Eukaryotic elongation factor Tu has been implicated in responses to heat stress and viral infection. In this study, the turnip mosaic virus (TuMV)-response gene BcLRK01, which encodes a leucine-rich repeat receptor-like kinase, was probed using the cDNA library of TuMV-infected leaves of non-heading Chinese cabbage (Brassica campestris ssp. chinensis). The BcEF-Tu gene, which encodes chloroplast elongation factor Tu, was obtained and verified by a yeast two-hybrid system to interact with the BcLRK01 gene. TuMV infection depressed the expression of this gene, whereas a heat stress induced its expression. Overexpression of BcEF-Tu enhanced the viability of Escherichia coli transformants under the heat stress. These results demonstrate that elongation factor BcEF-Tu responded to the TuMV infection and heat stress. This is the first report on chloroplast EF-Tu in non-heading Chinese cabbage which provides a theoretical basis for the functional research of EF-Tu.

The roles of ascorbic acid (AsA, 1 mM) under an osmotic stress [induced by 15 % (m/v) polyethylene glycol, PEG-6000] were investigated by examining morphological and physiological attributes in Brassica species. The osmotic stress reduced the fresh and dry masses, leaf relative water content (RWC), and chlorophyll (Chl) content, whereas increased the proline (Pro), malondialdehyde (MDA), and H₂O₂ content, and lipoxygenase (LOX) activity. The ascorbate content in B. napus, B. campestris, and B. juncea decreased, increased, and remained unaltered, respectively. The dehydroascorbate (DHA) content increased only in B. napus. The AsA/DHA ratio was reduced by the osmotic stress in all the species except B. juncea. The osmotic stress increased the glutathione (GSH) content only in B. juncea, but increased the glutathione disulfide (GSSG) content and decreased the GSH/GSSG ratio in all the species. The osmotic stress increased the activities of ascorbate peroxidase (APX) (except in B. napus), glutathione reductase (GR) (except in B. napus), glutathione S-transferase (GST) (except in B. juncea), and glutathione peroxidase (GPX), and decreased the activities of catalase (CAT) and monodehydroascorbate reductase (MDHAR) (only in B. campestris). The osmotic stress decreased the glyoxalase I (Gly I) and increased glyoxalase II (Gly II) activities. The application of AsA in combination with PEG improved the fresh mass, RWC, and Chl content, whereas decreased the Pro, MDA, and H₂O₂ content in comparison with PEG alone. The AsA addition improved AsA-GSH cycle components and improved the activities of all antioxidant and glyoxalase enzymes in most of the cases. So, exogenous AsA improved physiological adaptation and alleviated oxidative damage under the osmotic stress by improving the antioxidant and glyoxalase systems. According to measured parameters, B. juncea can be recognized as more drought tolerant than B. napus and B. campestris.

Plant growth regulators (PRG)-assisted phytoremediation is a technique that could enhance the yield of heavy metal accumulation in plant tissues. So far, a small number of experiments have helped identify three groups of plant hormones that may be useful for this purpose: auxins, cytokinins, and gibberellins. Studies have shown that these hormones positively affect the degree of accumulation of metallic impurities and improve the growth and stress resistance of plants. This review summarizes the present knowledge about PGRs' impact on phytoextraction yield.

In suspension cell cultures of Silybum marianum, methyl jasmonate (MJ) stimulated the accumulation and release of silymarin (Sm) to the culture medium. This study shows that phospholipase A2 (PLA2) plays a role in the release of Sm in elicited cultures. PLA2 activity increased in cell suspensions treated with MJ. Addition of aristolochic acid (AA) or bromoenol lactone (BEL) compounds that inhibit PLA2 activity impeded silymarin release. The addition of linoleic or linolenic acid reversed the inhibitory action of AA. Fatty acids (FAs) stimulated Sm release when added alone to control cultures. By contrast, oleic acid and saturated FA were ineffective in emulating MJ action.

