Effect of Nitrogen Fertilizer Sources, Lead and Cadmium Pollution on Some Properties of Barley (Hordeum vulgare)

The study was conducted in the Department of biology - College of Education for Girls - University of Anbar in order to study the effect of cadmium and lead pollution and nitrogen fertilizer sources on the accumulation of heavy metals in the root, the vegetative part, yield and its components of barley (Hordeum vulgare L.) during growing season 2020-2021, Where the experiment was carried out in pots containing 20 kg of soil. The experiment was designed according to a randomized complete block design and in the order of factorial experiments with three replications. The experiment included two factors, the first factor is three concentrations of the elements lead and cadmium (0, 40, 80 mg liter -1), and the second factor is three types of nitrogen fertilizer sources are (ammonium sulfate (NH4)2SO4, ammonium nitrate NH4NO3 and urea CO(NH2)2). The experiment was planted and irrigated with the three nitrogen fertilizer sources on 1/11/2020. After 14 days of planting, heavy metals were added to the soil in the above-mentioned concentrations in the form of two batches. The weight of 1000 grains/g and the concentration of heavy elements (Pb, Cd) in the root, vegetative and grains after harvest were calculated. The results of the study showed: The barley plant had the ability to accumulate heavy elements in the different parts of the plant, and their concentration in the root system was the highest, then the vegetative system, then the grain. However, the accumulated amounts of lead were less than cadmium in the roots, as the highest concentrations of lead and cadmium in the roots were (24.78 and 37.22 mg kg-1) and (61.13 and 92.3 mg kg-1). for the concentrations (40 and 80 mg L-1) respectively.

The Effect of Water Stress on Total-Phenolic Content of Barley

Little is known about the relation between water stress and the accumulation of phenolics in plant tissues. The present study aimed to investigate the effect of water stress and maturation on the production of total-phenolics (TP) by four barley (Hordeum vulgare L.) varieties (‘Manel’, ‘Martin’, ‘Rihane’, ‘Espérance’). During three phenological stages (S-8, S-10.5, S-11), following Feekes scale, whole barley plants were pulled out of the field and separated into roots, stems, and leaves. Water extracts were prepared from plant parts and their TP contents were determined by spectrophotometer. To determine periods of water deficit (WD) at field, climatic characterization of the region was carried out. TP accumulated in barley plant and its parts under the influence of water deficit essentially at S8, which coincided with barley spring growth. However, TP content decreased when WD became more pronounced at the following stages. This response may be explained, partially by the biosynthesis of lignin from free phenols when the plant approached maturity. Results suggest that water stress stimulates the synthesis and accumulation of TP in barley tissues during active growth periods (spring growth) at S-8. This response doesn’t persist until the critical periods of WD where barley maturity favors a decrease in TP content for all plant parts. Regardless of growth stage and WD, barley accumulates preferentially phenolics in above-ground plant parts. The evolution of phenolic accumulation under water stress showed the same trends for the tested barley varieties, indicating a genetic control of phenolic production and their partitioning across plant parts.

Using Rhizosphere Phosphate Solubilizing Bacteria to Improve Barley (Hordeum vulgare) Plant Productivity

On average less than 1% of the total phosphorous present in soils is available to plants, making phosphorous one of the most limiting macronutrients for crop productivity worldwide. The aim of this work was to isolate and select phosphate solubilizing bacteria (PSB) from the barley rhizosphere, which has other growth promoting traits and can increase crop productivity. A total of 104 different bacterial isolates were extracted from the barley plant rhizosphere. In this case, 64 strains were able to solubilize phosphate in agar plates. The 24 strains exhibiting the highest solubilizing index belonged to 16 different species, of which 7 isolates were discarded since they were identified as putative phytopathogens. The remaining nine strains were tested for their ability to solubilize phosphate in liquid medium and in pot trials performed in a greenhouse. Several of the isolated strains (Advenella mimigardefordensis, Bacillus cereus, Bacillus megaterium and Burkholderia fungorum) were able to significantly improve levels of assimilated phosphate, dry weight of ears and total starch accumulated on ears compared to non-inoculated plants. Since these strains were able to increase the growth and productivity of barley crops, they could be potentially used as microbial inoculants (biofertilizers).

