With the dramatic increase in nanotechnologies, it has become probable that biological systems will be exposed to excess of nanoparticles (NPs). However, the impact of NPs on plants, remains to be explored. The aim of this research was to determine the effects of ZnO NPs on tomato (Solanum lycopersicum L.) plants. Plant growth, photosynthetic characteristics, chlorophyll fluorescence parameters, and activities of antioxidative enzymes were measured in 35-d-old plants. The ZnO NP treatments significantly inhibited tomato root and shoot growth, decreased the content of chlorophylls a and b, and reduced photosynthetic efficiency and some other chlorophyll fluorescence parameters in a concentration-dependent manner. However, the supernatant of ZnO NP suspensions did not affect growth of tomato, despite the presence of small amounts of Zn²⁺. Taken together, these results suggest that toxic effects on tomato plants were from ZnO NPs, not from Zn²⁺ released into the solution; toxicity was likely caused by reduced chlorophyll content and damaged photochemical system, which in turn limited photosynthesis and led to the reduction in biomass accumulation. Also, ZnO NPs enhanced the transcription of genes related to antioxidant capacity, suggesting that ZnO NPs could enhance the defence response by increasing activities of antioxidant enzymes.

To facilitate functional genomic analysis and molecular breeding of velvet ash (Fraxinus velutina Torr), the de novo sequencing was carried out by Illumina sequencing technology. The cDNA samples were prepared from eleven different tissues of velvet ash and sequenced by using the Illumina genome analyzer. Subsequently, de novo assemebly, functional annotation databases, and the screening of expressed sequence tag-simple sequence repeats (EST-SSRs) were performed by comparing with corresponding databases using BLASTx and software tools. We obtained 51 698 unigenes with an average length of 661 bp and an N50 length of 980 bp. Among all these unigenes, 41 267 (79.8 %) were annotated in the NCBI non-redundant protein database and 25 236 (48.8 %) were annotated in the Swiss-Prot database. A total of 31 546 (61.0 %) and 13 281 (25.7 %) unigenes were successfully categorized to 59 and 25 functional groups, respectively, by gene ontology categories and clusters of orthologous group categories. A total of 22 323 (43.2 %) unigenes were assigned to 128 pathways using the Kyoto encyclopedia of genes and genomes pathway database. Additionally, 3 249 EST-SSRs markers were detected in 51 698 unigenes from velvet ash. Based on 3 249 EST-SSRs markers, 1 800 primer pairs were successfully designed using Primer 3. In the 50 randomly selected primers, 48 successfully amplified fragments, and 42 showed polymorphisms. We completed a successful application of the Illumina platform to de novo transcriptome assembly of velvet ash, which has the potential to be used for discovering novel genes and further characterization of gene expression profiles.

Rice (Oryza sativa L.) is a salt-sensitive species. Salt stress can cause injury to the plant cellular membrane. Plant lipid transfer proteins (LTPs) are abundant lipid binding proteins that are important in membrane vesicle biogenesis and trafficking, however, the biological importance of LTPs on salt-stress response in rice remains unclear. Therefore, salt-responsive rice LTPs were identified and characterized in this study. Microarray analysis showed seven genes positively regulated by salinity, including five Ltp genes (LtpII.3, LtpII.5, LtpII.6, LtpV.1, and LtpV.2) and two Ltp-like (LtpL; LtpL1, and LtpL2) genes. Amino acid alignment revealed that all these Ltp and LtpL genes contained the N-terminal signal peptide. Apart from LtpL1, all salt-inducible Ltp genes had the conserved eight cysteine residue motifs backbone. Verification of gene expression to different stimuli in rice seedlings revealed that salt-regulated Ltp genes differentially responded to drought, cold, H₂O₂, abscisic acid (ABA) and CaCl₂. Furthermore, the expression of Ltp and LtpL genes was tissue-specifically regulated by ABA-dependent and independent pathway. In silico analysis of a 1.5-kb 5'-upstream region of these genes showed regulatory cis-elements associated with ABA, calcium, and cold/drought responses. Three LtpII subfamily genes, including LtpII.3, LtpII.5, and LtpII.6, were strictly expressed in flowers and seeds, and LtpIII.1 mRNA strongly accumulated in stem tissue. Subcellular localization analysis of LTP-DsRed fusion proteins revealed that the five LTPs and two LTPLs localized at the endoplasmic reticulum. The results provide new clues to further understanding the biological functions of Ltp genes.