The effects of abiotic stresses on the expression of Lhcb1 gene (coding light-harvesting chlorophyll-protein complex II), and on photosynthetic rate were studied in one Oenanthe javanica (cv. Baguazhou Shuiqin) and three Apium graveolens cultivars (Liuhe Huangxinqin, Jinnan Shiqin, and Ventura). The Lhcb1 genes were cloned and we predicted that Lhcb1 proteins were most probably able to form homo-trimers. Each monomer contained five helical segments, of which three were likely transmembrane helices, and 15 putative chlorophyll-binding sites. The abiotic stresses affected the A. graveolens similarly in all the cultivars, however, the O. javanica photosynthesis was not significantly affected. The expression of the Lhcb1 gene was up-regulated under the cold, heat, salt, and drought stresses in the cvs Liuhe Huangxinqin and Jinnan Shiqin. The Lhcb1 was up-regulated under the heat, salt, and drought stresses in the cv. Ventura, whereas had no significant changes under the cold stress. No significant changes of the Lhcb1 expression were found under the cold and salt stresses and even little down-regulation following the heat and drought stresses in Oenanthe javanica. The expression of Lhcb1 may be a useful indicator of photosynthetic activity.

Feverfew (Tanacetum parthenium) is a medicinal plant belonging to the Asteraceae family. To improve understanding terpene metabolism in feverfew, the relative gene expression of four key genes coding 3-hydroxy-3-methylglutarylcoenzyme A reductase (HMGR) and germacrene A synthase (GAS) from the mevalonic acid pathway (MVA), as well as 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) and hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase (HDR) from the methyl erythritol phosphate pathway (MEP), were examined. Target organs and tissues included young leaves (not fully expanded), mature leaves (fully expanded), flowers, stems, roots, and glandular trichomes. HMGR, DXR, and HDR were isolated and sequenced for the first time in feverfew. Real-time quantitative PCR analysis revealed differential expression of these genes in feverfew tissues and developmental stages.

High summer temperature negatively affects cotton yield, and better understanding of genetic mechanisms of heat stress responses in cotton may facilitate development of new heat tolerant cultivars. We attempted to determine heat responsive genes in cotton using tolerant (Stoneville 453, BA 119) and susceptible (Nazilli 84S) cultivars. Twenty five expressed sequence tags (ESTs) were sequenced and studied for gene homology. Sixteen ESTs were significantly similar to known genes, whereas eight ESTs were similar to not annotated cDNA clones and 1 EST did not show homology to any known gene. Expression of some ESTs was analyzed by quantitative real-time PCR and IAA-ala hydrolase (IAR3), folylpolyglutamate synthase (FPGS3), and two not annotated ESTs (GhHS126 and GhHS128) were consistently up-regulated under both short- and long-term heat stress. Since cotton is considered relatively more heat tolerant than most of the other crops, it can be suggested that these genes and ESTs could play a significant role in heat tolerance. In addition, GhHS126 and GhHS128 might be parts of the new candidate genes for heat tolerance.

Exposure to low temperatures is one of the most important factors that generate abiotic stress in plants, and the rapid accumulation of soluble sugars belongs to significant metabolic responses to cold stress. The accumulation of soluble sugars may be at least partially triggered by an increased rate of starch degradation. The analysis of transcript profiles and starch degrading enzyme activities in leaves of two potato cultivars was performed during a 12-h exposure to 2 °C. An induction of β-amylase expression and activity as well as an accumulation of reducing sugars were observed in cv. Desiree. No accumulation of reducing sugars and no significant changes in the β-amylase activity were initially observed in cv. Russet Burbank. Surprisingly, an increased α-amylase activity was observed in the last hours of the experiment, which was accompanied by an increased amount of reducing sugars. The results indicate that the leaves of Desiree and Russet Burbank potatoes growing under cold stress may degrade starch via different pathways.

We employed the comet assay (single cell gel electrophoresis) to evaluate induced DNA damage in nuclei isolated from tobacco leaves (Nicotiana tabacum var. xanthi) inoculated with Potato virus X (PVX). The highest DNA damage, expressed by the tail moment value, was observed in the inoculated leaves and decreased in the 1^st to 4^th systemic leaves. DNA damage increased with the time after the inoculation (from day 3 to day 21) and was higher in nuclei isolated from a part of the leaf at the petiole compared to nuclei isolated from the leaf tip. A Pearson moment correlation (r = 0.94) between the induced DNA damage and the PVX titres expressed by ELISA absorbance values was observed. The PVX infection did not induce a significant increase in the rate of somatic mutations evaluated by appearance of dark green, yellow, and double green/yellow sectors on the heterozygous pale green leaves of N. tabacum var. xanthi.

