Bio-control of soil-borne virus infection by seed application of Glycyrrhiza glabra extract and the rhamnolipid Rhapynal.

MAIN CONCLUSION: Seed-application of the natural products protects sugar beet and wheat plants against infection with plasmodiophorid-transmitted viruses and thus may represent an efficient, environmentally friendly, easy and cost effective biocontrol strategy. In times of intensive agriculture, resource shortening and climate change, alternative, more sustainable and eco-friendly plant protection strategies are required. Here, we tested the potential of the natural plant substances Glycyrrhiza glabra leaf extract (GE) and the rhamnolipid Rhapynal (Rha) applied to seeds to protect against infection of sugar beet and wheat with soil-borne plant viruses. The soil-borne Polymyxa betae- and Polymyxa graminis-transmitted viruses cause extensive crop losses in agriculture and efficient control strategies are missing. We show that GE and Rha both efficiently protect plants against infection with soil-borne viruses in sugar beet and wheat when applied to seeds. Moreover, the antiviral protection effect is independent of the cultivar used. No protection against Polymyxa sp. was observed after seed treatment with the bio-substances at our analysis time points. However, when we applied the bio-substances directly to soil a significant anti-Polymyxa graminis effect was obtained in roots of barley plants grown in the soil as well as in the treated soil. Despite germination can be affected by high concentrations of the substances, a range of antiviral protection conditions with no effect on germination were identified. Seed-treatment with the bio-substances did not negatively affect plant growth and development in virus-containing soil, but was rather beneficial for plant growth. We conclude that seed treatment with GE and Rha may represent an efficient, ecologically friendly, non-toxic, easy to apply and cost efficient biocontrol measure against soil-borne virus infection in plants.

Zinc and methyl jasmonate improve sugar beet tolerance to high boron stress by enhanced leaf photochemical performance.

Nutrient imbalances, such as high boron (B) stress, occur within, as well as across, agricultural systems worldwide and have become an important abiotic factor that reduces soil fertility and inhibits plant growth. Sugar beet is a B-loving crop and is better suited to be grown in high B environments, but the methods and mechanisms regarding the enhancement of high-B stress tolerance traits are not clear. The main objective of this research was to elucidate the effects of the alone and/or combined foliar spraying of zinc sulfate (ZnSO4) and methyl jasmonate (MeJA) on the growth parameters, tolerance, and photochemical performance of sugar beet under high-B stress. Results demonstrated that the photosynthetic performance was inhibited under high-B stress, with a reduction of 11.33% in the net photosynthetic rate (Pn) and an increase of 25.30% in the tolerance index. The application of ZnSO4, MeJA, and their combination enhanced sugar beet's adaptability to high-B stress, with an increase in Pn of 9.22%, 4.49%, and 2.85%, respectively, whereas the tolerance index was elevated by 15.33%, 8.21%, and 5.19%, respectively. All three ameliorative treatments resulted in increased photochemical efficiency (Fv/Fm) and the photosynthetic performance index (PIABS) of PSII. Additionally, they enhanced the light energy absorption (ABS/RC) and trapping capacity (DIO/RC), reduced the thermal energy dissipation (TRO/RC), and facilitated the QA to QB transfer in the electron transport chain (ETC) of PSII, which collectively improved the photochemical performance. Therefore, spraying both ZnSO4 and MeJA can better alleviate high-B stress and promote the growth of sugar beet, but the combined spraying effect of ZnSO4 and MeJA is lower than that of individual spraying. This study provides a reference basis for enhancing the ability of sugar beet and other plants to tolerate high-B stress and for sugar beet cultivation in high B areas.

Effect of BvAgNP on growth, development, and glyoxalase gene expression analysis in Mammillaria bombycina and Selenicereus undatus.