It has been hypothesized that xylanase inhibitors play important roles in plant defense against microbial pathogens. Currently, there is little information available about xylanase inhibitor OsXIP in rice and its gene expression. We cloned a xylanase inhibitor gene OsXIP from rice (Oryza sativa L. cv. Nipponbare) genomic DNA. To determine the function of OsXIP, we generated OsXIP-overexpressing transgenic rice plants. The transgenic plants had significantly higher OsXIP expression and showed enhanced defense response to Magnaporthe oryzae compared to the wild-type plants. The results also showed that the increased OsXIP expression was accompanied by the up-regulation of pathogenesisrelated genes. To clarify the OsXIP expression pattern, a ProOsXIP::GUS vector was constructed and transgenic plants were obtained. GUS staining results revealed that OsXIP showed organ-specific expressions in rice plants. OsXIP was primarily expressed in the roots and in the veins, but it was weakly expressed in the leaves. Analyses of the OsXIP expression in response to biotic and abiotic stresses indicated that it was drastically induced by biotic stresses and methyl jasmonate treatment. OsXIP, a member of a new class of antifungal proteins, may function as a barrier that prevents the cell wall degradation by xylanases excreted by fungal pathogens. The OsXIP was found to be a stressresponsive gene and it could take part in plant defense via a JA-mediated signaling pathway.

Within the last two decades, plant viral vectors have emerged as an excellent tool for the expression of foreign peptides and proteins. Virus particles carrying foreign antigenic epitopes present some interesting advantages for vaccine design and other applications. This review covers recent advances in the use of some typical plant viruses with helical particles that present heterologous peptides with particular emphasis on particles derived from the Potato virus X (PVX) and its uses.

The root specificity and phosphate (Pi) deficiency responsiveness of high-affinity phosphate transporter (PHT1) genes point to their promoters as a sustainable system to drive Pi acquisition-related transgenes in plants. In this study, a 3-kb promoter of the AtPHT1;4 gene from Arabidopsis thaliana fused to the β-glucuronidase (GUS) reporter gene was biolistically introduced into wheat (Triticum aestivum L.) and functionally characterized in transgenic plants grown in hydroponics and in pots with soil under various Pi supply rates. From among 27 T₁ progeny derived from 250 T₀, four transgenic lines reached T₃, with two of them showing detectable GUS activity in the roots of T₄ plants. An unusually high number of transgene insertions characterized these transgenic lines, along with an irregular pattern of histochemical GUS staining and weak GUS activity. GUS expression driven by AtPHT1;4 was consistently higher under most assay conditions, as it was unaffected by 0 to 0.5 mM Pi in hydroponically grown plants, as well as by 16 to 20 mg(P) kg^-1(soil) in potted plants. Raising the soil P up to or above 40 mg kg^-1 significantly down-regulated the quantity of GUS transcripts. These results show that the responsiveness of the AtPHT1;4 promoter to Pi availability in transgenic wheat was restricted to soil-grown plants, which highlighted the relevance of the substrate and Pi supply rates in assessing molecular responses to Pi deficiency.

This work studied the six β-galactosidases (BGALs) of the subfamily a1 of Arabidopsis, that have been proposed to play important roles in the cell wall remodelling during plant development, although their precise functions are still unknown. Knockout mutants bgal1, bgal2, bgal3, bgal4, bgal5, and bgal12 of Arabidopsis and their wild type (WT) plants were analysed to determine their morphology and composition of their cell walls. The gas chromatography and the Fourier transform infrared spectroscopy revealed differences between the mutants and their WT such as in the proportions of glucose, galactose, or xylose in bgal2 and bgal4 and in cell walls polysaccharides in bgal1, bgal3, and bgal5. However, these slight changes did not result in morphological variations during plant development. None of the mutant seedlings displayed a clear reduction in β(1,4)-galactan content, analysed by immunolocalization. The absence of significant phenotypic changes in the β-galactosidase subfamily a1 mutants could indicate possible β-galactosidases functional redundancy. Future studies will focus on the construction of multiple mutants that help to establish the precise function of each member of the β-galactosidase subfamily a1.

