proliferation was significantly influenced by Murashige and Skoog (MS) macronutrient concentration, showing higher multiplication rates for 1/4 MS (the lowest concentration), but was not affected by the addition of 0.1 mg dm-3 kinetin. In all cases a multiplication percentage above 90 % was recorded. High rooting percentages (up to 100 %) were obtained in multiplication phase on 1/4 MS medium without growth regulators. In average 15.8 plantlets per initial shoot was produced after 8 weeks of culture. All plantlets were successfully acclimatized to ex vitro conditions, exhibiting normal development. |
Exogenously-supplied trehalose protects thylakoid membranes of winter wheat from heat-induced damageY. Luo, F. Li, G. P. Wang, X. H. Yang, W. WangBiologia plantarum 54:495-501, 2010 | DOI: 10.1007/s10535-010-0087-y The effects of trehalose pretreatment on thylakoid membranes of winter wheat were investigated under heat stress. Under normal growth conditions, the winter wheat synthesized 502 μg g-1(f.m.) trehalose, which increased to 1250 μg g-1(f.m.) under heat stress and to 1658 μg g-1(f.m.) in trehalose-pretreated seedlings. Under heat stress, proteins in the thylakoid membranes and the photosynthetic capacity were protected by trehalose pretreatment. Moreover, the electrolyte leakage, contents of malondialdehyde, superoxide anion and hydrogen peroxide, and lipoxygenase activity in trehalose-pretreated seedlings were lower than in the non-pretreated plants. |
The influence of sulfur limitation on expression levels of an o-acetylserine (thiol) lyase gene cloned from Vicia sativaA. U. Novero, R. FordBiologia plantarum 54:579-582, 2010 | DOI: 10.1007/s10535-010-0104-1 The o-acetylserine (thiol) lyase (OAS-TL) gene is part of the plant sulfate assimilation pathway. The synthesis of cysteine, the first product of the pathway containing organic sulfur, has been previously observed to be dependent on the availability of sulfur and activity of OAS-TL. In this study, the ability of Vicia sativa L. to alter its metabolism to compensate for deficiencies brought about by sulfur stress was utilized to elucidate the functionality of Voas-tl5 (GenBank Accession No. DQ456491), a gene cloned from Vicia sativa. The transcription levels of Voas-tl5 increased in response to sulfur deficiency, indicating that the gene was active in the cysteine biosynthetic pathway. |
Salicylic acid increased aldose reductase activity and sorbitol accumulation in tomato plants under salt stressI. Tari, G. Kiss, A. K. Deér, J. Csiszár, L. Erdei, Á. Gallé, K. Gémes, F. Horváth, P. Poór, Á. Szepesi, L. M. SimonBiologia plantarum 54:677-683, 2010 | DOI: 10.1007/s10535-010-0120-1 Increased aldose reductase (ALR) activities were detected in the leaf tissues of tomato plants grown for 3 weeks in culture medium containing 10-7 or 10-4 M salicylic acid (SA), and in the roots after the 10-4 M SA pretreatment. The ALR activity changed in parallel with the sorbitol content in the leaves of the SA-treated plants. Salt stress elicited by 100 mM NaCl enhanced the accumulation of sorbitol in the leaves of control plants and as compared with the untreated control the sorbitol content in the SA-pretreated leaves remained elevated under salt stress. DEAE cellulose anionexchange column purification of the protein precipitated with 80 % (NH4)2SO4 revealed two enzyme fractions with ALR activity in both the leaf and the root tissues. The fraction of the leaf extract that was not bound to the column reacted with glucose and glucose-6-P as substrates, whereas glucose was not a substrate for the bound fraction or for root isoenzymes. The root enzyme was less sensitive to salt treatment: 50 mM NaCl caused 30 % inhibition in the leaf extract, whereas the enzyme activity of the root extract was not affected. It is suggested that increased ALR activity and sorbitol synthesis in the leaves of SA-treated tomato plants may result in an improved salt stress tolerance. |
Citrate transporters play an important role in regulating aluminum-induced citrate secretion in Glycine maxJ. F. You, N. N. Hou, M. Y. Xu, H. M. Zhang, Z. M. YangBiologia plantarum 54:766-768, 2010 | DOI: 10.1007/s10535-010-0138-4 To further understand the process of Al-induced citrate secretion from soybean roots, the effect of protein synthesis inhibitor, anion channel blockers, and citrate carrier inhibitors on Al-induced citrate exudation was investigated in Al-resistant soybean cultivar PI 416937. Citrate exudation from roots increased with the increase of Al concentration from 10 to 50 μM and initiated after 4 h of Al exposure. Protein synthesis inhibitor, cycloheximide (CHM; 25 μM) completely inhibited Al-induced citrate secretion during 12-h exposure, suggesting that novel protein synthesis was necessary in Al-induced citrate efflux. Also both anion channel blocker anthracene-9-carboxylic acid (A-9-C) and citrate carrier inhibitor mersalyl acid (Mersalyl) significantly reduced citrate secretion, suggesting that both anion channels in plasma membrane and citrate carriers in mitochondria membrane were the rate limiting factors of Al dependent citrate release. However, Al-induced citrate secretion was insensitive to anion channel blockers phenylglyoxal (PG), 4,4'-diisothiocyanostibene-2,2'-disulfonat (DIDS) and citrate carrier inhibitor pyridoxal 5'-P (PP). |