A gene encoding Mn-containing superoxide dismutase (Mn-SOD), designated as ThMSD, was cloned from salt cress (Eutrema halophilum) by reverse transcriptase - polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The full length of ThMSD (acc. No. EF413171) is 1 047 bp with an open reading frame (ORF) of 693 bp. The deduced 231-amino acid polypeptide had a predicted molecular mass of 25.5 kDa, an estimated pI of 9.08, and a putative Mn-binding site. Recombinant ThMSD protein was expressed in Escherichia coli and characterized. The SOD activity of ThMSD was inactivated by sodium azide but not by potassium cyanide or hydrogen peroxide confirming that ThMSD is a Mn-SOD. Real-time PCR revealed that ThMSD was expressed in roots, rosette leaves, stems, stem leaves, flowers, and siliques. ThMSD mRNA reached the highest content in roots and its content increased when plants were treated with NaCl (in a concentration dependent manner), ABA, and subjected to drought. ThMSD was transformed into Arabidopsis and the stress tolerance properties of transgenic lines were assayed. The seeds of transgenic lines exhibited significantly higher germination rate under 100 and 150 mM NaCl than the wild type. The root growth of transgenic lines was affected less obviously than the wild type under 100 mM NaCl. The above results indicate that ThMSD played an important role in E. halophilum tolerance to environmental stresses, especially NaCl stress.

Extracellular proteins and glycoproteins secreted by ammonium- or auxin-induced somatic embryogenic cultures of pumpkin were analyzed. Despite an overall similarity in developmental characteristics between these embryogenic cultures, distinct expression patterns of extracellular proteins and glycoproteins were observed. Ammonium, when supplied as the sole source of nitrogen, caused acidification of the culture medium and significantly reduced protein secretion. Buffering pH in the ammonium-containing medium restored extracellular protein secretion and glycosylation and an enhanced cell aggregation but not the development of later embryo stages. As revealed by Concavalin A (Con A) immunodetection, extracellular glycoproteins containing α-D-mannose and α-D-glucose were most abundant in proembryogenic cultures grown in a buffered ammonium-containing medium and in a medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D). We assume that extracellular proteins (Mr 28, 31, and 44 kDa) and Con Abinding glycoproteins (Mr 26, 30, 40, 53, and 100 kDa) found in both proembryogenic cultures may have a role during somatic embryogenesis induction. The glycan components of proteins were further characterized by affinity blotting with different lectins. Binding patterns of mannose-specific lectin from Galanthus nivalis partially correlated with those detected with Con A, whereas no signal was observed with lectins from Datura stramonium and Arachis hypogea regardless of the treatment applied. Results indicate that complex N- or O-glycans are not typical for early phases of pumpkin embryo development. The accumulation of extracellular glycoproteins with high-mannose-type glycans from 30 to 34 kDa, observed after the transfer from the ammonium- or 2,4-D-containing media into a maturation medium, appeared to be associated with development of later embryo stages. This study also revealed the presence of EP-3-like endochitinases in pumpkin embryogenic cultures, particularly in cultures grown in the buffered ammonium-containing medium, however, these proteins should be examined further.

Polyunsaturated fatty acids (PUFAs) affect diverse physiological processes and human health. Most cereals are poor in n-3 and n-6 PUFAs. Using biolistics, barley (Hordeum vulgare L. cv. Golden Promise) was transformed with an artificial gene encoding Δ⁶-desaturase (D6D) under an endosperm-specific promoter. This artificial gene was designed from the sequence of D6D of the filamentous fungus Thamnidium elegans, but codon usage was optimised for cereals. A signal sequence from the gene encoding for high molecular mass glutenin Dx5 was added to a destinate mature protein. Successful transformation was confirmed in T₀ plants at the genomic level and in T₁ seeds at the transcriptomic and metabolomic levels. Transformed plants produced up to 0.141 % of γ-linolenic acid (GLA) and 0.294 % of stearidonic acid (SDA) of the total amount of fatty acids in their grains. Although the content of these fatty acids was relatively low, the current study provides the first evidence that transgenic barley can be a source of GLA/SDA.