Tricyrtis spp., which belong to the family Liliaceae, produce unique flowers, whose tepals have many reddish-purple spots. Although elucidation of a molecular mechanism of tepal spot formation and molecular breeding for flower colour alteration are desired for Tricyrtis spp., only one flavonoid biosynthesis-related gene, TrCHS encoding chalcone synthase (CHS), has been isolated so far. In the present study, comprehensive isolation and expression analysis of the other flavonoid biosynthesis-related genes were carried out in Tricyrtis sp. Six genes (TrCHI, TrF3H, TrF3'H, TrFLS, TrDFR, and TrANS) encoding biosynthetic enzymes chalcone isomerase (CHI), flavanone-3-hydroxylase (F3H); flavonoid 3'-hydroxylase (F3'H), flavonol synthase (FLS), dihydroflavonol 4-reductase (DFR), and anthocyanin synthase (ANS) as well as three genes (TrMYB1, TrbHLH2 and TrWDR) encoding transcription factors myeloblastosis 1 (MYB1), basic helix-loop-helix (bHLH), and WD40 repeats (WDRs) were newly isolated. Phylogenetic analysis showed that each isolated gene was classified into the monocotyledonous clade. Deduced amino acid sequences of DFRs showed that TrDFR has no substrate specificity. "Early" genes in the flavonoid biosynthetic pathway (TrCHS, TrCHI, and TrF3H) were constantly expressed in tepals during flower development, whereas expression of "late" genes (TrF3'H, TrFLS, TrDFR, and TrANS) varied with the flower developmental stage. Expression patterns of the late genes were mostly correlated with those of transcriptional factor genes, indicating that the late genes may be under the control of a transcription factor complex consisted of TrMYB1, TrbHLH2, and TrWDR. Accumulation of anthocyanins in tepals occurred slightly after transcriptional upregulation of the late genes. Results obtained in the present study may be valuable for further studies on flower colour and flower colour pattern in Tricyrtis spp.

Zea mays L. is less tolerant to drought than Sorghum bicolor L. In the present study, we investigated the response of both plants to drought stress applied under field conditions by withholding water for 10 d. The plant growth in terms of shoot fresh and dry masses was more severely reduced in maize than in sorghum, consistently with reduction of leaf relative water content. Gas exchange was also more inhibited by drought in maize than in sorghum. The water use efficiency (WUE) of maize fluctuated during the day and in response to the drought stress. In contrast, sorghum was able to maintain a largely constant WUE during the day in the well-watered plants as well as in the stressed ones. Studying the expression of four aquaporin genes (PIP1;5, PIP1;6, PIP2;3, and TIP1;2) revealed that PIP1;5 in leaves and PIP2;3 in roots were highly responsive to drought in sorghum but not in maize, where they might have supported a greater water transport. The expression pattern of PIP1;6 suggests its possible role in CO₂ transport in control but not droughty leaves of both the plants. TIP1;2 seemed to contribute to water transport in leaves of the control but not droughty plants. We conclude that PIP1;5 and PIP2;3 may have a prominent role in drought tolerance and maintenance of WUE in sorghum plants.

Excess radiation is one of frequent natural environmental stresses that plants have to cope with on a daily basis. Therefore, plants have evolved many short- and long-term mechanisms to acclimate to high irradiance and tolerate it. Ureides, generated from purine degradation, have been proposed as compounds involved in environmental stress responses, including altered irradiance. In the present study, high irradiance was used to investigate ureide content and gene expression in Arabidopsis thaliana. Arabidopsis plants shifted to high irradiance showed high content of a specific ureide compound, allantoin. The accumulation of allantoin was associated with increased expression of uricase, an enzyme involved in its production. When an Arabidopsis mutant (aln-3), which constitutively accumulates elevated amounts of allantoin, was exposed to high irradiance, mutant plants demonstrated enhanced tolerance to the stress conditions compared to the wild-type plants. Our results provide evidence that accumulation of the allantoin might contribute in plants response to increased growth irradiance.

During the normal developmental process, programmed gene expression is an essential phenomenon in all organisms. In eukaryotes, DNA methylation plays an important role in the regulation of gene expression. The extent of cytosine methylation polymorphism was evaluated in leaf tissues collected from the greenhouse grown plants and in in vitro-derived callus of three lowbush and one hybrid blueberry genotypes, using methylation-sensitive amplification polymorphism (MSAP) technique. Callus formation started from the leaf segments after 4 weeks of culture on a thidiazuron (TDZ) containing medium. Maximum callus formation (98 %) was observed in the hybrid blueberry at 1.0 mg dm^-3 TDZ. Although noticeable changes in cytosine methylation pattern were detected within the MSAP profiles of both leaf and callus tissues, methylation events were more polymorphic in calli than in leaf tissues. The number of methylated CCGG sites varied significantly within the genotypes ranging from 75 to 100 in leaf tissues and from 215 to 258 in callus tissues. Differences in the methylation pattern were observed not only in a tissue-specific manner but also within the genotype in a treatment specific manner. These results demonstrated the unique effect of TDZ and the tissue culture process on DNA methylation during callus development.

