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Cel: The aim of the article is to analyse the recording of false alarm cases using the Decision Support System of the State Fire Service (SWD PSP) in terms of certain requirements for a firefighter creating information from an incident. The cases under consideration belong to one of the types of incidents involving fire protection units. Wprowadzenie: Since 1993, when PSP began recording incidents using a database system, the scope of information on false alarms has not changed. To this day, in the incident sheet constituting Annex No. 5 to the regulation on the detailed organization of the national rescue and firefighting system, there is no false alarm as a separate type of incident apart from fire and local emergency. A detailed analysis of the data on false alarms was created in connection with the need to prepare a speech by representatives of KG PSP during a scientific conference organized by CNBOP-PIB entitled “False alarms generated by fire alarm systems”. The authors did not limit themselves to the analysis of alarms from detection installations, and the material was expanded to include a spatial analysis of the occurrence of such events. Metodologia: The results of the authors’ own analyses performed on the basis of data collected in SWD PSP and software from the geographic information systems (GIS) were used. In their deliberations, the authors also relied on years of experience in creating and revising the rules for recording incidents in SWD PSP and building a new information system for fire protection units. Wyniki: Zakres danych gromadzonych przez PSP w zakresie alarmów fałszywych jest niewystarczający do przeprowadzenia dokładnych i wnikliwych analiz, w szczególności w zakresie przyczyn wystąpienia, szczegółowych informacji o obiekcie (miejscu zdarzenia) oraz wyposażeniu budynków w systemy sygnalizacji pożarowej oraz inne ułatwiające lub utrudniające prowadzenie działań jednostkom ochrony przeciwpożarowej. Istnieje pilna potrzeba rozbudowania minimalnego zakresu danych niezbędnych do ewidencjonowania w bazach danych PSP. Przedstawione wyniki analiz wskazują również na niedostateczne rozgraniczenie pomiędzy miejscowym zagrożeniem a alarmem fałszywym. Najbliższa nowelizacja zasad ewidencjonowania zdarzeń ma zawierać zapisy, które powinny poprawić jakość danych. Dokładniejsza analiza będzie jednak możliwa dopiero po wdrożeniu nowobudowanego SWD PSP, uwzględniającego między innymi moduł operacyjnego katalogu obiektów. Wnioski: The scope of data collected by PSP on false alarms is insufficient to carry out accurate and thorough analyses, particularly with regard to the causes of occurrence, detailed information about the facility (site of the incident) and the equipment of buildings with fire alarm systems and others that facilitate or hinder the activities of fire protection units. There is an urgent need to expand the minimum scope of data needed to be recorded in PSP databases. The presented analytical results also indicate that there is insufficient distinction between a local emergency and a false alarm. The upcoming revision of the rules for recording events is expected to include provisions that should improve the quality of data. However, a more detailed analysis will be possible only after the implementation of the newly built SWD PSP, including, among other things, an operational module of the object catalogue. Słowa kluczowe: false alarm, Decision Support System of the State Fire Service, principles of recording incidents, State Fire Service, spatial analysis

Strigolactones (SLs) are a group of plant hormones involved in many aspects of plant development and stress adaptation. Here, we investigated the drought response of a barley (Hordeum vulgare L.) mutant carrying a missense mutation in the gene encoding the SL-specific receptor HvD14. Our results clearly showed that hvd14.d mutant is hyper-sensitive to drought stress. This was illustrated by a lower leaf relative water content (RWC), impaired photosynthesis, disorganization of chloroplast structure, altered stomatal density and slower closure of stomata in response to drought in the mutant compared to the wild type parent cultivar Sebastian. Although the content of abscisic acid (ABA) and its derivatives remained unchanged in the mutant, significant differences in expression of genes related to ABA biosynthesis were observed. Moreover, hvd14.d was insensitive to ABA during seed germination. Analysis of Arabidopsis thaliana mutant atd14-1 also demonstrated that mutation in the SL receptor resulted in increased sensitivity to drought. Our results indicate that the drought-sensitive phenotype of barley SL mutant might be caused by a disturbed ABA metabolism and/or signalling pathways. These results together uncovered a link between SL signalling and ABA-dependent drought stress response in barley.