BACKGROUND: Silver nanoparticles (AgNPs) have been used in plant tissue culture as growth stimulants, promoting bud initiation, germination, and rooting. In prior studies, AgNPs were synthesized and characterized by green synthesis using extracts from Beta vulgaris var. cicla (BvAgNP), and their functionality as seed disinfectant and antimicrobial was verified. In this study, we evaluated the effect of BvAgNP on the growth and development of Mammillaria bombycina and Selenicereus undatus in vitro, as well as the expression of glyoxalase genes. METHODS: Explants from M. bombycina and S. undatus in vitro were treated with 25, 50, and 100 mg/L of BvAgNP. After 90 days, morphological characteristics were evaluated, and the expression of glyoxalase genes was analyzed by qPCR. RESULTS: All treatments inhibited rooting for M. bombycina and no bud initiation was observed. S. undatus, showed a maximum response in rooting and bud generation at 25 mg/L of BvAgNP. Scanning electron microscopy (SEM) results exhibited a higher number of vacuoles in stem cells treated with BvAgNP compared to the control for both species. Expression of glyoxalase genes in M. bombycina increased in all treatments, whereas it decreased for S. undatus, however, increasing in roots. CONCLUSIONS: This study presents the effects of BvAgNP on the growth and development of M. bombycina and S. undatus, with the aim of proposing treatments that promote in vitro rooting and bud initiation.

Exogenous putrescine attenuates the negative impact of drought stress by modulating physio-biochemical traits and gene expression in sugar beet (Beta vulgaris L.).

Drought tolerance is a complex trait controlled by many metabolic pathways and genes and identifying a solution to increase the resilience of plants to drought stress is one of the grand challenges in plant biology. This study provided compelling evidence of increased drought stress tolerance in two sugar beet genotypes when treated with exogenous putrescine (Put) at the seedling stage. Morpho-physiological and biochemical traits and gene expression were assessed in thirty-day-old sugar beet seedlings subjected to drought stress with or without Put (0.3, 0.6, and 0.9 mM) application. Sugar beet plants exposed to drought stress exhibited a significant decline in growth and development as evidenced by root and shoot growth characteristics, photosynthetic pigments, antioxidant enzyme activities, and gene expression. Drought stress resulted in a sharp increase in hydrogen peroxide (H2O2) (89.4 and 118% in SBT-010 and BSRI Sugar beet 2, respectively) and malondialdehyde (MDA) (35.6 and 27.1% in SBT-010 and BSRI Sugar beet 2, respectively). These changes were strongly linked to growth retardation as evidenced by principal component analysis (PCA) and heatmap clustering. Importantly, Put-sprayed plants suffered from less oxidative stress as indicated by lower H2O2 and MDA accumulation. They better regulated the physiological processes supporting growth, dry matter accumulation, photosynthetic pigmentation and gas exchange, relative water content; modulated biochemical changes including proline, total soluble carbohydrate, total soluble sugar, and ascorbic acid; and enhanced the activities of antioxidant enzymes and gene expression. PCA results strongly suggested that Put conferred drought tolerance mostly by enhancing antioxidant enzymes activities that regulated homeostasis of reactive oxygen species. These findings collectively provide an important illustration of the use of Put in modulating drought tolerance in sugar beet plants.

A Comparison of the Effect of Lead (Pb) on the Slow Vacuolar (SV) and Fast Vacuolar (FV) Channels in Red Beet (Beta vulgaris L.) Taproot Vacuoles.

Little is known about the effect of lead on the activity of the vacuolar K+ channels. Here, the patch-clamp technique was used to compare the impact of lead (PbCl2) on the slow-activating (SV) and fast-activating (FV) vacuolar channels. It was revealed that, under symmetrical 100-mM K+, the macroscopic currents of the SV channels exhibited a typical slow activation and a strong outward rectification of the steady-state currents, while the macroscopic currents of the FV channels displayed instantaneous currents, which, at the positive potentials, were about three-fold greater compared to the one at the negative potentials. When PbCl2 was added to the bath solution at a final concentration of 100 µM, it decreased the macroscopic outward currents of both channels but did not change the inward currents. The single-channel recordings demonstrated that cytosolic lead causes this macroscopic effect by a decrease of the single-channel conductance and decreases the channel open probability. We propose that cytosolic lead reduces the current flowing through the SV and FV channels, which causes a decrease of the K+ fluxes from the cytosol to the vacuole. This finding may, at least in part, explain the mechanism by which cytosolic Pb2+ reduces the growth of plant cells.

Production of Homozygous Red Beet (Beta vulgaris L. subsp. vulgaris) Plants by Ovule Culture.