Dehydration responsive element binding factor (DREB) is believed to be a stress-tolerance enhancer in plants. In the present study, a cold-binding factor (CBF)/DREB homologous gene NnDREB1 (XP_010242642.1) was isolated from lotus roots using rapid amplification of cDNA ends (RACE) and reverse transcription (RT)-PCR methods. Analysis of the deduced amino acid sequence and phylogeny classified NnDREB1 into the A-1 group of the DREB1 subfamily. Expression profiling using a quantitative PCR method revealed that NnRDEB1 was significantly induced by NaCl, mannitol, and polyethylene glycol, but not by low temperature and abscisic acid. To evaluate function of NnRDEB1, Arabidopsis thaliana was transformed with the NnDREB1 gene in a binary vector construct. The transgenic plants exhibited higher resistance to drought compared with the wild-type plants in terms of survival rates, dry and fresh masses, and chlorophyll content. In addition, overexpression of NnDREB1 resulted in higher germination rates compared with the wild type plants on MS medium containing mannitol. The expressions of downstream target stressrelated genes, including cold-regulated15B (COR15B), rare cold inducible 2B (RCI2B) and repeat domain 26 (RD26), were activated in the transgenic plants. Taken together, the results suggest that NnDREB1 might be an important protein in lotus root drought tolerance.

To investigate the biochemical and physiological responses of Masson pine (Pinus massoniana Lamb.) seedlings to lead stress, needles, stems, and roots of two-year-old seedlings were treated with ²⁰⁷PbCO₃ for 33 d and then analyzed 1 and 7 d after the treatment was completed. Chlorophyll (Chl) b responded more sensitively than Chl a to needle Pb treatment, and the Chl content in the needles significantly decreased after Pb application to roots. The malondialdehyde and proline content remained almost unchanged, but superoxide dismutase and catalase activities increased on day 1 after all ways of Pb application. The reduced glutathione (GSH) content and GSH/oxidized glutathione ratio increased on day 1 after Pb application to stem or needles compared to the controls. At 7 d after the Pb application, the increase in dehydroascorbate (DHA) content and the decrease in the ascorbate (AsA)/DHA ratio implied a decreased antioxidant capacity of AsA. The results indicated that the antioxidants were sensitive to the Pb treatments and might be involved in the Masson pine tolerance to Pb stress.

The aim of this study was to find a correlation between the freezing tolerance of three chickpea (Cicer arietinum L.) cultivars (İnci, Işik-05, and Sari-98) and their wild relative C. echinospermum and physiological responses. Chickpea plants (15-d-old) were subjected to cold acclimation (CA) (10 °C for 7 d), freezing (-3 or -5 °C for 2 h), and subsequent rewarming (25 °C for 7 d). In two separate experiments with three replications, we determined growth, water status, photosystem 2 photochemical activity, photosynthetic pigments, H₂O₂, malondialdehyde, and proline content, relative leakage ratio, antioxidant enzyme activities, and gene expressions in cultivars different in freezing tolerance. Freezing temperatures adversely affected all the physiological parameters of all cultivars. Rewarming did not lead to complete recovery. The cultivar İnci was more tolerant to the freezing temperatures than others.

The cation/H⁺ exchange is a basic process in transmembrane transport. The acquisition of genome sequences has now established that plants possess genes encoding a large number of cation/proton antiporter 1 (CPA1) proteins, few of which have been characterized with respect to their contribution to ion homeostasis. The CPA1s comprise plasma membrane, vacuolar, and endosomal forms, and they have been identified as important for a salinity tolerance. They are, however, also involved in both the control of cellular pH and K⁺ homeostasis, and regulate processes over a wide range of physiological events, from vesicle trafficking to development.