In the presented study, we have synthesized six nanocomposites based on various magnetic nanoparticles and a conducting polymer, poly(3-hexylthiophene-2,5-diyl) (P3HT). Nanoparticles were either coated with squalene and dodecanoic acid or with P3HT. The cores of the nanoparticles were made of one of three different ferrites: nickel ferrite, cobalt ferrite, or magnetite. All synthesized nanoparticles had average diameters below 10 nm, with magnetic saturation at 300 K varying between 20 to 80 emu/g, depending on the used material. Different magnetic fillers allowed for exploring their impact on the conducting properties of the materials, and most importantly, allowed for studying the influence of the shell on the final electromagnetic properties of the nanocomposite. The conduction mechanism was well defined with the help of the variable range hopping model, and a possible mechanism of electrical conduction was proposed. Finally, the observed negative magnetoresistance of up to 5.5% at 180 K, and up to 1.6% at room temperature, was measured and discussed. Thoroughly described results show the role of the interface in the complex materials, as well as clarify room for improvement of the well-known magnetoelectric materials.

Piwi-interacting RNAs (piRNAs) guide PIWI proteins to bind and cleave RNAs. Originally, piRNAs were described as a system for transposable element repression. Recently, Anzelon, Choudhury, Hughes et al. uncovered the structural basis for piRNA targeting, whereby they are recognized in a manner distinct from targeting by miRNAs.

Precise and efficient use of genome editing tools are hampered by the introduction of DNA double-strand breaks, donor DNA templates, or homology-directed repair. A recent study expands the genome editing toolbox with the introduction of prime editing, which overcomes previous challenges and introduces insertions, deletions, and all putative 12 types of base-to-base conversions in human cells.

The perception mechanism for the strigolactone (SL) class of plant hormones has been a subject of debate because their receptor, DWARF14 (D14), is an α/β-hydrolase that can cleave SLs. Here we show via time-course analyses of SL binding and hydrolysis by Arabidopsis thaliana D14, that the level of uncleaved SL strongly correlates with the induction of the active signaling state. In addition, we show that an AtD14D218A catalytic mutant that lacks enzymatic activity is still able to complement the atd14 mutant phenotype in an SL-dependent manner. We conclude that the intact SL molecules trigger the D14 active signaling state, and we also describe that D14 deactivates bioactive SLs by the hydrolytic degradation after signal transmission. Together, these results reveal that D14 is a dual-functional receptor, responsible for both the perception and deactivation of bioactive SLs., Cleavage of strigolactone by the D14 receptor was assumed to produce an active intermediate that promotes signaling. Here the authors show that D14 activity is not dependent on cleavage activity and propose a new model whereby ligand hydrolysis serves to deactivate strigolactone signaling.

DNA mechanical properties play a critical role in different biological processes. Basu and coworkers described a method that measures DNA mechanics on the genome scale. Access to a high-throughput tool for measuring DNA mechanics opens up new possibilities to investigate this phenomenon with respect to establishing the chromatin regulatory landscape.

Background: Microspore embryogenesis is potentially the most effective method of obtaining doubled haploids (DH) which are utilized in breeding programs to accelerate production of new cultivars. However, the regeneration of albino plants significantly limits the exploitation of androgenesis for DH production in cereals. Despite many efforts, the precise mechanisms leading to development of albino regenerants have not yet been elucidated. The objective of this study was to reveal the genotype-dependent molecular differences in chloroplast differentiation that lead to the formation of green and albino regenerants in microspore culture of barley.Results: We performed a detailed analysis of plastid differentiation at successive stages of androgenesis in two barley cultivars, ‘Jersey’ and ‘Mercada’ that differed in their ability to produce green regenerants. We demonstrated the lack of transition from the NEP-dependent to PEP-dependent transcription in plastids of cv. ‘Mercada’ that produced mostly albino regenerants in microspore culture. The failed NEP-to-PEP transition was associated with the lack of activity of Sig2 gene encoding a sigma factor necessary for transcription of plastid rRNA genes. A very low level of 16S and 23S rRNA transcripts and impaired plastid translation machinery resulted in the inhibition of photomorphogenesis in regenerating embryos and albino regenerants. Furthermore, the plastids present in differentiating ‘Mercada’ embryos contained a low number of plastome copies whose replication was not always completed. Contrary to ‘Mercada’, cv. ‘Jersey’ that produced 90% green regenerants, showed the high activity of PEP polymerase, the highly increased expression of Sig2, plastid rRNAs and tRNAGlu, which indicated the NEP inhibition. The increased expression of GLKs genes encoding transcription factors required for induction of photomorphogenesis was also observed in ‘Jersey’ regenerants. Conclusions: Proplastids present in microspore-derived embryos of albino-producing genotypes did not pass the early checkpoint of their development that are required for induction of further light-dependent differentiation of chloroplasts. The failed activation of plastid-encoded RNA polymerase during differentiation of embryos was associated with the genotype-dependent inability to regenerate green plants in barley microspore culture. The better understanding of molecular mechanism underlying formation of albino regenerants may be helpful in overcoming the problem of albinism in cereal androgenesis.