Cassava (Manihot esculenta Crantz) is an important crop and it is significantly affected by water stress. The computational analysis of cis-regulatory elements in promoter regions of 21 drought-responsive miRNA gene families and 35 miRNA-target genes in cassava indicated some elements relevant to drought stress responses. To investigate the role of miRNAs and target genes in responses to a water deficit in cassava in more detail, in vitro plantlets were subjected to an imitated water deficit by 40 % polyethylene glycol. Using RT-qPCR, the differential expression of the cassava miR164/MesNAC and miR167/MesARF6/8 were observed to be associated with changes in the leaf shape, stomatal closure, and relative water content. The modified 5'-RNA ligase-mediated rapid amplification of cDNA-end (5'RLM-RACE) experiment confirmed MesNAC and MesARF8 as the in vivo-target genes of miR164 and miR167, respectively, in cassava leaf. The possible functions of miR164 and miR167-target genes in response to water deficit are discussed.

Five in vitro culture systems with different ventilation rates were used to investigate the influence of vessel environment on photosynthesis, dark respiration, ethylene evolution, and rosmarinic acid (RA) production in sweet basil (Ocimum basilicum L.) micropropagated shoots. The systems under comparison were two bioreactors with either temporary (RITA™) or stationary (Growtek™) immersion, and three types of vessels (Magenta™, Microbox ECO ₂ ™, and PCCV25™) that are largely used for plant micropropagation. Shoots of green-leaved cv. Genovese and purple-leaved cv. Dark Opal were cultured on a modified Murashige and Skoog medium containing 0.25 mg dm^-3 6-benzylaminopurine. The instantaneous rates of photosynthesis, dark respiration, and ethylene production were determined by gas chromatography measuring CO₂ and ethylene concentrations in vessel headspaces. The tissue RA content was determined by HPLC in HCl-methanol extracts. The explant growth and morphology were significantly affected by culture conditions and cultivars. The largest biomass production was observed under the photomixotrophic culture conditions provided by Growtek™, whereas the highest RA content in shoot tissues was found in the RITA™ photomixotrophic system, where ethylene accumulated to the greatest extent.

Salt decreases the uptake of Zn and other minerals and causes nutritional disorders in plants. Zn is an essential micronutrient for all organisms and it is reasonable to hypothesize that Zn status is essential for maintaining salt tolerance in plants. In this study, the physiological and molecular mechanisms of Zn-based alleviation of salt stress in wheat seedlings were investigated. Our results indicate that sufficient Zn nutrition maintained antioxidative enzyme activities and decreased a reactive oxygen species over-accumulation in wheat seedlings. Our data also reveal that sufficient Zn nutrition improved the expression of Na⁺/H⁺ antiporter genes, TaSOS1 and TaNHX1, thereby decreasing the Na⁺ accumulation and subsequently improving salt tolerance in wheat seedlings.

Stems of angiosperm trees are affected by gravity. Young poplar stems show primary growth in the top internodes and differential cambium activity in the basal internodes after inclination with some tension wood formed after 45 min. This study was conducted in order to characterize the early changes in poplar gene expression during the early stages of the gravitropic response. Using microarray technology, the expression of 15 000 genes was examined. Approximately 3.1 % of these genes exhibited significant expression changes within the first 45 min of gravity stimulation. Approximately 73 % of the identified genes were found to have a known or predicted molecular function. Many of these genes were involved in secondary wall formation (cellulose synthesis and lignification), cytoskeleton development, signaling, and stress response. Some identified genes seem to play a role in sensing gravitational signals during tension wood formation. A large number of the identified arabinogalactan (AGP) and transcription factor genes were involved in cell wall biosynthesis suggesting that these genes are particularly active in the first phases of signal transduction during tension wood formation.

