Irradiance is one of the main limiting factors affecting the production of pepper (Capsicum annuum L.) in facility production. It is therefore important to measure the growth of pepper seedlings under low irradiance and to understand how to relieve low radiation stress. In this study, pepper seedlings were cultivated under low irradiance and were treated with gibberellic acid (GA₃) and paclobutrazol (PP333). Agronomic and physiological characteristics of the pepper seedlings were analyzed. Under low irradiance, the plant height, leaf area, and the chlorophyll (Chl) and malondialdehyde (MDA) content of pepper seedlings were higher than under normal irradiance, while the content of proline, and soluble protein and Chl a/b ratio of pepper seedlings were lower than those under normal irradiance; exogenous GA₃ had a similar effect. When PP333 was applied to the seedlings, abnormal growth was mitigated. The effects of exogenous GA₃ and PP333 on Chl fluorescence parameters were also analyzed. Under low irradiance, the maximum quantum yield reduction of photosystem (PS II) (F_v/F_m) increased significantly, and the reaction center initiated the corresponding defense mechanism for timely dissipation of excess excitation energy to reduce the damage to the plant. These results showed that spraying gibberellin under normal irradiance conditions had similar effects on pepper seedlings as under low irradiance conditions. Exogenous PP333 relieved the growth reduction by increasing the content of Chl and soluble protein and enhancing some photosynthetic parameters. These results suggest that exogenous PP333 can alleviate the abnormal growth of pepper under low radiation stress.

The impact of persisting herbicide residues on succeeding crops is of great concern to farmers because even the presence of very low concentrations can inhibit growth of crop and cause crop reduction. Furthermore, wastewater irrigation can lead to cadmium accumulation in soils. Thus, the co-occurrence of low amounts of herbicide residues and cadmium within agricultural fields are difficult to avoid. How the combination of these two pollutants affect plant metabolites remains to be elucidated and thus warrants investigation. Maize seeds were planted in soil that had been sprayed with chlorsulfuron and Cd, then we studied the effects of exposure to the herbicide chlorsulfuron (0.001, 0.003, 0.005, 0.008, and 0.010 mg kg^-1) and cadmium (as 5.0 mg kg^-1 CdCl₂) on maize seedlings by utilizing nuclear magnetic resonance (NMR) after 21 d. Principle component analysis of ¹H NMR spectra clearly discriminated between control and treatment groups. Compared with chlorsulfuron-only treatments, treatments using both contaminants showed higher content of phenolic acids, aspartic acid, choline, β-galactose, and α-glucose in the seedlings. Contrary to previous reports, we found larger pools of branched-chain amino acids in seedlings exposed to chlorsulfuron and CdCl₂. These findings indicate that CdCl₂ did not aggravate the effects of chlorsulfuron on maize seedlings metabolites. CdCl₂ elicited significant changes in plant metabolism at a concentration that did not impair plant growth. Moreover, chlorsulfuron did not inhibit branched chain amino acid synthesis.

Abiotic stresses strongly impair plant development and might impose detrimental effects particularly on seedlings. Irradiance and water deficit are relevant factors, which affect performance of young plants under controlled conditions. In our study, we investigated the influence of water shortage combined with different radiation sources - light emitting diodes (LED) and compact fluorescence lamps (CFL) - on physiological and biochemical parameters of young apple plants. Stress responses were assessed by fluorescence-based indices, while relative water, chlorophyll (Chl), and proline content served as reference parameters. The watering regime had a higher impact on biochemical indicators than the radiation sources. Lower Chl content was determined in plants grown under LED both in control and in water deficit plants. Nitrogen balance index and nitrogen balance index with red radiation excitation showed similar patterns regarding leaf Chl results in relation to the radiation source, being higher under CFL. In contrast, the flavonol index was higher in plants cultivated under LED. Stomatal conductance and maximal photochemical efficiency emphasised a radiation quality effect with higher values for CFL. In conclusion, fluorescence indices related to nitrogen status and flavonol content are promising parameters to sense physiological impairments under the given conditions. However, discrepancies compared to previous studies might be related to the different plant species, the nature of dehydration, and the measuring conditions.

Phylogenetic analysis has become a common step in characterization of gene and protein sequences. However, despite the availability of numerous affordable and more-or-less intuitive software tools, construction of biologically relevant, informative phylogenetic trees remains a process involving several critical steps that are inherently non-algorithmic, i.e., dependent on decisions made by the user. These steps involve, but are not limited to, setting the aims of the phylogenetic study, choosing sequences to be analyzed, and selecting methods employed in sequence alignment construction, as well as algorithms and parameters used to construct the actual phylogenetic tree. This review aims towards providing guidance for these decisions, as well as illustrating common pitfalls and problems occurring during phylogenetic analysis of plant gene sequences.