The TCP transcription factor HvTB2 heterodimerizes with VRS5(HvTB1) and controls spike architecture in barley

Barley is the fourth largest cereal crop grown worldwide, and essential for food and feed production. Phenotypically, the barley spike, which is unbranched, occurs in two main architectural shapes: two-rowed or six-rowed. In the 6-rowed cultivars, all three florets of the triple floret meristem develop into seeds while in 2-rowed lines only the central floret forms a seed. VRS5(HvTB1), act as inhibitor of lateral seed outgrowth and vrs5(hvtb1) mutants display a six-rowed spike architecture. VRS5(HvTB1) is a member of the TCP transcription factor (TF) family, which often form protein-protein interactions with other transcriptional regulators to modulate the expression of their target genes.Despite the key role of VRS5(HvTB1) in regulating barley plant architecture, there is hardly any knowledge on its molecular mode-of-action. We performed an extensive phylogenetic analysis of the TCP transcription factor family, followed by an in-vitro protein-protein interaction study using yeast-two-hybrid. Our analysis shows that VRS5(HvTB1) has a diverse interaction capacity, interacting with class II TCP’s, NF-Y TF, but also chromatin modellers. Further analysis of the interaction capacity of VRS5(HvTB1) with other TCP TFs shows that VRS5(HvTB1) preferably interacts with other class II TCP TFs within the TB1 clade. One of these interactors, encoded by HvTB2, shows a similar expression pattern when compared to VRS5(HvTB1). Haplotype analysis of HvTB2 suggest that this gene is highly conserved and shows hardly any variation in cultivars or wild barley. Induced mutations in HvTB2 trough CRISPR-CAS9 mutagenesis in cv. Golden Promise resulted in barley plants that lost their characteristic unbranched spike architecture. hvtb2 mutants exhibited branches arising at the main spike, suggesting that, similar to VRS5(HvTB1), HvTB2 act as inhibitor of branching. Taken together, our protein-protein interaction studies of VRS5(HvTB1) resulted in the identification of HvTB2, another key regulator of spike architecture in barley. Understanding the molecular network, including protein-protein interactions, of key regulators of plant architecture such as VRS5(HvTB1) provide new routes towards the identification of other key regulators of plant architecture in barley.Author summaryTranscriptional regulation is one of the basic molecular processes that drives plant growth and development. The key TCP transcriptional regulator TEOSINTE BRANCHED 1 (TB1) is one of these key regulators that has been targeted during domestication of several crops for its role as modulator of branching. Also in barley, a key cereal crop, HvTB1 (also referred to as VRS5), inhibits the outgrowth or side shoots, or tillers, and seeds. Despite its key role in barley development, there is hardly any knowledge on the molecular network that is utilized by VRS5(HvTB1). Transcriptional regulators form homo- and heterodimers to regulate the expression of their downstream targets. Here, we performed an extensive phylogenetic analysis of TCP transcription factors (TFs) in barley, followed by protein-protein interaction studies of VRS5(HvTB1). Our analysis indicates, that VRS5(HvTB1) has a diverse capacity of interacting with class II TCPs, NF-Y TF, but also chromatin modellers. Induced mutagenesis trough CRISPR-CAS mutagenesis of one of the putative VRS5(HvTB1) interactors, HvTB2, resulted in barley plants with branched spikes. This shows that insight into the VRS5(HvTB1) interactome, followed by detailed functional analysis of potential interactors is essential to truly understand how TCPs modulate plant architecture. The study presented here provides a first step to underpin the protein-protein interactome of VRS5(HvTB1) and identify other, yet unknown, key regulators of barley plant architecture.

Pyrenophora teres: Taxonomy, Morphology, Interaction With Barley, and Mode of Control

Net blotch, induced by the ascomycete Pyrenophora teres, has become among the most important disease of barley (Hordeum vulgare L.). Easily recognizable by brown reticulated stripes on the sensitive barley leaves, net blotch reduces the yield by up to 40% and decreases seed quality. The life cycle, the mode of dispersion and the development of the pathogen, allow a quick contamination of the host. Crop residues, seeds, and wild grass species are the inoculum sources to spread the disease. The interaction between the barley plant and the fungus is complex and involves physiological changes with the emergence of symptoms on barley and genetic changes including the modulation of different genes involved in the defense pathways. The genes of net blotch resistance have been identified and their localizations are distributed on seven barley chromosomes. Considering the importance of this disease, several management approaches have been performed to control net blotch. One of them is the use of beneficial bacteria colonizing the rhizosphere, collectively referred to as Plant Growth Promoting Rhizobacteria. Several studies have reported the protective role of these bacteria and their metabolites against potential pathogens. Based on the available data, we expose a comprehensive review of Pyrenophora teres including its morphology, interaction with the host plant and means of control.