Hybrid varieties dominate the red beet market. The breeding process necessary to produce these cultivars is very difficult and time consuming. The application of in vitro gynogenesis can reduce the time needed to produce the corresponding homozygous pure lines to a few months. Our research team has developed a method to obtain red beet doubled haploid plants by gynogenesis. The best medium for gynogenesis induction is the B5 medium with the addition of 0.5 mg/L IAA, 0.2 mg/L BA, and 322 mg/L putrescine, whereas the best medium for shoot induction from embryos proved to be the MS medium supplemented with 0.1 mg/L NAA, 0.1 mg/L BA, and 0.5 mg/L putrescine. The shoots obtained were rooted on MS medium containing half the concentration of microelements and 3 mg/L NAA, 160 mg/L putrescine, and 20 g/L sucrose. Ploidy evaluation of gynogenetic plants was performed by flow cytometry and homozygosity or heterozygosity was determined by two isoenzymatic systems: PGI and AAT.

The RsRlpA Effector Is a Protease Inhibitor Promoting Rhizoctonia solani Virulence through Suppression of the Hypersensitive Response.

Rhizoctonia solani (Rs) is a soil-borne pathogen with a broad host range. This pathogen incites a wide range of disease symptoms. Knowledge regarding its infection process is fragmented, a typical feature for basidiomycetes. In this study, we aimed at identifying potential fungal effectors and their function. From a group of 11 predicted single gene effectors, a rare lipoprotein A (RsRlpA), from a strain attacking sugar beet was analyzed. The RsRlpA gene was highly induced upon early-stage infection of sugar beet seedlings, and heterologous expression in Cercospora beticola demonstrated involvement in virulence. It was also able to suppress the hypersensitive response (HR) induced by the Avr4/Cf4 complex in transgenic Nicotiana benthamiana plants and functioned as an active protease inhibitor able to suppress Reactive Oxygen Species (ROS) burst. This effector contains a double-psi beta-barrel (DPBB) fold domain, and a conserved serine at position 120 in the DPBB fold domain was found to be crucial for HR suppression. Overall, R. solani seems to be capable of inducing an initial biotrophic stage upon infection, suppressing basal immune responses, followed by a switch to necrotrophic growth. However, regulatory mechanisms between the different lifestyles are still unknown.

Exogenous allantoin improves the salt tolerance of sugar beet by increasing putrescine metabolism and antioxidant activities.

Allantoin as a nitrogen metabolite can improve the salt tolerance in plants, but its mechanism of action remain elusive. Herein, the effects of pretreatment with exogenous allantoin in salt tolerance were investigated in sugar beet. The seedlings were subjected to salt stress (300 mM Na+) without or with different allantoin concentrations (0.01, 0.1, and 1 mM). The effects of allantoin on plant growth, homeostasis, oxidative damage, osmoregulation, and polyamine metabolism were studied. The results showed that salt stress inhibited the net photosynthetic rate and plant growth, and caused oxidative damage. However, these adverse effects were mitigated by exogenous allantoin in a dose-dependent manner, especially at 0.1 mM. Allantoin reduced the accumulation of ROS by increasing the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and AsA content. Under salt stress, allantoin reduced the root concentrations of free putrescine (Put) but increased the free spermine (Spm) in leaves and roots. Furthermore, allantoin decreased the Na+/K+ ratio and promoted the accumulation of betaine and soluble sugars in leaves and roots. Under salinity conditions, allantoin may enhance the antioxidant system and improve ion homeostasis by enhancing putrescine and/or spermine accumulation. In addition, Pearson's correlation and principal component analysis (PCA) established correlations between physiological parameters, and significant differences between different concentrations of allantoin were observed. In total, exogenous allantoin effectively reduced the oxidative damage and ion toxicity in sugar beet, caused by salinity, this finding would be helpful in improving salt tolerance in plant.

Effect of Auxin (IAA) on the Fast Vacuolar (FV) Channels in Red Beet (Beta vulgaris L.) Taproot Vacuoles.