Vacuole membrane proteins play a critical role in the regulation of plant physiological processes including normal growth and development, and responses to stresses. The killing me slowly 1 (KMS1) gene that encodes a soluble N-ethylmaleimide-sensitive fusion attachment receptor (SNARE) domain-containing vacuole membrane protein was first reported in Arabidopsis. Currently, the function of KMS1 in other plants under stress is poorly understood. In this study, we report cloning, expression, and characterization of a novel KMS1 gene in alfalfa (Medicago sativa L.), designated MsKMS1 (GenBank accession No. JX467688). The full-length cDNA of MsKMS1 was 1 396 bp and contained a complete open reading frame of 1 257 bp, which encoded a putative protein of 418 amino acids. The BLASTp analysis showed that MsKMS1 shared high amino acid sequence similarities with KMS1 from other plants such as Medicago truncatula (99 %), Cicer arietinum (89 %), Glycine max (77 %), Prunus mume (76 %), Ricinus communis (72 %), Populus euphratica (72 %), Theobroma cacao (72 %), and Arabidopsis thaliana (67 %). Transient transformation of onion (Allium cepa) bulb scale epidermal cells by biolistic bombardment showed that MsKMS1 was localized to the plasma membrane. Quantitative real-time PCR revealed that MsKMS1 expression was upregulated under different abiotic stresses (200 mM NaCl, 20 % (m/v) polyethylene glycol 6000] and 10 mg dm^-3 abscisic acid. Transgenic tobacco plants were obtained via Agrobacterium-mediated transformation and treated with 200 mM NaCl. Reverse-transcription PCR data showed that MsKMS1 was successfully transcribed and expressed in the leaves of transgenic plants. The MsKMS1-overexpressors showed a lower malondialdehyde content and maintained a higher relative water content and proline content compared with non-transgenic controls under salt stress. These results indicate that the introduction of the MsKMS1 gene could improve salt stress resistance in tobacco plants. This study reveals the role of MsKMS1 in the regulation of plant responses to abiotic stress and provides evidence for further functional studies of the KMS1 family in alfalfa.

Salinity has a huge negative impact on plant growth and development by increasing sodium ions accumulation and potassium ions loss that deeply disturbs the plant cell homeostasis and can lead to plant cell death. The imbalance between Na⁺ and K⁺ could be solved by applying potassium silicate (K₂SiO₃). The glycine betaine (GB) is well-known to play a crucial role against oxidative stress in plants by improving the antioxidant machinery. Thus, this research aimed to apply K₂SiO₃ (1 mM) and GB (10 mM) alone or in combination against 200 mM NaCl-induced damages in Dalbergia odorifera. The results showed a significant amelioration of negative effects of salt stress on the phenotypic traits, chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency by applied substances. The contents of saccharides and proline were down-regulated by K₂SiO₃, GB, and K₂SiO₃-GB, whereas the proteins content was increased by these treatments. The contents of lipid peroxidation, superoxide anion, hydrogen peroxide were reduced by exogenous substances under stress. The activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) and the accumulation of antioxidants (glutathione and ascorbate) were enhanced by exogenous substances. The K₂SiO₃-GB combination mostly showed better effects on antioxidant machinery compared to a single treatment.

Fusarium head blight (FHB) represents a damaging disease of cereal spikes caused by mycotoxin-producing Fusarium fungi revealing adverse effects on grain quality and yield. Chinese spring wheat (Triticum aestivum L.) cv. Sumai 3 represents a major source of FHB resistance thanks to Fhb1 QTL on 3BS chromosome conferring resistance to FHB and encoding a lectin-like protein. The aim of our study lied in a comparison of proteome response to Fusarium culmorum inoculation and mycotoxin deoxynivalenol (DON) application at 10 d after inoculation (dai) in spikes of resistant wheat cultivar Sumai 3 and susceptible wheat cultivar SW Kadrilj. Proteome analysis revealed profound impact of Fusarium inoculation and mycotoxin application on plant energy metabolism. Fusarium inoculation decreased photosynthesis and ATP biosynthesis and increased the level of stress-protective proteins (chaperones such as Hsc70, lectins). Genotype related differences observed at 10 dai indicated an active acclimation in Sumai 3 as indicated by increased content of some enzymes involved in phenolics biosynthesis (phenylalanine ammonia lyase PAL, BAHD acyltransferase), jasmonate biosynthesis (lipoxygenase LOX), and oligosaccharide biosynthesis (sucrose synthase SuSy, UDP-glucose uridylyltransferase) which are an important part of glycoproteins such as lectins and other pathogen-responsive biomolecules. The study thus provides data on plant acclimation to Fusarium infection which may underlie superior resistance of Sumai 3 cultivar.

This study was carried out on Kober 5BB (Vitis Berlandieri × V. riparia) grape rootstock shoot tips during the preparatory steps preceding the direct immersion in liquid nitrogen, in order to overcome until now unsuccessful cryopreservation with this species. The exposure of shoot tips to 0.3-0.4 M sucrose leads to a high cell solute concentration. The treatment with plant vitrification solution (PVS2) alone, i.e., not followed by storage in liquid nitrogen, markedly affected shoot tip survival. After a 30 min exposure, regrowth percentage of shoot tips decreased from 94 % (control) to 57 %, and dropped to 15 % when the treatment was prolonged up to 60 min. After a 90 min exposure, no regrowth occurred. In addition, plantlets regenerated from shoot tips which underwent 60 min or more exposure to PVS2 showed signs of malformation. Microscope observations of shoot tips treated with 0.3 or 0.4 M sucrose and 30 min PVS2 showed the presence of cells starting to plasmolyze, localized in the area surrounding the apical meristem. A limited presence of starch grains in meristem and bract cells was also noted. However, the most conspicuous consequence of prolonged PVS2 treatment was convex plasmolysis. The phenomenon was dependent on the time of PVS2 exposure. Indeed, after a 30 min treatment, plasmolysis was minimal or absent, but it increased with longer exposure to PVS2 at 4 °C.