Cytochrome P450 enzymes encoded by MORE AXILLARY GROWTH1 (MAX1)-like genes produce most of the structural diversity of strigolactones during the final steps of strigolactone biosynthesis. The diverse copies of MAX1 in Oryza sativa provide a resource to investigate why plants produce such a wide range of strigolactones. Here we performed in silico analyses of transcription factors and microRNAs that may regulate each rice MAX1, and compared the results with available data about MAX1 expression profiles and genes co-expressed with MAX1 genes. Data suggest that distinct mechanisms regulate the expression of each MAX1. Moreover, there may be novel functions for MAX1 homologues, such as the regulation of flower development or responses to heavy metals. In addition, individual MAX1s could be involved in specific functions, such as the regulation of seed development or wax synthesis in rice. Our analysis reveals potential new avenues of strigolactone research that may otherwise not be obvious.

Prime editing, developed by Anzalone et al., brings genome editing to a new level, because this approach allows introduction of all mutation types, including insertions, deletions, and all putative 12 types of base-to-base conversions. Previously tested in human cells, this technique has been adapted for use in plants by Lin et al.

Background In recent years the production of biobased biodegradable plastics has been of interest of researchers partly due to the accumulation of non-biodegradable plastics in the environment and to the opportunity for new applications. Commonly investigated are the polyhydroxyalkanoates (PHAs) poly(hydroxybutyrate) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHB-V). The latter has the advantage of being tougher and less brittle. The production of these polymers in bacteria is well established but production in yeast may have some advantages, e.g. the ability to use a broad spectrum of industrial by-products as a carbon sources. Results In this study we increased the synthesis of PHB-V in the non-conventional yeast Arxula adeninivorans by stabilization of polymer accumulation via genetic modification and optimization of culture conditions. An A. adeninivorans strain with overexpressed PHA pathway genes for β-ketothiolase, acetoacetyl-CoA reductase, PHAs synthase and the phasin gene was able to accumulate an unexpectedly high level of polymer. It was found that an optimized strain cultivated in a shaking incubator is able to produce up to 52.1% of the DCW of PHB-V (10.8 g L−1) with 12.3%mol of PHV fraction. Although further optimization of cultivation conditions in a fed-batch bioreactor led to lower polymer content (15.3% of the DCW of PHB-V), the PHV fraction and total polymer level increased to 23.1%mol and 11.6 g L−1 respectively. Additionally, analysis of the product revealed that the polymer has a very low average molecular mass and unexpected melting and glass transition temperatures. Conclusions This study indicates a potential of use for the non-conventional yeast, A. adeninivorans, as an efficient producer of polyhydroxyalkanoates.

Developing plants from in vitro culture of microspores or immature pollen grains (androgenesis) is a highly genotype-dependent process whose effectiveness in cereals is significantly reduced by occurrence of albino regenerants. Here, we examined a hypothesis that the molecular differentiation of plastids in barley microspores prior to in vitro culture affects the genotype ability to regenerate green plants in culture. At the mid-to-late uninucleate (ML) stage, routinely used to initiate microspore culture, the expression of most genes involved in plastid transcription, translation and starch synthesis was significantly higher in microspores of barley cv. ‘Mercada’ producing 90% albino regenerants, than in cv. ‘Jersey’ that developed 90% green regenerants. The ML microspores of cv. ‘Mercada’ contained a large proportion of amyloplasts filled with starch, while in cv. ‘Jersey’ there were only proplastids. Using additional spring barley genotypes that differed in their ability to regenerate green plants we confirmed the correlation between plastid differentiation prior to culture and albino regeneration in culture. The expression of GBSSI gene (Granule-bound starch synthaseI) in early-mid (EM) microspores was a good marker of a genotype potential to produce green regenerants during androgenesis. Initiating culture from EM microspores that significantly improved regeneration of green plants may overcome the problem of albinism.