Acceptance of Increasing the Productivity of Spring Barley

The aim of this research was to develop a model of productive agrocenoses of spring barley through the application of the growth regulators Biroduks, Vitazim, Emistim and Ribav-Extra. Spraying the plants with the growth regulators led to better growth and the development of leaf blades: the leaf area on one plant increased 1.2-1.74 times. The activation of photosynthetic activity using biological products was established. The most developed assimilation apparatus of the plant was developed under the drug Emistim: the leaf area was 69.224 m2 / ha. The weight of 1000 grains was at its maximum under the influence of Emistim (45.9 g). Less heavy grain was formed by crops under the influence of the Biroduks preparation (45.7 g). In version three, the weight of 1000 grains exceeded the control by 1.9 g. In version five, the increase was 1.4 g. The relationship between the mass of 1000 grains, productive bushiness and yield was a weak straight line (r = 0.19 and r = 0.16, respectively). The increase in yield depended to a greater extent on the number of preserved plants for harvesting (r = 0.98) than on the mass of the grain, the bushiness or the number of grains in the ear. The minimum biological yield was obtained in the control variant and the maximum was with the drug Emistim. Reliability at a 95% significance level was noted on all options. The positive impact on overcoming stressful effects during the growing season of spring barley was most effective when using the drug Emistim. Keywords: spring barley, plant growth regulator, efficiency

Powdery mildew resistance of barley in Southern Dagestan

Background.The most effective way of protecting crops from diseases and pests is the breeding and cultivation of resistant varieties. The hydrothermal regime in the southern plains of Dagest an favors damage to barley plant s by the causative agent of powdery mildew. The high level of disease progress observed annually helps to reliably assess the resistance of collection accessions to the pathogen.Materials and methods.The research material included 1361 barley accessions (570 improved cultivars and 791 landraces) of different ecogeographic origin and growth habit. Field experiments were launched concurrently with winter sowing. Powdery mildew resistance was scored during the heading period and in the milk ripeness phase using a point scale. Each accession was assessed for at least three years.Results and conclusions.The results of a long-term study disclosed a significant intraspecific variability of barley collection accessions in their resistance to powdery mildew. A significant part of the studied barley accessions (63.1%) appeared susceptible to the pathogen. The occurrence frequency of disease-resistant accessions was 11.0%, while those with medium resistance reached 25.9%. Among the landraces, four resistant accessions from the Abyssinian, West Asian and Mediterranean centers of crop origin were identified. Seventeen barley varieties resistant to powdery mildew (predominantly originated from Western Europe) are recommended for use in breeding for immunity.

Influence of foliar fertilization of plants with humid preparations on the productivity of spring barley in the Eastern Forest-Steppe of Ukraine

The article analyzes the current state and improvement of elements of the technology of growing valuable forage and food crops, spring barley in Ukraine. It is noted that in recent years the area under large crops and the yield of this crop have decreased significantly. It is emphasized that further improvement of technologies should be focused on the transition to more use of biological agents to increase yields. Researchers have shown that the effectiveness of the use of humid preparations GK-6M, GK-4MK, GK-MK - on crops of spring barley Dokuchaivsky 15, due to foliar feeding of plants in the tiller ring phase. The main justification of the article is the results of field research conducted in 2015–2019. Maximum indicators, namely: increase in leaf area by 46–38 %, stem height by 8,3 cm; the number of grains in the ear – 4,8 pieces; ear lengths – 1,9 cm; mass of grain in the ear – 0,33 g; masses of 1000 grains – at 12,0 %; nature of grain – 34,9 g – was obtained by treating plants with humid preparation GK-6M. Foliar feeding of plants in the tiller ring phase with the studied drugs provided the largest increase in the yield of spring barley grain – 1,08 t/ha, provided the use of growth stimulant GK-6M. A slightly smaller effect of foliar fertilization of plants on the yield of spring barley was observed from the growth stimulator GK-4MK – the increase in grain yield was 0,83 t/ha and from the growth stimulant GK-MK – the increase in grain yield – 0,66 t/ha. The obtained increments are significant, mathematically proven. Further improvement of agrotechnologies due to wider use of biological means of increase of productivity and quality of production is offered. Keywords: spring barley, plant growth stimulants, foliar feeding, yield.

Genetic Diversity of Barley Foliar Fungal Pathogens

Powdery mildew, net blotch, scald, spot blotch, barley stripe, and leaf rust are important foliar fungal pathogens of barley. Fungal leaf pathogens negatively affect the yield and quality in barley plant. Virulence changes, which can occur in various ways, may render resistant plants to susceptible ones. Factors such as mutation, population size and random genetic drift, gene and genotype flow, reproduction and mating systems, selection imposed by major gene resistance, and quantitative resistance can affect the genetic diversity of the pathogenic fungi. The use of fungicide or disease-resistant barley genotypes is an effective method of disease control. However, the evolutionary potential of pathogens poses a risk to overcome resistance genes in the plant and to neutralize fungicide applications. Factors affecting the genetic diversity of the pathogen fungus may lead to the emergence of more virulent new pathotypes in the population. Understanding the factors affecting pathogen evolution, monitoring pathogen biology, and genetic diversity will help to develop effective control strategies.