Tomato yellow leaf curl virus (TYLCV), a whitefly-transmitted single-stranded DNA (ssDNA) virus, causes the most important viral disease of tomato worldwide. TYLCV-mediated disease is mainly controlled via extensive insecticide sprays aiming at the whitefly vector. RNA-based vaccination was proven to be a non-transgenic approach leading to efficient plant virus control. In this work, double-stranded RNA (dsRNA) molecules deriving from sequences of the C4 and V2 genes of TYLCV-Mild were produced in vitro and topically applied onto tomato plants along with the virus (via agroinfiltration). DsC4 and dsV2 application reduced disease incidence to 23 and 46 %, respectively, while TYLCV positive control reached 64 %. Bioinformatics analysis of the virus-specific small interfering RNAs (vsiRNAs) from TYLCV-infected tomato revealed 'hot' and 'cold' spots in the TYLCV-Mild genome. Interestingly, the viral C-strand had twofold siRNA reads when compared to that of the V-strand. Overall, vsiRNAs of negative and positive polarity were almost equal (53.5 vs. 46.6 %); vsiRNAs of negative polarity prevailed at the V-strand. Stem-loop RT-PCR validated the presence of six vsiRNAs (hot or cold spots) in TYLCV-Mild-infected and dsRNA-treated tomato. The exogenously applied dsRNA was found to rapidly move systemically in tomato and was detected for 54 days post treatment (dpt). The applied dsRNA molecules were successfully processed by the Dicer-like proteins (DCLs) in tomato since small interfering RNAs (siRNAs) deriving from the dsRNA were detected for at least 54 dpt. This consists the first report of dsRNA-based vaccination applied against a monopartite geminivirus.

The myeloblastosis (MYB) transcription factors are essential for plant stress responses. They can enhance plant tolerance to abiotic stresses (e.g., drought, salinity, and cold) via improved physiological and biochemical responses including the accumulation of metabolites. In this study, we constructed a Panax ginseng MYB4 (PgMYB4) gene expression vector and established the stable transgenic Arabidopsis thaliana lines to study the effects of this gene on plant stress tolerance. The germination rate and seedling taproot length were greater for the PgMYB4-overexpressing plants than for the wild-type plants. Accordingly, the overexpression of PgMYB4 in Arabidopsis enhanced seedling tolerance to drought, salt, and cold conditions. Under drought stress, the relative chlorophyll content decreased less, the proline content increased more, and the water loss rate decreased more in the transgenic plants than in the wild type. The expressions of stress-related genes responsive to dehydration 19A, responsive to dehydration 22, responsive to desiccation 29A, cold-regulated 15A, cold-regulated 47, and pyrroline-5-carboxylate synthase 1 were significantly upregulated in the transgenic Arabidopsis plants. Under high salt stress, the kinesin 1 (KIN1) expression was significantly upregulated in the transgenic plants. In response to the low temperature stress, the dehydration-responsive element binding protein 2A and KIN1 expressions increased dramatically in the transgenic Arabidopsis plants. Thus, PgMYB4 positively regulated the stress tolerance gene networks, which promoted the expression of anti-stress effector genes. This gene may be useful for ginseng breeding programs aiming to develop new cultivars with enhanced stress tolerance.

Chlorophyllases (Chlases) are housekeeping proteins in plant cells. The dephytylating enzymes can catalyze chlorophyll (Chl) to form chlorophyllide, but the distribution of Chlases in plant cells is still an interesting debate. Previously, we showed that PmCLH2 was a nuclear-encoded gene, and PmCLH2 protein was located in cytosol and chloroplasts of Pachira macrocarpa (Pm). In this study, the antibody of PmCLH2 was made and used by the immunogold-labelling technique to detect the localization of Chlase of Pm leaves at four developmental stages (young, mature, yellowing, and senescent). The transmission electron microscopy results show that Chlases were comprehensively found in parts of the chloroplast, such as the inner membrane of the envelope, grana, and the thylakoid membrane as well as in cytosol, and vacuoles at young, mature, and yellowing stages of Pm leaves, but not in the cell wall, plasma membrane, mitochondria, and nucleus. In short, PmCLH2 was mainly detected in vacuoles at the senescent stage, but a few were found in the chloroplasts. A pathway is proposed to explain the birth and death of Chl, Chlase, and chloroplasts in higher plants.