CRISPR is a prokaryotic defence system that was adapted as a tool for genome editing and has become one of the most important discoveries of this century. CRISPR-associated endonucleases cleave DNA at precise sites, which are marked by complementary short-guided RNA. The recently developed versions of endonucleases are compatible with a broad range of PAM motifs, have a higher specificity and enable a specific nucleotide to be replaced.

The SMC 5/6 complex together with cohesin and condensin is a member of the structural maintenance of chromosome (SMC) protein family. In non-plant organisms SMC5/6 is engaged in DNA repair, meiotic synapsis, genome organization and stability. In plants, the function of SMC5/6 is still enigmatic. Therefore, we analyzed the crucial δ-kleisin component NSE4 of the SMC5/6 complex in the model plant Arabidopsis thaliana. Two functional conserved Nse4 paralogs (Nse4A and Nse4B) are present in A. thaliana, which may have evolved via gene subfunctionalization. Due to its high expression level, Nse4A seems to be the more essential gene, whereas Nse4B appears to be involved mainly in seed development. The morphological characterization of A. thaliana T-DNA mutants suggests that the NSE4 proteins are essential for plant growth and fertility. Detailed investigations in wild-type and the mutants based on live cell imaging of transgenic GFP lines, fluorescence in situ hybridization (FISH), immunolabeling and super-resolution microscopy suggest that NSE4A acts in several processes during plant development, such as mitosis, meiosis and chromatin organization of differentiated nuclei, and that NSE4A operates in a cell cycle-dependent manner. Differential response of NSE4A and NSE4B mutants after induced DNA double strand breaks (DSBs) suggests their involvement in DNA repair processes.

Strigolactones (SLs) and gibberellins (GAs) are plant hormones that share some unique aspects of their perception and signalling pathways. Recent discoveries indicate that these two phytohormones may act together in processes of plant development and that SL biosynthesis is regulated by GAs.

Microscopic investigations of biological objects are an integral part in plant research and most fields of life sciences. They allow the description of morphological, histological, and structural aspects of individual cells or tissues. Based on various cell biological tools and methods it is possible to characterize different plant genotypes or study their adaptation to changing environmental conditions. In combination with antibodies raised against specific antigens and epitopes light and electron microscopy enable investigation of the function of single genes/proteins in plant growth and development or their role related to abiotic or biotic stresses.Here, we describe sample preparation of barley roots for cell biological investigations using light and electron microscopy, to characterize morphological, structural, and functional aspects on root sections and the root surface.

Microscopic investigations of biological objects are an integral part in plant research and most fields of life sciences. They allow the description of morphological, histological, and structural aspects of individual cells or tissues. Based on various cell biological tools and methods it is possible to characterize different plant genotypes or study their adaptation to changing environmental conditions. In combination with antibodies raised against specific antigens and epitopes light and electron microscopy enable investigation of the function of single genes/proteins in plant growth and development or their role related to abiotic or biotic stresses.Here, we describe sample preparation of barley roots for cell biological investigations using light and electron microscopy, to characterize morphological, structural, and functional aspects on root sections and the root surface.