Self-grafted and pumpkin rootstock-grafted cucumber plants were subjected to the following four treatments: 1) aerated nutrient solution alone (control), 2) nutrient solution with 10 mM Ca(NO₃)₂ (Ca), 3) nutrient solution with 90 mM NaCl (NaCl), and 4) nutrient solution with 90 mM NaCl + 10 mM Ca(NO₃)₂ (NaCl+Ca). The NaCl treatment decreased the plant dry mass and content of Ca²⁺ and K⁺ but increased the Na⁺ content in roots and shoots. Smaller changes were observed in pumpkin rootstock-grafted plants. Supplementary Ca(NO₃)₂ ameliorated the negative effects of NaCl on plant dry mass, relative growth rate (RGR), as well as Ca²⁺, K⁺, and Na⁺ content especially for pumpkin rootstock-grafted plants. Supplementary Ca(NO₃)₂ distinctly stimulated the plasma membrane (PM) H⁺-ATPase activity which supplies the energy to remove excess Na⁺ from the cells. The expressions of gene encoding PM H⁺-ATPases (PMA) and gene encoding a PM Na⁺/H⁺ antiporter (SOS1) were up-regulated when Ca(NO₃)₂ was applied. The pumpkin rootstock-grafted plants had higher PM H⁺-ATPase activity as well as higher PMA and SOS1 expressions than the self-grafted plants under NaCl + Ca treatment. Therefore, the addition of Ca²⁺ in combination with pumpkin rootstock grafting is a powerful way to increase cucumber salt tolerance.

This study was carried out to better understand the role of 24-epibrassinolide (EBR) in thermotolerance of melon (Cucumis melo L.). The melon seedlings were pretreated with various concentrations of EBR (0, 0.05, 0.1, 0.5, 1.0, and 1.5 mg dm^-3) as foliar spray and then exposed to a high temperature (HT) stress. Exogenous EBR (0.5-1.5 mg dm^-3) alleviated HT-caused growth suppression. In parallel, 1.0 mg dm^-3 EBR attenuated the decrease in chlorophyll content, net photosynthetic rate, stomatal conductance, maximum quantum efficiency of photosystem (PS) II, quantum yield of PS II, and photochemical quenching of chlorophyll a fluorescence in HT-stressed plants, and inhibited transpiration rate and non-photochemical quenching. Furthermore, exogenous EBR also significantly reduced the content of malondialdehyde (MDA) and increased the content of soluble proteins and free proline, and activities of antioxidant enzymes including superoxide dismutase, guaiacol peroxidase, catalase, and ascorbate peroxidase under the HT stress. The results show that protective effects of EBR against the HT stress in the melon seedlings were most likely mediated through the improvement of photosynthesis and the stimulation of antioxidant capacity.

VERNALIZATION INSENSITIVE 3 (VIN3) is a chromatin remodelling protein that is induced by low temperatures and is required for the vernalization response in Arabidopsis thaliana. VIN3 is one of the polycomb group (PcG) proteins, which mediates epigenetic repression of FLOWERING LOCUS C (FLC) in A. thaliana. Here, we present cloning, characterization, and expression of a putative SlVIN3 gene in tomato (Solanum lycopersicum L.) by isolating cDNA clones corresponding to SlVIN3 gene using primers designed based on conserved sequences between PcG genes in A. thaliana and tomato. The SlVIN3 cDNAs were cloned into a pBS plasmid and sequenced. Both 5' and 3' RACE were generated and sequenced. The flcDNA of 2 823 bp length for the SlVIN3 gene was composed of 5'UTR (336 bp), ORF (2 217 bp), and 3'UTR (270 bp). The translated ORF encoded a polypeptide of 739 amino acids. Alignment of deduced amino acids indicates that there are highly conserved regions between tomato SlVIN3 predicted protein and plant VIN3 gene family members. Both unrooted phylogenetic trees constructed using the maximum parsimony and maximum likelihood methods indicate that there is a close relationship between SlVIN3 predicted protein and VIN3 protein of Vitis vinifera. The expression of SlVIN3 gene remained high during floral organ differentiation and growth and decreased when the fruit started to develop.