We compared C₃ and CAM (crassulacean acid metabolism) states in Mesembryanthemum crystallinum, a facultative CAM species, with respect to the involvement of phosphoenolpyruvate carboxylase (PEPC) and nitrogen metabolismrelated enzymes in plant response to Botrytis cinerea infection. The enzyme activities were monitored both in pathogeninoculated 2^nd leaf pair and non-inoculated 3^rd leaf pair. The control activities of most studied enzymes were dependent on the mode of photosynthesis. Compared to C₃ plants, those performing CAM exhibited higher PEPC, nitrate reductase (NR), and deaminating glutamate dehydrogenase (NAD-GDH) activities but lower glutamine synthetase (GS) and alanine aminotransferase (ALT) activities. Regardless of the mode of photosynthetic carbon assimilation, the plants responded to infection with enhancement of PEPC and inhibition of NR activities in the inoculated leaves. Whereas the activity of GS remained unaffected, those of all glutamate-yielding enzymes, namely ferredoxin-dependent glutamate synthase (Fd-GOGAT), aspartate aminotransferase (AST), ALT, and aminating glutamate dehydrogenase (NADHGDH) were altered after infection. However, the time-course and extent of the observed changes differed in C₃ and CAM plants. In general, CAM plants responded to infection with an earlier increase in PEPC and Fd-GOGAT activities as well as later inhibition of NR activity. Contrary to C₃ plants, in those performing CAM the activities of PEPC, Fd-GOGAT, NADH-GDH, and AST in the non-inoculated 3^rd leaf pair were similarly influenced by infection as in leaves directly inoculated with the pathogen. This implies that the local infection induced an alteration of carbon/nitrogen status in healthy upper leaves. This reprogramming resulting from changes in PEPC and nitrogen metabolism-related enzymes was C₃- and CAM-specific.

Both lignin and silicon (Si) are major players in the resistance of plants to mechanical stress (MS). Focusing on the phenolic metabolism, here we studied the short-term effects of a local MS on tobacco (Nicotiana rustica L. cv. Basmas) plants with Si (+Si, 1 mM Na₂SiO₃) and without Si (‒Si) treatments in order to see how Si may modify local and systemic responses. One week after starting the Si treatment, a half of the plants were exposed to a mechanical pressure applying 980 Pa for 24 h on the upper side of the 3^rd leaf of each plant (+MS). The rest of the plants remained unstressed (‒MS). Plants were harvested 24 h and 72 h after starting the MS and the leaves directly exposed to the mechanical stress (DMS) and those indirectly exposed to the mechanical stress (IMS) from below and above the DMS leaf were analyzed for phenolic metabolism along with the corresponding leaves from‒MS plants. In the DMS leaf, the activities of polyphenol oxidase, phenylalanine ammonia lyase, and cytosolic and covalently-bound peroxidases increased by the MS, while decreased by Si. In accordance with this in the DMS leaf, the content of soluble and cell wall-bound phenolics and lignin were enhanced by the MS but decreased by Si. Interestingly, Si influenced the pattern of response to the MS depending on whether the leaves were directly treated by the MS or not. Silicon treatment augmented MS-induced lignin accumulation in the DMS leaf while rather inhibited lignin formation in the IMS leaves. These data show that Si modified MS-mediated changes in the phenolic metabolism differently in local and systemic leaves.

Reverse transcription of RNA followed by real-time quantitative PCR (qPCR) is to date the most reliable method for gene expression studies. However, to control the errors introduced along the numerous experimental procedures, it requires a normalization using internal reference genes with stable expression. To address this issue, nine candidate reference genes were investigated in Ilex paraguariensis leaves subjected to water stress. To facilitate the selection, we analysed the real-time qPCR data with three different software programs. The obtained results support the conclusion that RNA polymerase associated protein rtf1 homolog (RTF) combined with any of the following pairs is the most suitable triad of genes to compute a normalization factor: elongation factor 1-alpha + tubulin alpha chain (EF1a + α-Tub), actin + cyclophilin 38 (ACT + CYP38), or cyclophilin 38 + vacuolar protein sorting-associated protein 18 homologs (CYP38 + VPS). Our analysis constitutes the first in-depth study to identify the appropriate reference genes for the quantification of transcription in Ilex paraguariensis leaves during drought and provides essential information for further gene expression studies in this tree species.