TILLING (Targeting Induced Local Lesions IN Genomes) is a strategy used for functional analysis of genes that combines the classical mutagenesis and a rapid, high-throughput identification of mutations within a gene of interest. TILLING has been initially developed as a discovery platform for functional genomics, but soon it has become a valuable tool in development of desired alleles for crop breeding, alternative to transgenic approach. Here we present the HorTILLUS ( Hordeum-TILLING-University of Silesia) population created for spring barley cultivar "Sebastian" after double-treatment of seeds with two chemical mutagens: sodium azide (NaN3) and N-methyl-N-nitrosourea (MNU). The population comprises more than 9,600 M2 plants from which DNA was isolated, seeds harvested, vacuum-packed, and deposited in seed bank. M3 progeny of 3,481 M2 individuals was grown in the field and phenotyped. The screening for mutations was performed for 32 genes related to different aspects of plant growth and development. For each gene fragment, 3,072-6,912 M2 plants were used for mutation identification using LI-COR sequencer. In total, 382 mutations were found in 182.2 Mb screened. The average mutation density in the HorTILLUS, estimated as 1 mutation per 477 kb, is among the highest mutation densities reported for barley. The majority of mutations were G/C to A/T transitions, however about 8% transversions were also detected. Sixty-one percent of mutations found in coding regions were missense, 37.5% silent and 1.1% nonsense. In each gene, the missense mutations with a potential effect on protein function were identified. The HorTILLUS platform is the largest of the TILLING populations reported for barley and best characterized. The population proved to be a useful tool, both in functional genomic studies and in forward selection of barley mutants with required phenotypic changes. We are constantly renewing the HorTILLUS population, which makes it a permanent source of new mutations. We offer the usage of this valuable resource to the interested barley researchers on cooperative basis.

Strigolactones (SLs) constitute a group of plant hormones which are involved in multiple aspects of plant growth and development. Beside their role in shoot and root development and plant architecture in general, SLs are also involved in plant responses to nutrient deficiency by promoting interactions with symbiotic organisms and via promotion of root elongation. Recent observations on the cross talk between SLs and other hormones demonstrate that the inhibition of adventitious root formation by ethylene is independent of SLs. Additionally, it was shown that root exposure to SLs leads to the accumulation of secondary metabolites, such as flavonols or antioxidants. These data suggest pleiotropic effects of SLs, that influence root development. The discovery that the commonly used synthetic SL analogue racGR24 might also mimic the function of other plant growth regulators, such as karrikins, has led us to consider the previously published publications under the new aspects. This review summarizes present knowledge about the function of SLs in shaping root systems under optimal and nutrient deficiency conditions. Results which appear inconsistent with the various aspects of root development are singled out., Ministerstwo Nauki i Szkolnictwa Wyższego

Marek Marzec is supported by scholarships funded by the Ministry of Science and Higher Education (424/STYP/10/2015 and DN/MOB/245/IV/2015). Ahmad M. Alqudah supported by Leibniz Institute of Plant Genetics and Crop Plant Research (IPK)., The development and growth of plant organs is regulated by phytohormones, which constitute an important area of plant science. The last decade has seen a rapid increase in the unravelling of the pathways by which phytohormones exert their influence. Phytohormones function as signalling molecules that interact through a complex network to control development traits. They integrate metabolic and developmental events and regulate plant responses to biotic and abiotic stress factors. As such, they influence the yield and quality of crops. Recent studies on barley have emphasised the importance of phytohormones in promoting agronomically important traits such as tillering, plant height, leaf blade area and spike/spikelet development. Understanding the mechanisms of how phytohormones interact may help to modify barley architecture and thereby improve its adaptation and yield. To achieve this goal, extensive functional validation analyses are necessary to better understand the complex dynamics of phytohormone interactions and phytohormone networks that underlie the biological processes. The present review summarises the current knowledge on the crosstalk between phytohormones and their roles in barley development. Furthermore, an overview of how phytohormone modulation may help to improve barley plant architecture is also provided., MNiSW

A priority in many crop improvement programs for a long time has been to enhance the tolerance level of plants to both abiotic and biotic stress. Recognition that the root system is the prime determinant of a plant’s ability to extract both water and minerals from the soil implies that its architecture is an important variable underlying a cultivar’s adaptation. The density and/or length of the root hairs (RHs) that are formed are thought to have a major bearing on the plant’s performance under stressful conditions. Any attempt to improve a crop’s root system will require a detailed understanding of the processes of RH differentiation. Recent progress in uncovering the molecular basis of root epidermis specialization has been recorded in the grasses. This review seeks to present the current view of RH differentiation in grass species. It combines what has been learned from molecular-based analyses, histological studies, and observation of the phenotypes of both laboratory- and field-grown plants.