Stilbene synthases (STS) are plant enzymes that are responsible for the biosynthesis of stilbenes, which are plant phenolic compounds with valuable biological properties. Stilbenes also play important roles in plant tolerance to biotic and abiotic stresses. Therefore, plants that overexpress STS genes can be more resistant to various stresses. This paper investigated the effects of STS gene overexpression in Arabidopsis thaliana (L.) Heynh. Columbia-0 plants on stilbene content and tolerance to the following abiotic stresses: low and high temperatures, salinity, drought, and ultraviolet irradiation (UV-B and UV-C). We used VaSTS1 and VaSTS7 genes from grapevine (Vitis amurensis Rupr.) expressed under the double cauliflower mosaic virus 35S (CaMV35S) promoter. This study firstly demonstrated that overexpression of the VaSTS1 and VaSTS7 genes in A. thaliana plants considerably increased plant tolerance to UV-B and UV-C, while the tolerance to the low and high temperatures, salinity, and drought was not affected. We showed that the highest trans-piceid and trans-resveratrol total content was in ST1 A. thaliana plants that overexpressed the VaSTS1 gene in the range 8.28 - 22.66 µg g^-1(f.m.). ST7 plants that overexpressed the VaSTS7 gene showed only trans-resveratrol at 0.02 - 0.08 µg g^-1(f.m). Stilbene content and UV tolerance in transgenic A. thaliana plants correlated with STS transgene expression. STS expression, UV tolerance, and stilbene content was higher in VaSTS1 transgenic plants compared with that in VaSTS7 transgenic plants.

Thioredoxins are oxidoreductases that help to maintain redox homeostasis in plants under abiotic stress. In this study, a new thioredoxin gene, SikTrxh, was cloned from Saussurea involucrata (Kar. & Kir.), a perennial herb that grows in the high alpine mountains of Central Asia. Bioinformatics analysis shows that the full-length cDNA of SikTrxh consisted of 565 bp with a 354-bp open reading frame and encoded a 117 amino acid protein. Using quantitative reverse transcription (RT) PCR, we found that the expression of the SikTrxh gene was induced by salt, cold, and drought stresses, suggesting that this protein played a significant role in plant defense. Subcellular localization confirmed that the protein was localized to the mitochondria. A vector carrying SikTrxh was inserted into tobacco, and successfully modified plants were identified by RT-PCR. Physiological indicators and antioxidant enzyme activities were measured under low temperature, and salt and drought stresses. Our results show that malondialdehyde content and relative electrolyte leakage increased in both wild-type and SikTrxh-overexpressing transgenic plants; however, these increases were significantly higher in the wild-type plants than in the transgenic plants. We also found that photosystem II photoinhibition was lower in the transgenic plants than in the wild-type plants, and that activities of reactive oxygen species-scavenging enzymes were higher in the transgenic plants than in the wild-type plants. We conclude that SikTrxh can reduce toxic effects of reactive oxygen species to protect the plasma membrane, thereby increasing plant resistance to abiotic stresses.

In Arabidopsis, there are 14 TFIIB-like proteins that have been phylogenetically categorized into the TFIIB, BRF, and Rrn7/TAF1B/MEE12 subfamilies. The TFIIB transcription factor (TF) subfamily plays a key role in the regulation of gene expression in eukaryotes. To identify the expression patterns of some members of the TFIIB and BRF subfamilies in A. thaliana, different approaches were carried out to determine the possible functions of some of these transcription factors. Through an in silico analysis, we identified possible cis-acting regulatory elements in the promoter regions that drive the expression of transcription factors, as well as we evaluated their expression by means of real-time qPCR, at different growth stages and under various stress conditions. Cis-acting elements analysis showed that general transcription factors possess stress-responsive elements such as W-Box (TTGACC/T type binding WRKY TFs), ARF1 (auxin response), MYB binding site promoter (auxin response and elicitors), RAV1-A (response to dehydration and salinity), and DRE elements (dehydration response) among others. The experimental results showed differential expression of TFIIB1 and TFIIB. In addition, we demonstrate that in stress conditions a transcript of the TFIIB1 factor is generated as an alternative splicing product by retention of the third intron, where a premature termination codon is found. This is the first report of an alternative splicing event in a general transcription factor related to RNA pol II, which is synthesized when the plant is under abiotic stresses such as heat, dehydration, and salinity.

MRCTLH (muskelin/RanBPM/CTLH) is a protein complex found in humans (MRCTLH) that is involved in the regulation of numerous cellular processes, such as gluconeogenesis, cell signaling, development, nuclear extrusion, cell morphology, or stability of different proteins. According to genomic data, all eukaryotes have similar protein complexes. In yeast, a similar protein complex named GID was found to be involved in the regulation of gluconeogenesis. LICC1 is a maize protein whose sequence resembles that of TWA1 in humans and GID8 in yeast, which are central components of the MRCTLH and GID complexes. LICC1 contains three highly conserved protein domains, LisH, CTLH, and CRA, typical of this protein family. Twa1 and gid8 are unique genes in human and yeast genomes. However, three copies of licc1 are present in the maize genome and multiple copies are present in other plant genomes. This result suggests the presence of multiple variants of the MRCTLH/GID complex in plants, which could increase its regulatory capacity. We also demonstrate here that LICC1 has the ability to interact with microtubules, similarly to the human TWA1. This interaction reinforces the idea that the LICC1 protein from maize, and its homologues in plants and, in general, the GID/MRCTLH complex in plants, can perform biological functions similar to those in humans and yeast.