In contrast to the well-studied effect of auxin on the plasma membrane K+ channel activity, little is known about the role of this hormone in regulating the vacuolar K+ channels. Here, the patch-clamp technique was used to investigate the effect of auxin (IAA) on the fast-activating vacuolar (FV) channels. It was found that the macroscopic currents displayed instantaneous currents, which at the positive potentials were about three-fold greater compared to the one at the negative potentials. When auxin was added to the bath solution at a final concentration of 1 µM, it increased the outward currents by about 60%, but did not change the inward currents. The imposition of a ten-fold vacuole-to-cytosol KCl gradient stimulated the efflux of K+ from the vacuole into the cytosol and reduced the K+ current in the opposite direction. The addition of IAA to the bath solution with the 10/100 KCl gradient decreased the outward current and increased the inward current. Luminal auxin reduced both the outward and inward current by approximately 25% compared to the control. The single channel recordings demonstrated that cytosolic auxin changed the open probability of the FV channels at the positive voltages to a moderate extent, while it significantly increased the amplitudes of the single channel outward currents and the number of open channels. At the positive voltages, auxin did not change the unitary conductance of the single channels. We suggest that auxin regulates the activity of the fast-activating vacuolar (FV) channels, thereby causing changes of the K+ fluxes across the vacuolar membrane. This mechanism might serve to tightly adjust the volume of the vacuole during plant cell expansion.

Mechanisms of Sugar Beet Response to Biotic and Abiotic Stresses.

Sugar beet is used not only in the sugar production, but also in a wide range of industries including the production of bioethanol as a source of renewable energy, extraction of pectin and production of molasses. The red beetroot has attracted much attention as health-promoting and disease-preventing functional food. The negative effects of environmental stresses, including abiotic and biotic ones, significantly decrease the cash crop sugar beet productivity. In this paper, we outline the mechanisms of sugar beet response to biotic and abiotic stresses at the levels of physiological change, the genes' functions, transcription and translation. Regarding the physiological changes, most research has been carried out on salt and drought stress. The functions of genes from sugar beet in response to salt, cold and heavy metal stresses were mainly investigated by transgenic technologies. At the transcriptional level, the transcriptome analysis of sugar beet in response to salt, cold and biotic stresses were conducted by RNA-Seq or SSH methods. At the translational level, more than 800 differentially expressed proteins in response to salt, K+/Na+ ratio, iron deficiency and resupply and heavy metal (zinc) stress were identified by quantitative proteomics techniques. Understanding how sugar beet respond and tolerate biotic and abiotic stresses is important for boosting sugar beet productivity under these challenging conditions. In order to minimize the negative impact of these stresses, studying how the sugar beet has evolved stress coping mechanisms will provide new insights and lead to novel strategies for improving the breeding of stress-resistant sugar beet and other crops.

Transcriptome Analysis of Salt-Sensitive and Tolerant Genotypes Reveals Salt-Tolerance Metabolic Pathways in Sugar Beet.

Soil salinization is a common environmental problem that seriously affects the yield and quality of crops. Sugar beet (Beta vulgaris L.), one of the main sugar crops in the world, shows a strong tolerance to salt stress. To decipher the molecular mechanism of sugar beet under salt stress, we conducted transcriptomic analyses of two contrasting sugar beet genotypes. To the best of our knowledge, this is the first comparison of salt-response transcriptomes in sugar beet with contrasting genotypes. Compared to the salt-sensitive cultivar (S710), the salt-tolerant one (T710MU) showed better growth and exhibited a higher chlorophyll content, higher antioxidant enzyme activity, and increased levels of osmotic adjustment molecules. Based on a high-throughput experimental system, 1714 differentially expressed genes were identified in the leaves of the salt-sensitive genotype, and 2912 in the salt-tolerant one. Many of the differentially expressed genes were involved in stress and defense responses, metabolic processes, signal transduction, transport processes, and cell wall synthesis. Moreover, expression patterns of several genes differed between the two cultivars in response to salt stress, and several key pathways involved in determining the salt tolerance of sugar beet, were identified. Our results revealed the mechanism of salt tolerance in sugar beet and provided potential metabolic pathways and gene markers for growing salt-tolerant cultivars.

Beetroot mineral composition affected by mineral and organic fertilization.

In modern agriculture, besides providing high and stable yields, it is imperative to produce products with a high nutritive quality. The goal of this study was to determine the effect of different fertilization regimes on the macro- and micronutrients in beetroot. A 3-year field trial was set up according to a Latin square method with four types of fertilization (unfertilized control, 50 t stable manure ha-1, and 500 and 1,000 kg NPK 5-20-30 ha-1). The mineral content was determined as follows (mg 100 g-1 in fresh weight of beetroot): 14-29 P, 189-354 K, 18-34 Ca, 17-44 Mg, 0.67-1.83 Fe, 0.41-0.65 Mn and 0.28-0.44 Zn. The highest beetroot P content was determined for the treatment with stable manure, especially in a year with dry climatic conditions. The highest beetroot K content was determined for the treatment with 1,000 kg NPK 5-20-30 ha-1, but at the same time for the same treatment, a general decreasing trend of micronutrient content was determined, due to the possible antagonistic effect of added potassium. For better mineral status of beetroot, application of combined mineral and organic fertilizers supplemented with additional foliar application of micronutrients can be suggested.