Tannins and hydroxylated aromatic acids, such as gallic acid (3,4,5-trihydroxybenzoic acid), are plant secondary metabolites which protect plants against herbivores and plant-associated microorganisms. Some microbes, such as the yeast Arxula adeninivorans are resistant to these antimicrobial substances and are able to use tannins and gallic acid as carbon sources. In this study, the Arxula gallic acid decarboxylase (Agdc1p) which degrades gallic acid to pyrogallol was characterized and its function in tannin catabolism analyzed. The enzyme has a higher affinity for gallic acid (Km -0.7 ± 0.2 mM, kcat -42.0 ± 8.2 s-1) than to protocatechuic acid (3,4-dihydroxybenzoic acid) (Km -3.2 ± 0.2 mM, kcat -44.0 ± 3.2 s-1). Other hydroxylated aromatic acids, such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid are not gallic acid decarboxylase substrates. A. adeninivorans G1212/YRC102-AYNI1-AGDC1, which expresses the AGDC1 gene under the control of the strong nitrate inducible AYNI1 promoter achieved a maximum gallic acid decarboxylase activity of 1064.4 U/l and 97.5 U/g of dry cell weight in yeast grown in minimal medium with nitrate as nitrogen source and glucose as carbon source. In the same medium, gallic acid decarboxylase activity was not detected for the control strain G1212/YRC102 with AGDC1 expression under the control of the endogenous promoter. Gene expression analysis showed that AGDC1 is induced by gallic acid and protocatechuic acid. In contrast to G1212/YRC102-AYNI1-AGDC1 and G1212/YRC102, A. adeninivorans G1234 [δagdc1] is not able to grow on medium with gallic acid as carbon source but can grow in presence of protocatechuic acid. This confirms that Agdc1p plays an essential role in the tannic acid catabolism and could be useful in the production of catechol and cis, cis-muconic acid. However, the protocatechuic acid catabolism via Agdc1p to catechol seems to be not the only degradation pathway.

They were found to be involved in the communication between plant roots and symbiotic bacteria or fungi, but also in the interactions between roots of host plants and germinating seeds of parasitic plants. Over the years, however, it has become clear that SLs play a regulatory role in many aspects of plant growth and development. Extensive studies on plant model species Arabidopsis thaliana L. and Oryza sativa L. have uncovered the molecular mechanisms of SL biosynthesis and signaling. In some aspects, the SL perception and signaling correspond to the already known mechanisms described for other phytohormones, but in other points, they seem to be unique in the plant kingdom. This chapter summarizes the recent discoveries in the signal transduction pathway of SLs and describes the model of SL perception and signaling.

This work was supported by the European Regional Development Fund through the Innovative Economy for Poland 2007–2013, project WND-POIG.01.03.01-00-101/08 POLAPGEN-BD “Biotechnological tools for breeding cereals with increased resistance to drought,” task 22; National Science Centre, Poland, project SONATA 2015/19/D/NZ9/03573 “Translational genomics approach to identify the mechanisms of CBP20 signalosome in Arabidopsis and barley under drought stress.”, CBP20 (Cap-Binding Protein 20) encodes a small subunit of the cap-binding complex (CBC), which is involved in the conserved cell processes related to RNA metabolism in plants and, simultaneously, engaged in the signaling network of drought response, which is dependent on ABA. Here, we report the enhanced tolerance to drought stress of barley mutant in the HvCBP20 gene manifested at the morphological, physiological, and transcriptomic levels. Physiological analyses revealed differences between the hvcbp20.ab mutant and its WT in response to a water deficiency. The mutant exhibited a higher relative water content (RWC), a lower stomatal conductance and changed epidermal pattern compared to the WT after drought stress. Transcriptome analysis using the Agilent Barley Microarray integrated with observed phenotypic traits allowed to conclude that the hvcbp20.ab mutant exhibited better fitness to stress conditions by its much more efficient and earlier activation of stress-preventing mechanisms. The network hubs involved in the adjustment of hvcbp20.ab mutant to the drought conditions were proposed. These results enabled to make a significant progress in understanding the role of CBP20 in the drought stress response., European Regional Development Fund; National Science Centre, Poland