Saccharides are a direct energy source for most organisms and the primary components in grains of common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD). However, genes involved in the metabolism of primary saccharides such as glucose and fructose have not been fully characterized in wheat, which limits our understanding of how these genes influence wheat growth. In this study, genes coding ATP-dependent phosphofructokinase (PFK), fructose-1,6-bisphosphatase (FBP), and pyrophosphate-dependent fructose-6-phosphate 1-phosphotransferase (PFP), which participate in the conversion between fructose 6-phosphate (F-6-P) and fructose 1,6-bisphosphate (F-1,6-P₂), were identified at the genome-wide level. A total of 24, 13, and 12 genes were found encoding TaPFK, TaFBP, and TaPFP, respectively. All predicted peptides of these genes exhibited conserved substrate-binding domain, suggesting they are active enzymes in vivo. Transcriptome data ranked the gene levels as follows: TacyFBP-1 > TacpFBP-1 > TaPFPα-2 ≈ TaPFPβ >> TaPFK-1 ≈ TaPFK-5 >> all remaining genes at different developmental stages of wheat. In the three tapfp-a, b, and d knockout lines, there was a decrease in the plant height, anther length, and thousand-grain mass, while the percentage of abnormal pollen increased compared to that of wild type cv. Huapei3 (HP3). During germination, tapfpβ-a exhibited a lower germination rate, shorter coleoptile and primary root length, and higher fructose content than HP3, tapfpβ-b, and tapfpβ-d lines. Expressions were ranked as follows: TaPFK-5 ≈ TaPFPα-2 >> TaPFPα-1 ≈ TaPFPβ > TacyFBP-1 ≈ TaPFK-7, 9 in HP3. All these genes were downregulated during the 24 - 96 h germinating process in three mutant lines. Collectively, main TaPFK, TaFBP, and TaPFP members cooperated during wheat growth, while TaPFPβ knockout decreased wheat vitality. Results from this study can aid more systematic studies of the physiological and molecular functions of TaPFK, TaFBP, and TaPFP.

Physiological changes associated with senescence of flowers and abscission of floral parts in Oncidesa (formerly Oncidium) cv. Gower Ramsey are caused by a plant hormone ethylene which is produced by pollinia cap dislodgment during postharvest handling and transportation. The ethylene receptor gene OgERS1 of Oncidesa has been previously cloned and characterized. To analyze promoter activity of OgERS1, transgenic Arabidopsis thaliana plants were generated to express the ß-glucuronidase (GUS) reporter gene under the control of 5'-upstream sequence of OgERS1 from Oncidesa. The expression pattern of the OgERS1 promoter at the cellular level was investigated by analysis of GUS activity. This promoter can activate gene expression in both actively dividing young tissues and abscission-related aging tissues. Expression of GUS was detected in the shoot meristem uniquely in 10 to 30 d-old-plants and was found in flower buds, axillary buds, flower stems, and abscission layers during later development. In 2- to 3-week-old transgenic Arabidopsis, exogenous ethylene, glucose, lactose, and maltose enhanced promoter activity implying that crosstalk between sugar and an ethylene receptor may exist. However, indole-3-acetic acid, benzylaminopurine, abscisic acid, heat, wounding, salinity, drought, and flooding slightly suppressed promoter activity. These results demonstrate that the promoter of OgERS1 was developmentally and environmentally regulated, and imply a potential for application of this bi-functional promoter to increase branching or enhanced dwarfing.

Very little is known about lipid transfer proteins from flax (Linum usitatissimum L.). In the present work, three genes encoding a lipid transfer protein (LTP) were isolated from flax, two of which encoded Type-1 and one Type-2 LTPs with molecular masses of about 9 and 7 kDa, respectively. The analysis of deduced amino acid sequence reveals that only Type 2 of the L. usitatissimum leaf specific LTP (LuLTP_Ls) had an N terminal signal peptide consisting of 23 amino acids. The phylogenetic analyses of LuLTP_Ls suggest their closest relatedness with respective proteins from Dimocarpus longan and Vitis vinifera. The gene expression analysis shows that LTP Type 1 genes, which include LuLTP_Ls1 and LuLTP_Ls3, were progressively expressed during leaf development, whereas LuLTP_Ls4 (Type 2) was expressed only at initial and terminal senescence stages of cotyledons. The results suggest that both types of LuLTP_Ls were differentially yet significantly expressed in cotyledons implicating their function in transport and scavenging lipidic skeletons for the benefit of other developing parts of the plant.

In this study, the anthocyanin content and real-time quantitative expression of the anthocyanin biosynthesis-related genes were investigated in leaves, stems, and tubers of purple yam (Dioscorea alata L.). The anthocyanin content, its accumulation, and the expression of genes encoding phenylalanine ammonia lyase (PAL), flavanone-3-hydroxylase (F3H), anthocyanidin synthase (ANS), and UDP-glycose flavonoid glycosyl transferase (UFGT) were studied. The anthocyanin content in the leaves and stems was high at early stages of growth, but it decreased and remained at a similar level from the 35^th day onward. The anthocyanin content in the tubers firstly increased, reached a high peak at the 110^th day of growth, after which decreased. Anthocyanin accumulation rates and the expressions of the anthocyanin biosynthesis genes were high at the early stages of growth in the leaves and stems, but in tubers, two peaks were observed: at days 80 and 140 for the gene expression and at days 125 and 170 for the anthocyanin accumulation rate. Thus, there was coordination between the gene expressions and the anthocyanin accumulation rates in the various organs as well as in the entire plants.