Genome-wide identification, characterization, and expression patterns of the BZR transcription factor family in sugar beet (Beta vulgaris L.).

BACKGROUND: BRASSINAZOLE-RESISTANT (BZR) family genes encode plant-specific transcription factors (TFs) that participate in brassinosteroid signal transduction. BZR TFs have vital roles in plant growth, including cell elongation. However, little is known about BZR genes in sugar beet (Beta vulgaris L.). RESULTS: Therefore, we performed a genome-wide investigation of BvBZR genes in sugar beet. Through an analysis of the BES1_N conserved domain, six BvBZR gene family members were identified in the sugar beet genome, which clustered into three subgroups according to a phylogenetic analysis. Each clade was well defined by the conserved motifs, implying that close genetic relationships could be identified among the members of each subfamily. According to chromosomal distribution mapping, 2, 1, 1, 1, and 1 genes were located on chromosomes 1, 4, 5, 6, and 8, respectively. The cis-acting elements related to taproot growth were randomly distributed in the promoter sequences of the BvBZR genes. Tissue-specific expression analyses indicated that all BvBZR genes were expressed in all three major tissue types (roots, stems, and leaves), with significantly higher expression in leaves. Subcellular localization analysis revealed that Bv1_fxre and Bv6_nyuw are localized in the nuclei, consistent with the prediction of Wolf PSORT. CONCLUSION: These findings offer a basis to predict the functions of BZR genes in sugar beet, and lay a foundation for further research of the biological functions of BZR genes in sugar beet.

Cysteine enhances the content of betalains and polyphenols in fresh-cut red beet.

This study investigated the effectiveness of cysteine in conservation of bioactive compounds and the antioxidant capacity of minimally processed red beet. After red beet minimal processing increasing cysteine concentrations were applied, corresponding to control, 2 mM, 4 mM, 8 mM and 16 mM. Assay was performed over 15 d to evaluate the polyphenols, betalains, antioxidant capacity and enzymatic activity of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL). Cysteine enhanced the gallic acid, caffeic acid, chlorogenic acid, kaempferol and betalain contents until 6 d of storage. Subsequently, dosages of cysteine above 4 mM maintained gallic acid, kaempferol and betalains contents. Cysteine appears to influence the phenylpropanoid pathway, favoring the accumulation of polyphenols and betalains. In red beet, cysteine did not inhibit PPO activity but enhanced PAL activity. Betalains contribute more than phenolics to the antioxidant capacity, and their relationship with cysteine has not been thoroughly elucidated to date.

Fate of Glyphosate during Production and Processing of Glyphosate-Resistant Sugar Beet ( Beta vulgaris).

Glyphosate is a widely used herbicide in commercial crop production for both conventional and herbicide-resistant crops. Herbicide-resistant crops, like glyphosate-resistant sugar beet, are often exposed to multiple applications of glyphosate during the growing season. The fate of this herbicide in resistant crops has not been publicly documented. We investigated the fate of glyphosate and main metabolite aminomethylphosphonic acid in glyphosate-resistant sugar beet grown in northern Colorado. Glyphosate residues were measured via directed ultra-high-performance liquid chromatography tandem mass spectrometry analysis of sugar beet shoots and roots throughout the growing season, from samples collected at various steps during sugar beet processing, and from flow-through samples of greenhouse-grown beets. Sugar beet rapidly absorbed glyphosate after foliar application, and subsequently translocated the herbicide to its roots, with between 2 and 3 µg/g fresh weight measured in both tissue types within 1 week of application. However, only trace amounts of glyphosate remained in either the shoots or the roots 2 weeks after application. Analysis of irrigation flow-through in pot assays confirmed that the herbicide readily exuded out of the roots. Processing of the beets removed glyphosate and herbicide levels were below the limit of detection in the crystalline sugar final product.

A slow release brown coal-urea fertiliser reduced gaseous N loss from soil and increased silver beet yield and N uptake.