The MYB, MYC, and WD40 transcription factors (TFs) are known to regulate the expression of structural biosynthetic genes at different steps depending on the plant species. In this work, we used an agroinfiltration protocol with Tobacco rattle virus (TRV) constructs containing partial sequences from MYB or WD40 for virus-induced gene silencing (VIGS) to demonstrate their participation in the regulation of anthocyanin biosynthesis in chilli pepper (Capsicum eximium) fruits. The accumulation of anthocyanins in chilli pepper fruits of plants transformed with TRV2-MYB and TRV2-WD40 constructs was significantly reduced compared to the control or empty TRV2-transformed plants. A significant reduction in gene expression of both TFs was also detected. The expressions of the chalcone synthase (CHS), chalcone isomerase (CHI), flavonoid 3',5'-hydroxylase (F3'5'H), dihydroflavonol 4-reductase (DFR), and UDP-glucose:flavonoid 3-O-glucosyltransferase (3GT) genes were decreased in the plants transformed with the TRV2-MYB construct but not the transcription of flavanone 3-hydroxylase (F3H). When chilli pepper plants were infected with the TRV2-WD40 construct, a significant reduction in CHS, F3H, F3'5'H, DFR and 3GT expression, but not in CHI in the fruits was observed.

The effects of NiSO₄, calcium, and L-histidine (His) on the components of ascorbate-glutathione cycle, antioxidant enzymes and lipid peroxidation in a tomato cultivar Early Urbana Y was investigated. The activities of enzymes including catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR), lipoxygenase (LOX), and phenylalanine ammonia lyase (PAL) were measured. In addition, the content of H₂O₂, ascorbate (ASC), dehydroascorbate (DHA), reduced glutathione (GSH), chlorophyll (Chl) a+b, carotenoids, proteins, malondialdehyde (MDA), membrane aldehydes, and electrolyte leakage (EL) were determined. Results suggest that the excess of Ni increased the content of H₂O₂, MDA, membrane aldehydes and proteins in roots as well as GPX, LOX, APX activities, and EL in leaves, whereas Ca and His ameliorated these effects. Moreover, decreasing leaf GSH and DHA content and GR activity were observed under the Ni stress, but these parameters were raised by Ca plus His treatment. However, no improvement in leaf protein, ASC, root GSH content, and activities of PAL and CAT were observed by using Ca or His under Ni stress.

Candidate Arabidopsis thaliana S-domain receptor-like kinase (SD-RLK) (At1g11330, At1g61430, and At1g61610) and leucine-rich repeat receptor-like kinase (LRR-RLK) (At1g51850, At2g19190, and At5g45840) genes were characterized utilizing PlantPAN, AGRIS, and AthaMap databases. Following determination of the main conserved domains, both classes of RLKs were found to be structurally similar with extracellular, transmembrane, and intracellular domains including a serine/threonine kinase domain, which might suggest a functional role in intracellular signal transduction. This established that the RLK genes had a superficially similar structure but distinct ligand binding domains. The expressions of these genes in response to a treatment with microbe-associated molecular pattern molecules (MAMPs), namely lipopolysaccharides, flg22 peptide from flagellin, peptidoglycan, chitosan, and ergosterol were compared. The candidate RLKs, potentially involved in surveillance, were found to be responsive to the elicitation treatments. Furthermore, differential regulation that was observed at the transcriptional level as well as the intensity of responses could possibly be correlated to the promoter architecture. With the use of in silico analyses, the architectures of 1 000 bp promoter regions upstream from the transcription start sites were determined. The analyses also revealed putative defense-related cis-regulatory elements that included W-boxes, MYB factor, AP2/ERF-, GT1- and ATHB-5 binding sites. The frequency at which these cis-elements occurred in each promoter differed, and the number or clusters within the core-regulatory region of individual promoters might be indicative of the responsiveness of each gene to the MAMP elicitation.