Our research intended to appraise the performance of two different Pseudomonas strains on Zea mays L. (cv. B73) under drought stress and non-stress conditions. Plants were inoculated with P. putida KT2440 (Pp) and P. fluorescens (Pf1) followed by sampling at 0, 3^rd, and 6^th day after imposition of drought stress (DAS). Both strains demonstrated significant improvement in root length, protein content, chlorophyll content, and root and shoot fresh masses as compared to un-inoculated drought stressed plants. Real-time quantitative PCR analysis revealed that drought stress responsive genes, i.e., the cold-related dehydrin 410 gene, WRKY18, and major facilitator superfamily were significantly down-regulated by Pf1 and Pp inoculation under drought stress condition on 6 DAS. Similarly, the down-regulated transcript abundance of lipoxygenase genes in inoculated plants on 6 DAS showed the role of Pf1 and Pp in scavenging reactive oxygen species under drought stress conditions. Among the selected jasmonic acid pathway responsive genes, maize protease inhibitor and 12-oxo-phytodienoatereductase 7 (OPR7) also revealed a potential role of these rhizobacteria under drought stress conditions. Seed inoculation of both strains significantly down-regulated the expression of OPR7 gene under stress conditions. Our results advocate the complex growth promotion effects of both selected rhizobacterial strains and amelioration of the drought by modulating the expression of drought stress responsive genes.

A wide range of microorganisms found in the rhizhosphere are able to regulate plant growth and development, but little is known about the mechanism by which epiphytic microbes inhibit plant growth. Here, an epiphytic bacteria Stenotrophomonas maltophilia, named as LZMBW216, were isolated and identified from the potato (Solanum tuberosum L. cv. Da Xi Yang) leaf surface. They could decrease primary root elongation and lateral root numbers in Arabidopsis seedlings. The inhibitory effects of LZMBW216 on plant growth were not due to a reduced indole-3-acetic acid (IAA) content, as exogenously applied IAA did not recover the inhibition. Furthermore, LZMBW216 did not affect the expression of DR5::GUS and CycB1;1::GUS. However, we found that LZMBW216 exhibited little effect on the primary root elongation in the pin2 mutant and on the lateral root numbers in the aux1-7 mutant. Moreover, LZMBW216 decreased expressions of AUX1 and PIN2 proteins. Together, these results suggest that root system architecture alterations caused by LZMBW216 may involve polar auxin transport.

Plant cell lines represent useful models in plant cell biology. They allow simple analysis of the effects of various factors including modulated gene expression at cellular and subcellular levels. The tobacco BY-2 cell line is a favoured model due to its high proliferation rate, capability of effective synchronization, and accessibility to transformation. A relatively high uniformity of BY-2 cultures allows morphological phenotyping and assessment of growth parameters like mitotic index, viability, or cell density. Here we review already published and newly introduced optimized guidelines to carry out reliable, reproducible and efficient characterization of BY-2 cultures from suggestions of appropriate methods to acquire primary data, proper statistical treatment, and biological interpretation. The presented experimental data demonstrate the extent of natural variability and the effect of initial cell density on various cell culture features. Supportive equations allow to estimate some derived phenotypic parameters like cell cycle duration or fresh biomass of the culture and to determine the size of data sets for reliable documentation of a certain phenotypic change. The optimized protocols and accompanying discussion of weak points of different approaches should serve as practical guide for both beginners and experienced researchers working on BY-2 cells.

The WRKY belongs to an important plant specific transcription factor families which are involved in response to various environmental stresses, as well as in growth and developmental processes. In the present report, a genome-wide identification and characterization of WRKY gene family in barley led to revision of HvWRKYs to 93 members. The phylogenetic tree was also reconstructed based on the full-length WRKY protein sequences in barley and Arabidopsis. HvWRKYs were classified into three major groups (I, II, and III) and group II was further divided to 5 subgroups (a to e). HvWRKYs were named after this classification. Interestingly, some specific motifs were discovered in subgroups IIa, IIb, and III. Analyzing the available microarray data revealed eight candidate WRKY genes which were up-regulated under drought and salinity stresses compared to the optimum conditions at seedling stage in barley. Expression profiles of these WRKY genes were validated by quantitative real-time PCR. All the investigated candidate genes (HvWRKY_IIc2, HvWRKY_III11, HvWRKY_IIb2, HvWRKY_IId4, HvWRKY_III23, HvWRKY_IIa5 and HvWRKY_IIc19) except for HvWRKY_I8 were significantly up-regulated by drought stress at the seedling stage in drought-tolerant genotype, indicating their role in drought tolerance. We hope the presented information would be helpful toward achieving drought tolerant cultivars through genetic engineering or molecular breeding.