Increasing crop yield and fertiliser nitrogen (N)-use efficiency is important for productive agricultural systems with a reduced environmental footprint. The aim of this study was to assess the effect of slow release brown coal-urea (BCU) fertiliser on the gaseous N losses, biomass yield and N uptake by silver beet (Beta vulgaris L.) compared to commercial urea. Two soils were amended with urea, BCU 1 (22% N) or BCU 2 (17% N) as N-fertiliser at the rate of 50 or 100 kg N ha-1. Five gas sampling periods were undertaken to measure the loss of N as N2O and NH3. After 10 weeks, biomass, N concentration, and N uptake of silver beet, and mineral and mineralisable N of post-harvest soil were measured. BCU substantially increased fertiliser N availability and uptake by silver beet, reduced N2O emission by 29% and NH3 emission by 36% compared to urea alone, irrespective of soil type. Compared to urea, BCU blends increased biomass yield by 27% and 23% in a Tenosol and Dermosol soil, respectively. In addition, application of BCU fertiliser substantially enhanced the potentially mineralisable N and organic carbon content of soil. These results provide evidence that granulation of urea with brown coal (BC) can increase silver beet N-use efficiency and yield in different soil types, and more work is now required to validate this technology for other crops.

Preharvest application of ethephon and postharvest UV-B radiation improve quality traits of beetroot (Beta vulgaris L. ssp. vulgaris) as source of colourant.

BACKGROUND: Betanins have become excellent replacers for artificial red-purple food colourants. Red beet (Beta vulgaris L. spp. vulgaris) known as beetroot, is a rich source of betalains, which major forms are betanin (red to purple) and vulgaxanthin (yellow). Betalains and phenolic compounds are secondary metabolites, accumulation of which is often triggered by elicitors during plant stress responses. In the present study, pre-harvest applications of ethephon (an ethylene-releasing compound) and postharvest UV-B radiation were tested as elicitors of betalains and phenolic compounds in two beetroot cultivars. Their effects on quality parameters were investigated, and the expression of biosynthetic betalain genes in response to ethephon was determined. RESULTS: Ethephon was applied as foliar spray during the growth of beetroot, resulting in increased betanin (22.5%) and decreased soluble solids contents (9.4%), without detrimental effects on beetroot yield. The most rapid accumulation rate for betanin and soluble solids was observed between 3 and 6 weeks after sowing in both untreated and ethephon-treated beetroots. Overall, the expression of the betalain biosynthetic genes (CYP76AD1, CYP76AD5, CYP76AD6 and DODA1), determining the formation of both betanin and vulgaxanthin, increased in response to ethephon treatment, as did the expression of the betalain pathway activator BvMYB1. In the postharvest environment, the use of short-term UV-B radiation (1.23 kJ m- 2) followed by storages for 3 and 7 days at 15 °C resulted in increased betanin to vulgaxanthin ratio (51%) and phenolic content (15%). CONCLUSIONS: The results of this study provide novel strategies to improve key profitability traits in betalain production. High betanin concentration and high betanin to vulgaxanthin ratio increase the commercial value of the colourant product. In addition, lowering soluble solids levels facilitates higher concentration of beetroot colour during processing. Moreover, we show that enhanced betanin content in ethephon-treated beetroots is linked to increased expression of betalain biosynthetic genes.

iTRAQ-Based Comparative Proteomic Analysis Provides Insights into Molecular Mechanisms of Salt Tolerance in Sugar Beet (Beta vulgaris L.).

Salinity is one of the major abiotic stress factors that limit plant growth and crop yield worldwide. To understand the molecular mechanisms and screen the key proteins in response of sugar beet (Beta vulgaris L.) to salt, in the present study, the proteomics of roots and shoots in three-week-old sugar beet plants exposed to 50 mM NaCl for 72 h was investigated by isobaric Tags for Relative and Absolute Quantitation (iTRAQ) technology. The results showed that 105 and 30 differentially expressed proteins (DEPs) were identified in roots and shoots of salt-treated plants compared with untreated plants, respectively. There were 46 proteins up-regulated and 59 proteins down-regulated in roots; and 13 up-regulated proteins and 17 down-regulated proteins found in shoots, respectively. These DEPs were mainly involved in carbohydrate metabolism, energy metabolism, lipid metabolism, biosynthesis of secondary metabolites, transcription, translation, protein folding, sorting, and degradation as well as transport. It is worth emphasizing that some novel salt-responsive proteins were identified, such as PFK5, MDH, KAT2, ACAD10, CYP51, F3H, TAL, SRPR, ZOG, V-H⁺-ATPase, V-H⁺-PPase, PIPs, TIPs, and tubulin α-2/ß-1 chain. qRT-PCR analysis showed that six of the selected proteins, including BvPIP1-4, BvVP and BvVAP in root and BvTAL, BvURO-D1, and BvZOG in shoot, displayed good correlation between the expression levels of protein and mRNA. These novel proteins provide a good starting point for further research into their functions using genetic or other approaches. These findings should significantly improve the understanding of the molecular mechanisms involved in salt tolerance of sugar beet plants.