Chili pepper (Capsicum annuum L.) cv. Árbol and Uvilla fruits differing in anthocyanin contents were analyzed to characterize the accumulation patterns. The maximum accumulation of the aglycon delphinidin occurred 20 days postanthesis (DPA) with higher content in Uvilla than in Árbol fruits. Regarding the cDNA library, 9 186 cDNA clones were selected. The clones with high homology to genes concerning anthocyanin biosynthesis, such as encoding chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonoid 3',5'-hydroxylase (F3'5'H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), UDP Glc-flavonoid 3-O-gluco-syl transferase (UFGT), and also those possibly involved in anthocyanin transport into the vacuoles, an anthocyanin permease (ANP) and a glutathione S-transferase (GST) were used for gene expression analysis. In general, the expression of all investigated genes was developmentally regulated in both Árbol and Uvilla. CHS and CHI transcripts were expressed at the maximal level at 10 DPA, and then consistently declined throughout fruit development. F3'5'H, DFR, UFGT and GST expression exhibited a positive correlation with anthocyanin accumulation, and the highest transcript levels were detected prior to or by the time of maximum anthocyanin accumulation, depending on the chili pepper type. Pericarp fruit tissues from cv. Tampiqueño 74, an anthocyanin non-accumulator, also showed CHS, CHI, F3H, ANS and ANP expression at some developmental stages.

We investigated the role of 24-epibrassinolide (EBR) in the amelioration of phenanthrene (PHE) stress in tomato (Solanum lycopersicum L.). Exposure to PHE (300 μM) significantly decreased shoot and root length (19 and 16 %, respectively), fresh mass (35 and 43 %, respectively), contents of chlorophyll a (26 %), chlorophyll b (27 %) and carotenoids (18 %) in tomato plants. In addition, PHE increased the malondialdehyde (MDA) content (57 %) and activity of secondary metabolism related enzymes glutathione-S-transferase (GST), glucose-6-phosphate dehydrogenase (G6PDH), shikimate dehydrogenase (SKDH), phenylalanine ammonia-lyase (PAL) and cinnamyl alcohol dehydrogenase (CAD). The expression levels of GST1, PPO, SKDH, PAL and CAD genes were also induced by PHE. Importantly, EBR (0.1 μM) alone and in combination with PHE increased the growth, biomass and activity of those enzymes significantly over control and PHE alone, respectively. Consistent with enzymes activities transcript levels of GST1, PPO, SKDH, PAL and CAD were further increased in PHE+EBR over PHE alone. However, MDA content was remarkably decreased in PHE+EBR than PHE alone. Meanwhile, content of phenols, flavonoids and antioxidant activity were increased by PHE and PHE+EBR further increased all those parameters. These observations suggest that EBR regulates secondary metabolism in tomato which might enhance tolerance to PHE.

Actin is the most abundant protein in eukaryotic cells and is a key cytoskeletal component controlling cell morphology and motility. In this study, four MiACT genes were isolated from mango by homological cloning and designated as MiACT1, MiACT4, MiACT7, and MiACT9. Sequence alignments and phylogenetic analysis demonstrated that the four MiACT genes of mango were highly similar to each other at the nucleotide and amino acid levels. All of four MiACT proteins showed high similarity to the known actin proteins from other species. Reverse transcription polymerase chain reaction revealed that the four MiACT genes were constitutively and stably expressed in all organs tested. Application of plant growth regulators and four stress treatments had a remarkable effect on the expression of MiACT4, MiACT7 and MiACT9, whereas expression of MiACT1 was unresponsive. In contrast, the expression profiles of the four MiACT genes were not regulated by diurnal rhythms. Moreover, the expression of MiACT1 was not affected by heavy metal treatments and the transcript level of MiACT1 was rather stable in different days during the post-harvest period either under treatment or not. Our results suggest that the four actin genes play important roles throughout the entire life cycle of mango; the constitutively and stably expressed MiACT1 is the best candidate as an internal standard for differential gene expression analysis in mango.

Two wheat (Triticum aestivum L.) genotypes with varying degree of drought tolerance were used to analyze programmed cell death (PCD) and related biochemical changes under drought stress. Drought induced PCD in leaves, as evident by internucleosomal nDNA fragmentation, was observed in sensitive genotype Nesser. Drought tolerant genotype (FD-83) showed higher peroxidase, superoxide dismutase, and catalase activities and ascorbate content under drought stress compared to sensitive genotype. Total phenolic content increased whereas lipid peroxidation remained un-changed under drought in FD-83. In contrast, drought enhanced the proteases and ascorbate peroxidase activities and lipid peroxidation (MDA content) in Nesser.