Maize is an important crop and its nitrogen use efficiency (NUE) has been an issue for plant scientists and breeders for many years. To meet the demand of genetic diversity in cultivating local elite maize cultivars, researchers need to isolate germplasms with a high NUE. In this study, 30 maize inbred lines were screened under hydroponic conditions, and three inbred lines that tolerate low nitrogen concentration were identified. A comparative analysis of genes involved in N uptake, transport, and assimilation between two lines with different tolerances revealed that the low-nitrogen-tolerant inbred line MBST exhibited higher expressions of nitrate and ammonium transporters, especially ZmNRT3.1B, than less tolerant B73. This suggests that the MBST line had a more efficient high-affinity transporter system. We also showed that low-nitrogen conditions down-regulated the expressions of master genes, ZmNLPs, which were negatively correlated with the expressions of the nitrate transporters ZmNRTs. This indicates the existence of regulators that antagonize the function of ZmNLPs. Some genes related to N assimilation and carbon metabolism were also more expressed in MBST. This research shows that the low-nitrogen-tolerant line, MBST, transported nitrate and ammonium more effectively than the B73 line. The NUE was also higher in MBST than in B73.

It is well known that phloem is essential for transporting proteins as long-distance signals. In this study, a proteomic approach was carried out to identify proteins accumulated in phloem exudates at the pre-floral induction (PFId) stage, at the floral induction (FId) stage, and at the floral initiation (FIn) stage. As a result, 45 phloem exudate proteins were detected. Six proteins were found at all three stages. Sixteen proteins were specific to the PFId stage, 14 proteins were specific to the FId and FIn stages. From the enriched gene ontology (GO)-terms related to transport, signaling, hormone, and development, 12 transport-related, 5 signaling-related, 10 hormone-related, and 9 development-related proteins were identified. It was found that arginine glycine glycine repeats nuclear RNA binding protein A (RGGA) was specific to the FId stage whereas heat shock protein 90-7, plasma membrane intrinsic protein 1-4, and the homolog protein encoded by At4g27190 were specific to the FIn stage. The relative abundances of sporulation protein F10D13.7 and ATP-dependent binding casette transporter G family member 37 were higher at the FId stage than at the PFId stage, and that of enolase 2 was higher at the FIn stage than at the PFId stage, suggesting that these phloem exudate proteins might act as long-distance signals involved in the transition from vegetative growth to reproductive growth in litchi. This study contributes to the comparative proteomic analysis of plant phloem sap, which will provide insights into proteins involved in floral induction as well as inter-organ communication during development in litchi.

Chilling stress is a major abiotic factor that limits the growth and productivity of melon (Cucumis melo L.). The application of nitric oxide (NO) can enhance plant tolerance to chilling stress; however, the underlying molecular mechanisms for this process remain poorly understood. In this study, RNA sequencing was performed on melon seedlings exposed to control conditions, chilling stress, or chilling stress in the presence of NO donor sodium nitroprusside (SNP), to identify NO-mediated transcript changes in response to chilling stress. The results identified 488, 1 012, and 1 589 differentially expressed genes (DEGs) between plants in optimum conditions (CK) and chilling stress (CS) groups, plants in the CS and chilling stress + SNP (CN) groups, and those in CK and CN groups, respectively. Through gene ontology (GO) database and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses, the DEGs were classified as predominantly involved in saccharide metabolism, biosynthesis of other secondary metabolites, lipid metabolism, amino-acid metabolism, and signal transduction pathways. In addition, 39 genes related to sugar metabolism including those encoding UDP-glucuronate-4-epimerase, β-glucosidase, glucuronosyltransferase, α-1,4-galacturonosyl transferase, and hexokinase, were upregulated in the CK vs. CS comparison, and genes encoding fructose-bisphosphate aldolase and glucan-endo-1,3-β-glucosidase were upregulated in the CS vs. CN, and CK vs. CN comparisons. A gene encoding an EREBP-like factor was upregulated in the CK vs. CS, CS vs. CN, and CK vs. CN comparisons. The expression profiles of 10 selected genes were analyzed using real-time quantitative PCR, and the candidate gene expression patterns were consistent with the DEG classification from RNA-seq. Overall, the data provide insight into the transcriptional regulation by exogenous NO in the response of melon seedlings to chilling stress. The data from this study are relevant for further research on the molecular mechanisms that underlie chilling resistance in melon plants.

Morphological traits of seeds of Festulolium braunii (K. Richt.) A. Camus cultivars were studied in relation to weather conditions. The obtained results show that morphological traits of seeds varied among cultivars and years of cultivation. The values of seed characteristics were higher in year 2016 due to more favorable weather conditions for plant growth. It was found that the husked seeds of Festulolium cultivars were characterized by a similar length and width regardless of the year, whereas naked seeds significantly differed in these characteristics. Mean values (from the research years) of seed parameters, such as thousand seed mass, area, convex area, shape factor, rectangle, as well as naked seed width showed variations among cultivars. At the same time, it was found that the mass of 1 000 seeds of individual cultivars showed the smallest variability in both years of the study (2.56 - 4.86 %) indicating a high stability of this trait. Thousand seed mass was significantly correlated with husked seed length / husked seed width ratio and husked seed length, and weakly correlated with yield.