Effects of aged ZnO NPs and soil type on Zn availability, accumulation and toxicity to pea and beet in a greenhouse experiment.

Most studies have assessed the toxicity of pristine NPs to plants without considering the likely changes that these NPs will undergo during their residence time in the soil. In this study, we assessed the effects of ZnO NPs (3, 20, and 225 mg Zn kg-1 soil) aged for a year in soil and after a previous crop on the Zn availability in soil, leaf accumulation and toxicity to green pea (Pisum sativum L.) and beet root (Beta vulgaris L). The effects were compared to bulk ZnO and ZnSO4 in two agricultural soils with different pH under greenhouse conditions. The Zn concentration in the plant leaf was 6-12-fold higher in acidic than in calcareous soil that could explain the different effects on plants caused by Zn applications depending on soil type. Thus, in acidic soil, ZnO NPs promoted ROS generation in both plant species with increases from 47% to 130%, increased the MDA content in pea up to 58 ±â€¯8% in plant exposed to ZnSO4 at 225 mg Zn kg-1 soil and altered the ratio of photosynthetic pigments in beet between 12% and 41%, suggesting distressed chloroplast constituents. In calcareous soil, the changes seemed to be related to the supply of Zn in Zn deficient soils, whose principal effect was the 20-65% decrease of ROS levels in treated plants. The available and leaf Zn concentrations did not differ among Zn sources. Likewise, ZnO NPs showed comparable toxic or stimulatory effects to ZnO bulk and Zn salt, with some exceptions where Zn ion showed the highest phytotoxicity and effectiveness as a micronutrient. According to our results, we cannot affirm that NPs pose a higher potential environmental risk than their bulk counterparts after one-year of residence time in soil.

Effect of Cuscuta campestris parasitism on the physiological and anatomical changes in untreated and herbicide-treated sugar beet.

The effects of field dodder on physiological and anatomical processes in untreated sugar beet plants and the effects of propyzamide on field dodder were examined under controlled conditions. The experiment included the following variants: N-noninfested sugar beet plants (control); I - infested sugar beet plants (untreated), and infested plants treated with propyzamide (1500 g a.i. ha-1 (T1) and 2000 g a.i. ha-1(T2)). The following parameters were checked: physiological-pigment contents (chlorophyll a, chlorophyll b, total carotenoids); anatomical -leaf parameters: thickness of epidermis, parenchyma and spongy tissue, mesophyll and underside leaf epidermis, and diameter of bundle sheath cells; petiole parameters: diameter of tracheid, petiole hydraulic conductance, xylem surface, phloem cell diameter and phloem area in sugar beet plants. A conventional paraffin wax method was used to prepare the samples for microscopy. Pigment contents were measured spectrophotometrically after methanol extraction. All parameters were measured: prior to herbicide application (0 assessment), then 7, 14, 21, 28 and 35 days after application (DAA). Field dodder was found to affect the pigment contents in untreated sugar beet plants, causing significant reductions. Conversely, reduction in the treated plants decreased 27% to 4% for chlorophyll a, from 21% to 5% for chlorophyll b, and from 28% to 5% for carotenoids (T1). Also, in treatment T2, reduction decreased in infested and treated plants from 19% to 2% for chlorophyll a, from 21% to 2% for chlorophyll b, from 23% to 3% for carotenoids and stimulation of 1% and 2% was observed 28 and 35 DAA, respectively. Plants infested (untreated) by field dodder had lower values of most anatomical parameters, compared to noninfested plants. The measured anatomical parameters of sugar beet leaves and petiole had significantly higher values in noninfested plants and plants treated with propyzamide than in untreated plants. Also, the results showed that propyzamide is an adequate herbicide for control of field dodder at the stage of early infestation.