Organic acid (OA) metabolisms are of fundamental importance but very limited data are available on the responses of plant OA metabolisms to Mg-deficiency. Seedlings of Citrus sinensis (L.) Osbeck cv. Xuegan were irrigated with Mg-deficient (0, 50, or 500 μM MgSO₄) or Mg-sufficient (2000 μM MgSO₄) nutrient solution every other day for 12 weeks. Thereafter, we investigated the content of Mg, malate, and citrate as well as the activities of acidmetabolizing enzymes in roots and leaves. Root malate content remained stable except for an increase in the highest Mg content and root citrate content increased with increasing root Mg content. As leaf Mg content increased, leaf malate and malate + citrate content decreased whereas leaf citrate content increased. Mg-deficiency decreased or did not affect activities of citrate synthase (CS), aconitase (ACO), phosphoenolpyruvate carboxylase (PEPC), NADP-isocitrate dehydrogenase (NADP-IDH), NAD-malate dehydrogenase (NAD-MDH), NADP-malic enzyme (NADP-ME), and pyruvate kinase (PK) in roots, whereas phosphoenolpyruvate phosphatase (PEPP) activity slightly increased. In contrast, Mg-deficient leaves had higher or similar activities of enzymes above mentioned except PEPP, NAD-MDH, and NADP-ME. In conclusion, both glycolysis and tricarboxylic acid (TCA) cycle may be up-regulated in Mg-deficient leaves but down-regulated in Mg-deficient roots.

Cadmium is a widely spread pollutant and the objective of this study was to study the effects of different concentrations of Cd (0, 50, and 100 μM) on the soybean seedlings treated for 10 d. The growth was inhibited and chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, probability that a trapped exciton moves an electron into the electron transport chain beyond QA - (ET_O/TR_O), performance indexes (PI_ABS), and amount of active reaction centres per excited cross section (RC/CS_O) were decreased with the increasing Cd concentration. The leaf reflectance increased in visual range (500-670 nm) and decreased in near-infrared range (750-1 000 nm). The accumulation of Cd in the roots was much higher than that in the stems and leaves.

To examine whether ferulic acid (FA) could protect plants from dehydration stress and to investigate a mechanism for the protection, cucumber seedlings were pretreated with 0.5 mM FA for 2 d and then were exposed to dehydration induced by 10 % polyethylene glycol 6000. After pretreatment with FA, the activities of antioxidant enzymes (catalase, superoxide dismutase, and quaiacol peroxidase) in leaves were higher than under dehydration treatment alone which was in accordance with the increased transcript levels of respective genes. Moreover, the combination of FA pretreatment and dehydration reduced the content of superoxide radical, hydrogen peroxide, and malondialdehyde, and increased the relative water content and content of FA, proline, and soluble sugars in comparison with dehydration alone. We propose that pretreatment with FA protects cucumbers against dehydration stress by decrease of lipid peroxidation due to activation of antioxidant enzymes and by increase of proline and soluble sugar content in leaves.

The genetic diversity and ancestral relationships of a number of Trifolium species was revealed by using the amplified fragment length polymorphism (AFLP) and the random amplified polymorphic DNA (RAPD) markers. Both markers produced few species-specific markers. Using distance and parsimony methods, in NTSYS-pc and PAUP software programs, we clearly differentiated the accessions of white clover from other closely related progenitors. The phylogenetic trees, produced by PAUP, also reinforced the close affinity of T. nigrescens and the allopolyploid white clover in support of former views that this diploid species could have been the donor of one of two genomes of the allotetraploid T. repens. In addition, the dendrograms, produced by NTSYS-pc, also indicated close affinity of T. nigrescens and T. occidentale to the accessions of T. repens. These data is congruent with karyological and phylogenetic affinities between the white clover and T. occidentale. The relationships between the examined accessions, in the T. repens gene pool, may be regarded to indicate the presence of shared alleles between T. repens, T. occidentale and T. uniflorum. Further, T. occidentale showed close phylogenetic relations to T. pallescens.