Dormancy is important for the pear (Pyrus pyrifolia) to survive a harsh environment. The molecular base of dormancy in pear, especially in some local cultivars, is still unclear. Genome-wide transcriptome analysis in flower buds of cv. Huangli (an excellent local cultivar native to Guizhou mountain area in China) was conducted to explore the mechanism regulating bud dormancy in pear. For the release of endo-dormancy 223 chilling hours (CHs) was needed in Huangli flower buds, which was less than in commercial cultivars. Comparisons of transcript amounts among seven dates during dormancy (30 Oct. vs. 15 Nov., 15 Nov. vs. 30 Nov., 30 Nov. vs. 15 Dec., 15 Dec. vs. 30 Dec., 30 Dec. vs. 15 Jan., and 15 Jan vs. 15 Feb.), resulted in the detection of 1 064, 1 057, 541, 412, 577, and 3 814 differentially expressed transcripts, respectively. The reference genome of pear was used to align the RNA-Seq reads and to measure the transcript expression. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) were then used to annotate the transcript descriptions and to assign a pathway to each transcript. The results revealed, that secondary metabolite biosynthesis, especially phenylpropanoid biosynthesis pathway, was the most enriched pathway out of 132 pathways. These interesting results indicated that dormancy in Huangli might be regulated mainly by secondary metabolite biosynthesis pathway, and the two continuous dormant stages (endo-dormancy and eco-dormancy) might be regulated specifically by phenylpropanoid biosynthesis and plant hormone signal transduction, respectively.

The effects of exogenous nitric oxide (NO) and ethylenediaminetetraacetic acid (EDTA) on cadmium toxicity and accumulation in ryegrass (Lolium perenne L.) were studied in a hydroponic experiment. The results show that in plants without Cd application, addition of EDTA and sodium nitroprusside (SNP, an exogenous NO donor) significantly reduced the plant height, root length, and root activity of ryegrass, and significantly increased the O₂^*- generation rate and H₂O₂ and malondialdehyde (MDA) content in the aboveground and underground parts of ryegrass. Cadmium stress significantly inhibited ryegrass growth. Addition of SNP or EDTA alleviated Cd toxicity, and addition of both had a better effect. Compared with Cd alone, the shoot height and root length in the Cd+EDTA+SNP treatment increased by 68.8 and 59.6 %, and plant fresh and dry masses by 62.6 and 60.0 %, respectively. Also, the superoxide dismutase activity in the shoots and roots increased by 32.5 and 67.6 %, the peroxidase activity by 49.8 and 67.6 %, the ascorbate peroxidase activity by 134 and 102 %, the MDA content decreased by 30.4 and 21.8 %, and the O₂^*- generation rate by 29.0 and 26.1 %, respectively. At the same time, Cd content in the shoots and roots increased significantly by 89.7 and 30.2 %, respectively. Overall, the results suggest that exogenous NO could enhance Cd tolerance of ryegrass, but addition of EDTA could promote plant Cd uptake. Combined application of NO and EDTA increased Cd accumulation in the aboveground parts of ryegrass. In this experiment, the treatment of 100 µM CdCl₂ + 0.25 mM EDTA + 50 μM SNP showed the best effects in promoting Cd accumulation in ryegrass and enhancing its Cd tolerance.

Interspecific and intergeneric hybridization within the Festuca-Lolium complex is frequently used in forage plant breeding. However, little is known about the natural occurrence and competitiveness of such hybrids. We collected naturally formed hybrids between Festuca apennina, Festuca pratensis, and Lolium perenne in different habitats of Switzerland and the British Isles and studied their origin, the ease of their spontaneous formation, and their competitiveness with parental species. A special attention was paid to the largely sterile triploid forms and their rare sexual progeny. The triploid hybrid F. apennina × F. pratensis proved to be widespread and often highly competitive in Swiss permanent pastures. The majority of these hybrids originated from F. apennina as the seed parent although little or no F. apennina grew nearby. In an experimental setting with ample F. pratensis pollen provided by neighbouring plants, up to 20 % of seeds from open pollinated F. apennina plants were interspecific hybrids; among seeds collected in natural habitats, only 0.35 % were hybrids. At an experimental site at 1 000 m altitude, these triploid hybrids grew much more vigorously than corresponding tetraploid pure F. apennina, confirming their great competitiveness at such altitudes in permanent grasslands. The triploid hybrids were only marginally fertile suggesting that vegetative propagation by rhizomes is the cause of their competitive success in grassland. Moreover, triploid progeny retained the chromosome constitution of their mother plants indicating the possibility of apomixis. Natural triploid F. pratensis × L. perenne hybrids were partially female fertile (a seed set of 0.1 % or less) whereas diploid hybrids did not produce any viable seeds. Progenies of these triploids showed considerable chromosome alterations, such as loss of a genome or recombination due to homoeologous pairing, and only rarely the chromosome constitution of the triploid mother plant was retained. It was concluded that natural triploid interspecific hybrids could expand the range of their progenitor species and might function as bridges transferring genes between them.