Pseudoroegneria libanotica is an important herbage diploid species possessing the St genome. The St genome participates in the formation of nine perennial genera in Triticeae (Poaceae). The whole chloroplast (cp) genome of P. libanotica is 135 026 bp in length. The typical quadripartite structure consists of one large single copy of 80 634 bp, one small single copy of 12 766 bp and a pair of inverted regions (20 813 bp each). The cp genome contains 76 coding genes, four ribosomal RNA and 30 transfer RNA genes. Comparative sequence analysis suggested that: 1) the 737 bp deletion in the cp of P. libanotica was specific in Triticeae species and might transfer into its nuclear genome; 2) hot-spot regions, indels in intergenic regions and protein coding sequences mainly led to the length variation in Triticeae; 3) highly divergence regions combined with negative selection in rpl2, rps12, ccsA, rps8, ndhH, petD, ndhK, psbM, rps3, rps18, and ndhA were identified as effective molecular markers and could be considered in future phylogenetic studies of Triticeae species; and 4) ycf3 gene with rich cpSSRs was suitable for phylogeny analysis or could be used for DNA barcoding at low taxonomic levels. The cpSSRs distribution in the coding regions of diploid Triticeae species was shown for the first time and provided a valuable source for developing primers to study specific simple sequence repeat loci.

Cadmium (Cd) is a major abiotic stressor that affects plant growth and reduces the productivity of field crops. Here, we examined the ultrastructural, physiological, and molecular changes in three wheat cultivars [Sumai 3, Jingdong 8 (JD 8), and Nannong 9918 (9918)] in response to different concentrations of Cd (0, 10, 50, and 100 μM) in 1/4 Hoagland nutrient solution. The results showed that JD 8 contained the lowest shoot Cd content and the highest root Cd content among the three cultivars at higher Cd concentrations and so JD 8 was proposed to be a relatively Cd-tolerant cultivar. Next, the stress responses of JD 8 and 9918 were compared. Cadmium reduced root growth and size and number of the leaves, inhibited root hair development, and promoted leaf cell death. The result of trypan blue staining showed that the dead leaf cells induced by Cd stress gradually emerged in the xylem, supporting the hypothesis that cell death could restrict Cd transport. The Cd-induced deterioration of the leaf ultrastructure led to the complete disorganization of the chloroplasts, which had lower amounts of transitory starch and an increased number of osmiophilic granules compared to those in the untreated controls. Autophagy-related genes and autophagy in the leaves were induced by Cd stress. At the same concentration and Cd treatment time, the Cd-tolerant genotype JD 8 exhibited less toxic symptoms compared to the Cd-sensitive genotype 9918. The results of this study provide insights into the ultrastructural and physiological damages induced by Cd stress, which may help in selecting Cd-tolerant wheat cultivars.

Heat causes stress in blueberry; therefore, the present study aimed to investigate whether exogenous ferulic acid (FA) might protect plants against heat stress and to analyze possible mechanisms underlying such protection. Blueberry (Vaccinium corymbosum) seedlings were pretreated with 0.6 mM FA for 1 d and then kept at normal (25/20 °C) or elevated (39/30 °C) temperatures for 3 d. One day of FA pretreatment increased transcriptions of genes encoding iron superoxide dismutase, cytoplasmic copper/zinc superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase and elevated content of proline and soluble sugars in leaves. When the FA-pretreated blueberries were exposed to heat, transcriptions of these genes and content of proline and soluble sugars were higher than after heat treatment alone. Under heat, FA pretreatment also enhanced transcriptions of genes encoding chloroplast copper/zinc superoxide dismutase, catalase, glutathione peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase. This corresponds with increased activities of superoxide dismutase and glutathione peroxidase and is consistent with elevated content of ascorbate and glutathione in the FA-pretreated and heat-stressed blueberries. Compared with heat treatment alone, the combination of FA pretreatment and heat enhanced content of endogenous FA, decreased production of superoxide anion, and content of hydrogen peroxide and malondialdehyde, and also increased relative water content and osmotic potential in the leaves. Thus, pretreatment with FA mitigated the heat stress in the blueberries by elevating endogenous FA content, reducing accumulation of reactive oxygen species, and increasing proline and soluble sugar content.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) serves not only as a key enzyme in glycolysis, but also as a multifunctional protein in other biological processes, especially in response to abiotic stresses in plants. Cytosolic GAPDH (GAPC) is a typical redox protein with selected catalytic cysteine, which undergoes reversible redox post-translational modifications (RPTMs) on its thiol group by reacting with hydrogen peroxide and nitric oxide related species. Moreover, the modified GAPC may interact with certain signal transmitters such as phosphatidic acid, phospholipase D, and osmotic stress-activated protein kinase. All these observations suggest that GAPC serve as a key mediator in redox signal transduction in plants. In this review, we provide an up-to-date insight into molecular mechanisms after H₂O₂- and NO-dependent oxidation of GAPC. We also discuss GAPC catalytic functions and potential functions as a modified protein by RPTMs.