Morphogenetic routes of long-term embryogenic callus culture of Areca catechuH. C. Wang, J. T. Chen, W. C. ChangBiologia plantarum 54:1-5, 2010 | DOI: 10.1007/s10535-010-0001-7 Early morphogenetic events and repetitive embryogenesis from callus culture of betel nut palm (Areca catechu L.) were studied using scanning electron microscopy. On Murashige and Skoog (MS) medium supplemented with 2 mg dm-3 dicamba, callus culture has capacity to form plantlets via somatic embryogenesis and to form secondary embryos for about 4 years. However, various abnormal embryos without differentiation of the leaf sheath and shoot apical meristem were observed, which showed bell-shaped and then cup-shaped or mushroom-shaped structures. These abnormal embryos contained distinctive structures, including a disk-shape interior region, surfaces with grooves and a stalk-like posterior region. During subculture, these abnormal embryos enlarged, became deformed and gradually lose their shape and then converted into nodular, compact embryogenic callus. It was also found that secondary embryos originated from interior surfaces or posterior regions of abnormal embryos, and gave rise to the next cycle of normal and abnormal embryos. |
Over-expression of heat shock protein gene hsp26 in Arabidopsis thaliana enhances heat toleranceY. Xue, R. Peng, A. Xiong, X. Li, D. Zha, Q. YaoBiologia plantarum 54:105-111, 2010 | DOI: 10.1007/s10535-010-0015-1 In the yeast Saccharomyces cerevisiae, the molecular chaperone HSP26 has the remarkable ability to sense increases in temperature directly and can switch from an inactive to a chaperone-active state. In this report, we analyzed the effect of expression of HSP26 in Arabidopsis thaliana plants and their response to high temperature stress. The hsp26 transgenic plants exhibited stronger growth than wild type plants at 45 °C for 16 h. The chlorophyll content and chlorophyll fluorescence decreased much more in wild type than in transgenic plants. Moreover, the transgenic plants had higher proline and soluble sugar contents, and lower relative electrical conductivity and malondialdehyde contents after high temperature stress. Furthermore, we found that over-expression of HSP26 in Arabidopsis increased the amount of free proline, elevated the expression of proline biosynthetic pathway genes and therefore enhanced Arabidopsis tolerance to heat stress. |
Cytomixis and associated meiotic abnormalities affecting pollen fertility in Clematis orientalisP. Kumar, V. K. Singhal, D. Kaur, S. KaurBiologia plantarum 54:181-184, 2010 | DOI: 10.1007/s10535-010-0031-1 Present cytological investigations from the cold desert regions of Lahaul-Spiti and Kinnaur (India) record the first ever tetraploid (2n=32) chromosome count and cytomixis in Clematis orientalis L. var. acutifolia Hook. f. et Thoms. The phenomenon of cytomixis (9.33-29.80 %) involving chromatin transfer among 2-3 proximate pollen mother cells (PMCs) during male meiosis occurs through narrow and broad cytoplasmic channels from early prophase to tetrad stage. However, frequency of its occurrence during the later meiotic stages is rather low. Chromatin transfer results into the formation of hypo-, hyperploid and enucleated PMCs. Various meiotic abnormalities associated with cytomixis such as chromatin stickiness, pycnotic chromatin, interbivalent connections, out of plate bivalents, late disjunction of bivalents, and laggards and bridges resulted into some pollen sterility (16.33-49.30 %) and heterogeneous pollen grains size. |
Influence of water stress on photosynthetic characteristics in barley plants under ambient and elevated CO2 concentrationsA. Robredo, U. Pérez-López, M. Lacuesta, A. Mena-Petite, A. Muñoz-RuedaBiologia plantarum 54:285-292, 2010 | DOI: 10.1007/s10535-010-0050-y We evaluated the combined effects of elevated CO2 and water availability on photosynthesis in barley. Soil and plant water content decreased with water stress, but less under elevated CO2 concentration (EC) compared with ambient CO2 concentration (AC). During water stress, stomatal conductance, carboxylation rate, RuBP regeneration, and the rate of triose phosphate utilisation (TPU) were decreased but less when plants grew under EC. Drought treatments caused only a slight effect on maximum photochemical efficiency (variable to maximum fluorescence ratio, Fv/Fm), whereas the actual quantum yield (ΦPS2), maximum electron transport rate (Jmax) and photochemical quenching (qP) were decreased and the non photochemical quenching (NPQ) was enhanced. Under water deficit, the allocation of electrons to CO2 assimilation was diminished by 49 % at AC and by 26 % at EC while the allocation to O2 reduction was increased by 15 % at AC and by 12 % at EC. |