Reduced plant height and culm robustness are quantitative characteristics important for assuring cereal crop yield and quality under adverse weather conditions. A very limited number of short-culm mutant alleles were introduced into commercial crop cultivars during the Green Revolution. We identified phenotypic traits, including sturdy culm, specific for deficiencies in brassinosteroid biosynthesis and signaling in semidwarf mutants of barley (Hordeum vulgare). This set of characteristic traits was explored to perform a phenotypic screen of near-isogenic short-culm mutant lines from the brachytic, breviaristatum, dense spike, erectoides, semibrachytic, semidwarf, and slender dwarf mutant groups. In silico mapping of brassinosteroid-related genes in the barley genome in combination with sequencing of barley mutant lines assigned more than 20 historic mutants to three brassinosteroid-biosynthesis genes (BRASSINOSTEROID-6-OXIDASE, CONSTITUTIVE PHOTOMORPHOGENIC DWARF, and DIMINUTO) and one brassinosteroid-signaling gene (BRASSINOSTEROID-INSENSITIVE1 [HvBRI1]). Analyses of F2 and M2 populations, allelic crosses, and modeling of nonsynonymous amino acid exchanges in protein crystal structures gave a further understanding of the control of barley plant architecture and sturdiness by brassinosteroid-related genes. Alternatives to the widely used but highly temperature-sensitive uzu1.a allele of HvBRI1 represent potential genetic building blocks for breeding strategies with sturdy and climate-tolerant barley cultivars.

Since the development of the Targeting Induced Local Lesions in Genome (TILLING) strategy, it has been applied in both plants and animals in many studies. The creation of an appropriate population is the first and most crucial step of TILLING. The goal is to obtain a highly mutagenized population that allows many mutations in any gene of interest to be found. Therefore, an effective method of mutation induction should be developed. A high mutation density is associated with saving time, costs, and the labor required for the development of a TILLING platform. The proper handling of the mutated generations, the establishment of a seed bank, and the development of a DNA library are essential for creating a TILLING population. The database in which all of the data from the molecular and phenotypic analyses are collected is a very useful tool for maintaining such population. Once developed, a TILLING population can serve as a renewable resource of mutations for research that uses both forward and reverse genetic approaches. In this chapter, we describe the methods for the development and maintenance of a TILLING population in barley.

The root epidermis of most vascular plants harbours two cell types, namely trichoblasts (capable of producing a root hair) and atrichoblasts. Here, in vivo analysis, confocal laser-scanning microscopy, transmission electron microscopy, histological analysis, and three-dimensional reconstruction were used to characterize the cell types present in the barley root epidermis and their distribution in the tissue. Both trichoblasts and atrichoblasts were present in the wild-type cultivars and could be distinguished from one another at an early stage. Trichoblast/atrichoblast differentiation depended on asymmetric cell expansion after a period of symmetrical cell division. After asymmetric growth, only the shorter epidermal cells could produce root hairs, whereas the longer cells became atrichoblasts. Moreover, the root epidermis did not develop root hairs at all if the epidermal cells did not differentiate into two asymmetric cell types. The root hairless phenotype of bald root barley (brb) and root hairless 1.b (rhl1.b) mutants was caused by a mutation in a gene related to the asymmetric expansion of the root epidermal cells. Additionally, the results showed that the mechanism of trichoblast/atrichoblast differentiation is not evolutionally conserved across the subfamilies of the Poaceae; in the Pooideae subfamily, both asymmetric division and asymmetric cell expansion have been observed.

Strigolactones (SLs) are a new group of plant hormones, which have been intensively investigated during the last few years. The wide spectrum of SLs actions, including the regulation of shoot/root architecture, and the stimulation of the interactions between roots and fungi or bacteria, as well as the stimulation of germination of parasitic plants, indicates that this group of hormones may play an important role in the mechanisms that control soil exploration, and the root-mediated uptake of nutrients. Current studies have shown that SLs might be factors that have an influence on the plant response to a deficiency of macronutrients. Experimental data from the last four years have confirmed that the biosynthesis and exudation of SLs are increased under phosphorus and nitrogen deficiency. All these data suggest that SLs may regulate the complex response to nutrient stress, which include not only the modification of the plant developmental process, but also the cooperation with other organisms in order to minimize the effects of threats. In this paper the results of studies that indicate that SLs play an important role in the response to nutrient stress are reviewed and the consequences of the higher biosynthesis and exudation of SLs in response to phosphorus and nitrogen deficiency are discussed.