Several different concentrations of α-tocopherol were applied to Carex leucochlora after plants had been treated with high salinity (0.8 % NaCl) in a greenhouse for one month. The results revealed that 0.8 mM α-tocopherol treatment showed the greatest alleviation of growth inhibition and cell membrane damage induced by salt stress. In comparison with NaCl alone, the 0.8 mM α-tocopherol application significantly decreased the content of hydrogen peroxide and the rate of superoxide radical generation, and increased the content of chlorophyll b, carotenoids, free proline, and soluble protein, but had no effect on the content of chlorophyll a and soluble sugar. These results suggest that α-tocopherol could effectively protect C. leucochlora plants from salt stress damage presumably by quenching the excessive reactive oxygen species to protect the photosynthetic pigments and by enhancing the osmotic adjustment.

WRKY transcription factors (TF) family is involved in a huge variety of plant processes, including seed germination, plant development, phytohormone signalling, and defence against both biotic or abiotic stresses. In this work, WRKY TF family has been characterized in citrus. In a first experiment, the relative expression of CsWRKYs was analyzed in shoots and roots of plants treated with abscisic acid (ABA), salicylic acid (SA), and methyl jasmonate (MeJA) under in vitro conditions. Expression of CsWRKYs was also determined in roots of commercial citrus rootstocks subjected to osmotic and salt stresses. A total amount of 50 CsWRKYs has been found and devided into different groups of WRKY family according to the WRKY domain sequences. In response to the applications of phytohormones, the highest differences were observed in roots, and it was found that ABA and SA generally repressed CsWRKYs expressions, but MeJA induced their overexpression. Osmotic stress repressed the expression of most of the CsWRKYs, whereas salt stress induced their expression. Moreover, salt stress induced higher increase in CsWRKY expressions in the tolerant rootstock Citrus macrophylla than in the sensitive rootstock Carrizo citrange, suggesting that these TFs may play an important role in response to this stress.

This study investigated the role of hydrogen sulfide (H₂S) in the regulation of the ascorbate (AsA) and glutathione (GSH) metabolism by jasmonic acid (JA) in the leaves of Arabidopsis thaliana by using H₂S scavenger hypotaurine (HT) and H₂S synthetic mutant (SALK_041918, designated Atl-cdes). The results showed that JA significantly increased the H₂S content, the activities of L-cysteine desulfhydrase (L-CDes), D-cysteine desulfhydrase (D-CDes), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), L-galactono-1,4-lactone dehydrogenase (GalLDH) and γ-glutamylcysteine synthetase (γ-ECS), the ratio of AsA to dehydroascorbate (DHA), and decreased the content of malondialdehyde (MDA) and H₂O₂ in the wild type of A. thaliana, compared to control. The above effects of JA except the increased activities of L-CDes and D-CDes were suppressed by addition of HT. However, JA and HT+JA had no significant effects on the ratio of reduced GSH to oxidized GSH (GSSG) in the wild type of A. thaliana. Application of HT to the control decreased H₂S content, AsA/DHA ratio, and activities of APX, GR, DHAR, MDHAR, γ-ECS, and GalLDH, but had no effects on MDA content, activities of L-CDes and D-CDes, and GSH/GSSG ratio. In the H₂S synthetic mutant, JA had no obvious effects on above mentioned parameters except the D-CDes activity compared with the control. Our results suggest that JA-induced H₂S, which is a signal that leads to the up-regulation of the AsA and GSH metabolism.

Transcription factors are involved in lipid metabolism, and in present study, the transcription factor WRINKLED 1 (GhWRI1) was cloned from Gossypium hirsutum L. cv. Coker 201 by reverse transcription (RT)-PCR and rapid amplification of cDNA ends. The Pro35S:WRI1 vector was constructed and transformed into upland cotton cv. Sumian 20 using the pollen tube pathway method. After PCR and Southern blot verification of the positive transgenic plants, T₂ transgenic lines derived from T₁ individuals with the insertion gene in a single copy were chosen for further dissection. Semi-quantitative and quantitative RT-PCR analyses indicated that GhWRI1 gene expression increased in transgenic plants compared with that in the wild-type. Seed lipid content increased at most transgenic plants, and at the same time, protein content decreased. Compared to the control, major agronomical traits were not affected by overexpression of GhWRI1 in transgenic plants.

The NAC (NAM, ATAF1/2, and CUC2) transcription factor family participates in responses to various kinds of environmental stimuli in plants. However, the roles of NAC protein in cold resistance, especially in the cold resistance of tomatoes, are not completely understood. This study examined the roles of a tomato (Solanum lycopersicum) NAC transcription factor (SlNAC35) in resisting chilling using transgenic tomatoes. GUS staining and expression analysis revealed that SlNAC35 expression was induced at 4 °C, thereby suggesting its involvement in plant responses to chilling stress. Moreover, transgenic lines over-expressing SlNAC35 exhibited high chlorophyll content, fresh mass, and low accumulation of reactive oxygen species and membrane damage under chilling stress. These results indicated that SlNAC35 overexpression enhanced the chilling tolerance of transgenic tomatoes. High expressions of cold tolerance markers SlCOR518 and SlCOR413IM1 were observed under chilling stress in transgenic lines. This observation suggested that SlNAC35 overexpression enhanced the chilling tolerance of transgenic lines by involving the c-repeat binding factor-cold stress response (CBF-COR) signaling pathway and by regulating SlCOR expression.

Rapid and non-destructive assessment of water status is essential to enhance crop performance. This study aimed to evaluate photosynthetic performance and to monitor water status in cotton under field conditions. A two-year experiment was conducted with three irrigation regimes to measure the following parameters: photochemical reflectance index (PRI), structural independent pigment index (SIPI), water index (WI), solar-induced fluorescence (SIF; retrieved from reflectance by using Fraunhofer line-depth method), gas exchange, and chlorophyll fluorescence (CF). The results showed that PRI decreased > 30 % in moderate drought (MD) and >50 % in severe drought (SD), compared with control. PRI was found to be positively correlated with net photosynthetic rate (P_N), stomatal conductance (g_s), transpiration rate (T_r), actual quantum yield of photosystem II photochemistry (Φ_PSII), but a negatively correlated with nonphotochemical quenching (NPQ). Solar-induced fluorescence around 761 nm (SIF₇₆₁) had significant correlations with P_N, Φ_PSII, and NPQ, but not with maximal quantum yield of PS II photochemistry (F_v/F_m). The relationship between PRI and PN was stronger at the beginning of water stress (R² = 0.86) than for the all stress stages (R² = 0.54), indicating that PRI could be more effective for assessing PN of cotton at early water stress. PRI was better correlated with relative water content and photosynthetic parameters than SIPI and WI and so it could also be a good indicator to evaluate cotton water status.

Cold stress is one of the major limitations to crop productivity worldwide. We investigated the effects of multiple gene expression from cold tolerant Capsella bursa-pastoris in transgenic tobacco (Nicotiana tabaccum) plants. We combined CblCE53 and CbCBF into a reconstruct vector by isocaudomers. Plant overexpression of CbICE53 under the stress inducible CbCOR15b promoter and CbCBF under a constitutive promoter showed increased tolerance to both chilling and freezing temperatures in comparison to wild-type plants, according to the electrolyte leakage and relative water content. The expressions of endogenous cold-responsive genes in transgenic tobacco (NtDREB1, NtDREB3, NtERD10a and NtERD10b) were obviously upregulated under normal and low temperature conditions. These results suggest that the CbICE53 + CbCBF transgenic plants showed a much greater cold tolerance as well as no dwarfism and delayed flowering. Thus they can be considered as a potential candidate for transgenic engineering for cold tolerant tobacco.

Leymus chinensis (Trin.) Tzvel is a rhizomatous grass species in the Eastern Eurasian steppe zone that is often limited by low soil nitrogen availability. Although a previous study showed that the rhizomes of L. chinensis have the capacity to take up nitrogen, the importance of such uptake for nitrogen nutrition is unclear. Moreover, little is known regarding the inorganic nitrogen uptake kinetics of roots and rhizomes in response to nitrogen status. Here, we first found that ammonium is preferred over nitrate and glycine for L. chinensis growth. Using the ¹⁵N-labelling method, we found that the rate of ion influx into roots was approximately five-fold higher than into rhizomes under the same nitrogen content, and the ion influxes into roots and rhizomes under 0.05 mM N were greater than in the presence of 3 mM N, especially in the form of NH₄⁺. Using a non-invasive micro-test technique, we characterised the patterns of NH₄⁺ and NO₃^- fluxes in the root mature zone, root tip, rhizome mature zone, and rhizome tip following incubation in the solution with different N compounds and different N concentrations. These results suggest a dynamic balance between the uptake, utilisation, and excretion of nitrogen in L. chinensis.